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10,900 | Analysis of cardiac fibrillation using phase mapping. | The sequence of myocardial electrical activation during fibrillation is complex and changes with each cycle. Phase analysis represents the electrical activation-recovery process as an angle. Lines of equal phase converge at a phase singularity at the center of rotation of a reentrant wave, and the identification of reentry and tracking of reentrant wavefronts can be automated. We examine the basic ideas behind phase analysis. With the exciting prospect of using phase analysis of atrial electrograms to guide ablation in the human heart, we highlight several recent developments in preprocessing electrograms so that phase can be estimated reliably. |
10,901 | Vasospastic angina resulting in sudden cardiac arrest, initially misdiagnosed as a psychiatric disorder. | A 51-year-old-woman with a history of ablation therapy due to Wolff-Parkinson-White syndrome had been suffering from ambiguous chest pain, prompting investigation by several cardiologists. After being dissatisfied with a psychiatric disorder diagnosis, she was admitted to our hospital for further investigation. She lost her consciousness due to a sudden cardiac arrest shortly after admission. A provocation test indicated vasospastic angina associated with a diffuse spastic pattern of her left anterior descending artery. <<b>Learning objective:</b> This case demonstrates that implantation of a cardioverter defibrillator may be avoided if the angiographic pattern of the vasospasm is recognized, the condition is correctly diagnosed, and appropriate medications are prescribed.>. |
10,902 | [Ventriculer fibrillation due to Prinzmetal angina in a pregnant patient]. | Variant angina, which is also referred to as prinzmetal or coronary vasospastic angina, is a clinical entity characterized by episodes of angina pectoris, usually at rest and often between midnight and early morning, in association with ST-segment elevation on the electrocardiogram. Angina is usually caused by focal spasm of a major coronary artery resulting in a high-grade obstruction, and myocardial infarction may develop in some cases. We report a prinzmetal angina which caused ventricular fibrillation and cardiac arrest in an 18-week pregnant woman. |
10,903 | Characteristics and outcome of congenital left ventricular aneurysm and diverticulum: Analysis of 809 cases published since 1816. | Congenital left ventricular aneurysm (LVA) or diverticulum (LVD) is rare cardiac anomalies. We aimed to analyse the clinical characteristics and outcome in all ever published patients.</AbstractText>MEDLINE, Web of science, Google and EMBASE, and reference lists of relevant articles were searched for publications reporting on LVA or LVD patients.</AbstractText>We identified 809 patients published since 1816 [354 (49.1%) LVA, 453 (50.6%) LVD, 2 (0.3%) both]. Mean age at diagnosis was 34.1±27 (LVA) and 29.7±27.6years (LVD; p=0.05). 48.9% were male. LVA was larger (38.7±22.5mm versus 31.4±21.2mm; p=0.002) and frequently found in submitral location (33% versus 4.9%; p<0.001), LVD was frequently located at the LV-apex (61.2% versus 28.7%; p<0.001). LVD was often associated with cardiac (34.2% versus 11%; p<0.001) or extracardiac anomalies (32.7% versus 3%; p<0.001). LVA patients presented more frequently with ventricular tachycardia/fibrillation (18.1% versus 13.1%; p=0.01), the incidences of rupture (4% versus 4.5%; p=0.9), syncope (8.3% versus 5.1%; p=0.1), and embolic events (4.9% versus 3.6%; p=0.4) at presentation were not different between LVA and LVD. Mean follow-up was 56.3±43months. Cardiac death occurred more frequently in the LVA group (11.5% versus 5.0%; p=0.05) at a median age of 0.8 [LVA] and 2.5 [LVD] years. The leading cause of cardiac death was congestive heart failure in the LVA-group (50.0% versus 0.0%; p=0.01), and rupture in the LVD-group (75.0% versus 27.3%; p=0.04).</AbstractText>LVA and LVD are distinct congenital anomalies with different clinical and morphological characteristics. The prognosis of LVA is significantly worse during long-term follow-up.</AbstractText>Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,904 | Management of atrial fibrillation in bradyarrhythmias. | Sinus node disease (SND), a common indication to implant a pacemaker, is frequently associated with atrial fibrillation (AF), either at implantation (paroxysmal AF) or during follow-up, which often evolves to persistent or permanent AF. Pacemakers with an atrial lead allow continuous monitoring of the atrial rhythm and enable detection of the burden of AF. Asymptomatic atrial tachyarrhythmias, being associated with increased risk of stroke, have important prognostic implications, and their detection could guide decision-making about antithrombotic prophylaxis. Pacing mode and pacing algorithms can influence the occurrence of AF and atrial tachyarrhythmias. In DDD/DDDR pacing mode, reduction of unnecessary right ventricular pacing positively affects the occurrence and evolution of AF, but patients with a history of atrial tachyarrhythmias maintain an increased risk of arrhythmic events. In the MINERVA study, the use of algorithms that act in the atrium for preventive pacing and atrial antitachycardia pacing while minimizing right ventricular pacing was beneficial in patients with SND and previous atrial tachyarrhythmias, and was associated with a significant reduction in evolution to permanent AF. New information available on therapies delivered at the atrial level by implanted devices suggests clinical advantages that could improve current guidelines for the management of AF and atrial tachyarrhythmias. |
10,905 | The incidence of "load&go" out-of-hospital cardiac arrest candidates for emergency department utilization of emergency extracorporeal life support: A one-year review. | The outcome of patients after out-of-hospital cardiac arrest (OHCA) is poor and gets worse after prolonged resuscitation. Recently introduced attempts like an early installed emergency extracorporeal life support (E-ECLS) in patients with persisting cardiac arrest at the emergency department (ED) are tried. The "Vienna Cardiac Arrest Registry" (VICAR) was introduced August 2013 to collect Utstein-style data. The aim of this observational study was to identify the incidence of patients which fulfil "load&go"-criteria for E-ECLS at the ED.</AbstractText>VICAR was retrospectively analyzed for following criteria: age <75 years; witnessed OHCA; basic life support; ventricular fibrillation/ventricular tachycardia; no return-of-spontaneous-circulation (ROSC) within 15 min of advanced-life-support, which were supposed as potential optimal criteria for "load&go" plus successful E-ECLS treatment at the ED. The observation period was from August 1, 2013 to July 31, 2014.</AbstractText>Over 948 OHCA patients registered during the study period; data were exploitable for 864 patients. Of all patients, "load&go"-criteria were fulfilled by 55 (6%). However, 96 (11%) were transported with on-going CPR to the ED. Of these 96 patients, only 16 (17%) met the "load&go"-criteria. Similarly, among the 96 patients, 12 adults were treated with E-ECLS at the ED, with only 5 meeting the criteria. Among these 12 patients, favourable neurological outcome (CPC 1/2) was obtained in 1 patient without criteria.</AbstractText>Further promotion of these criteria within the ambulance crews is needed. May be these criteria could serve as a decision support for emergency physicians/paramedics, which patients to transport with on-going CPR to the ED for E-ECLS.</AbstractText>Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.</CopyrightInformation> |
10,906 | Spinal cord stimulation protects against ventricular arrhythmias by suppressing left stellate ganglion neural activity in an acute myocardial infarction canine model. | Previous studies have shown that spinal cord stimulation (SCS) may reduce ventricular arrhythmias (VAs) induced by acute myocardial infarction (AMI). Furthermore, activation of left stellate ganglion (LSG) appears to facilitate VAs after AMI.</AbstractText>The purpose of this study was to investigate whether pretreatment with SCS could protect against VAs by reducing LSG neural activity in an AMI canine model.</AbstractText>Thirty dogs were anesthetized and randomly divided into SCS group (with SCS, n = 15) and sham group (sham operation without SCS, n = 15). SCS was performed for 1 hour before AMI. Heart rate variability (HRV), ventricular effective refractory period (ERP), serum norepinephrine level, LSG function measured by blood pressure increases in response to LSG stimulation, and LSG neural activity were measured for 1 minute at baseline and 1 hour after SCS. AMI was induced by left anterior descending coronary artery ligation, and then HRV, LSG neural activity, and VAs were measured.</AbstractText>Compared to baseline, SCS for 1 hour significantly prolonged ventricular ERP, increased HRV, and attenuated LSG function and LSG activity in the SCS group, whereas no significant change was shown in the sham group. AMI resulted in a significant decrease in HRV and increase in LSG neural activity in the sham group, which were attenuated in the SCS group (frequency: 99 ± 34 impulses/min vs 62 ± 22 impulses/min; amplitude: 0.41 ± 0.12 mV vs 0.18 ± 0.05 mV; both P <.05). The incidence of VAs was significantly lower in the SCS group than in the sham group.</AbstractText>SCS may prevent AMI-induced VAs, possibly by suppressing LSG activity.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,907 | Impact of the cardiac arrest mode on cardiac death donor lungs. | Donation after cardiac death (DCD) organs could alleviate the shortage of donor lungs. This study aimed to assess the influence on lung injuries of the way in which cardiac arrest was induced and to investigate the mechanisms leading to any differences.</AbstractText>Male rats were allocated into three groups as follows: sham (no warm ischemia), ventricular fibrillation (VF), and asphyxia group. Cardiac arrest was induced by either VF by way of a fibrillator or asphyxia caused by withdrawal of ventilation, which reflected uncontrolled and controlled DCD situations, respectively. The impact on lung flushing after 60 min of warm ischemia time was evaluated (n = 5, in each group). The physiological functions of the lungs in an isolated lung perfusion circuit were also evaluated with warm ischemia time prolonged to 150 min (n = 8, in each group). Messenger RNA expression levels of surfactant proteins (SPs) and inflammatory cytokines, pathologic findings, and high-energy phosphates of the lung tissues were investigated.</AbstractText>In the asphyxia group, flushing and physiological functions in the isolated lung perfusion circuit were the most severely affected. Reverse transcription-polymerase chain reaction and pathologic findings revealed depletion of surfactant protein (SP)-C in lung tissues of the asphyxia group after reperfusion. The VF group was characteristic with elevated pulmonary vascular resistance.</AbstractText>Lung injuries were mainly attributed to alveolar wall damage and depletion of SP in the asphyxia group, and perivascular area prominent edema in the VF group. DCD donor lungs were affected differently by the way in which cardiac arrest was induced.</AbstractText>Copyright © 2015 Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,908 | Acetylcholine Suppresses Ventricular Arrhythmias and Improves Conduction and Connexin-43 Properties During Myocardial Ischemia in Isolated Rabbit Hearts. | Acetylcholine (ACh), a vagal efferent neurotransmitter, markedly improves survival in rats with myocardial ischemia (MI) by preventing ischemic loss of gap junction (Gj) and by inducing anti-apoptotic cascades. However, electrophysiological mechanisms of the antiarrhythmic effect of ACh after acute MI are still unclear.</AbstractText>Acute MI was induced by ligation of the left anterior descending (LAD) coronary artery in Langendorff-perfused rabbit hearts with (ACh(+):n = 11) or without (ACh(-):n = 12) 10 μmol/L ACh delivered continuously starting at 5 minutes before LAD ligation. Action potentials on the left ventricular (LV) anterior surface (≈2×2 cm) were recorded by optical mapping during pacing from the LV epicardium (BCL = 500 milliseconds). Conduction velocities (CVs) at 256 sites were calculated and the ventricular tachycardia/ventricular fibrillation (VT/VF) susceptibility was also assessed by programmed electrical stimulation before and 30 minutes after MI. The amount and distribution of Gj protein connexin-43 was analyzed by immunoblotting and immunohistochemistry.</AbstractText>Averaged CV in the ischemic border zone (IBZ) was significantly slower in ACh(-) than in ACh(+) (21 ± 7 vs. 34 ± 6 cm/s; P < 0.01). Short-coupled extra stimulus further decreased CV of IBZ in ACh(-) (13 ± 4 cm/s) but did not change that in ACh(+) (34 ± 5 cm/s), leading to a high incidence of conduction block in IBZ in ACh(-) but not in ACh(+) (83% vs. 0%). VT/VF after MI were induced in ACh(-) but suppressed in ACh(+) (10/12 vs. 3/11; P < 0.01). Connexin-43 in the LV anterior wall was significantly reduced after MI in ACh(-) but not in ACh(+).</AbstractText>ACh may suppress VT/VF by preventing loss of Gj and improving CV in IBZ during acute MI.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,909 | Apparent asystole: are we missing a lifesaving opportunity? | The use of ultrasonography is rapidly expanding in emergency medicine. Real-time assessment offers clues to prompt diagnosis and creates opportunities for speedy intervention. We present a case of 'cardiac monitor asystole' that proved to be ventricular fibrillation on ultrasound examination. Uniquely this case demonstrates that this, typically unrecognised, form of ventricular fibrillation responds to desynchronised defibrillation, with restoration of perfusion for approximately 30 min. With increasing access to ultrasound we believe that further research is indicated to determine whether some cases of apparent asystole may best be treated by defibrillation, presenting an opportunity to save more lives than current protocols achieve. |
10,910 | Prevalence and predictors of appropriate implantable cardioverter defibrillator therapy in chronic left ventricular dysfunction patients for primary prevention of sudden cardiac death in Siriraj Hospital. | The purpose of the present study was to identify the prevalence and predictors offirst appropriate implantable cardioverter defibrillator (ICD) therapy in patients with chronic LV dysfunction after placement of lCD for primary prevention.</AbstractText>Retrospective design was used. Patients (n = 115) from Siriraj Hospitals with ischemic or non-ischemic cardiomyopathy who underwent ICD implantation for primary prevention were studied. Clinical data and ICD therapy data were obtained from medical records and lCD interrogation reports.</AbstractText>First appropriate ICD therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF) were seen in 22 patients (19%) of whom 11 (9.5%) received lCD shock and 11 patients (9.5%) received anti-tachycardic pacing. Lack of beta-blocker use and lack ofaldosterone antagonist use were identified as significant predictors of appropriate therapy. There was no difference in prevalence of appropriate ICD therapy between ischemic and non-ischemic groups. The freedom from first appropriate therapy at 1, 2 and 3 years was 88%, 80% and 78%. The freedom rate was constant after the third year</AbstractText>Nearly one-fifth of chronic LV dysfunction patients with primary prevention ICD implantation experience appropriate ICD therapy. Most first appropriate ICD therapy occurs within 2 years after implantation. Lack ofbeta-blocker use and lack of aldosterone antagonist use were significant predictors of appropriate therapy.</AbstractText> |
10,911 | Atrial fibrillation complicated by heart failure induces distinct remodeling of calcium cycling proteins. | Atrial fibrillation (AF) and heart failure (HF) are two of the most common cardiovascular diseases. They often coexist and account for significant morbidity and mortality. Alterations in cellular Ca2+ homeostasis play a critical role in AF initiation and maintenance. This study was designed to specifically elucidate AF-associated remodeling of atrial Ca2+ cycling in the presence of mild HF. AF was induced in domestic pigs by atrial burst pacing. The animals underwent electrophysiologic and echocardiographic examinations. Ca2+ handling proteins were analyzed in right atrial tissue obtained from pigs with AF (day 7; n = 5) and compared to sinus rhythm (SR) controls (n = 5). During AF, animals exhibited reduction of left ventricular ejection fraction (from 73% to 58%) and prolonged atrial refractory periods. AF and HF were associated with suppression of protein kinase A (PKA)RII (-62%) and Ca2+-calmodulin-dependent kinase II (CaMKII) δ by 37%, without changes in CaMKIIδ autophosphorylation. We further detected downregulation of L-type calcium channel (LTCC) subunit α2 (-75%), sarcoplasmic reticulum Ca2+-ATPase (Serca) 2a (-29%), phosphorylated phospholamban (Ser16, -92%; Thr17, -70%), and phospho-ryanodine receptor 2 (RyR2) (Ser2808, -62%). Na+-Ca2+ exchanger (NCX) levels were upregulated (+473%), whereas expression of Ser2814-phosphorylated RyR2 and LTCCα1c subunits was not significantly altered. In conclusion, AF produced distinct arrhythmogenic remodeling of Ca2+ handling in the presence of tachycardia-induced mild HF that is different from AF without structural alterations. The changes may provide a starting point for personalized approaches to AF treatment. |
10,912 | Changes in Plasma Atrial and Brain Natriuretic Peptide Levels in Children Undergoing Surgical Isolated Atrial Septal Defect Closure. | Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase after cardiopulmonary bypass (CPB) in pediatric patients. However, the exact reason for the postoperative increase remains unclear. This study elucidated the perioperative changes in plasma natriuretic peptide levels in children undergoing surgical isolated atrial septal defect (ASD) closure. Between 2010 and 2012, 24 pediatric patients (median 7.1, range 2.7-15.7 years) underwent surgery for simple ASD using CPB under ventricular fibrillation (Group A, 16 patients) or under cardiac arrest (Group B, 8 patients). Natriuretic peptide levels were measured before surgery, on postoperative day 0, 1, 3, and at the first outpatient visit. The pulmonary to systemic blood flow ratio (Qp/Qs) was estimated by echocardiography using an index of right ventricle end-diastolic area. Preoperative natriuretic peptide levels positively correlated with the Qp/Qs. Plasma ANP levels peaked on postoperative day 0, and its values were higher in Group A than in Group B patients (p < 0.001). Plasma BNP levels increased significantly in both Groups on postoperative day 1, and its values were significantly greater in Group A than in Group B patients (p = 0.007). There was a weak negative correlation between the amount of postoperative increase in natriuretic peptide levels and the Qp/Qs. There was no appreciable difference in the acute postoperative clinical course and echocardiographic parameter on postoperative day 3 between Group A and B patients. In conclusion, acute postoperative natriuretic peptide levels after isolated ASD closure were multifactorial, and they might be unreliable for predicting clinical outcomes. |
10,913 | LKB1 knockout mouse develops spontaneous atrial fibrillation and provides mechanistic insights into human disease process. | Atrial fibrillation (AF) is a complex disease process, and the molecular mechanisms underlying initiation and progression of the disease are unclear. Consequently, AF has been difficult to model. In this study, we have presented a novel transgenic mouse model of AF that mimics human disease and characterized the mechanisms of atrial electroanatomical remodeling in the genesis of AF.</AbstractText>Cardiac-specific liver kinase B1 (LKB1) knockout (KO) mice were generated, and 47% aged 4 weeks and 95% aged 12 weeks developed spontaneous AF from sinus rhythm by demonstrating paroxysmal and persistent stages of the disease. Electrocardiographic characteristics of sinus rhythm were similar in KO and wild-type mice. Atrioventricular block and atrial flutter were common in KO mice. Heart rate was slower with persistent AF. In parallel with AF, KO mice developed progressive biatrial enlargement with inflammation, heterogeneous fibrosis, and loss of cardiomyocyte population with apoptosis and necrosis. Atrial tissue was infiltrated with inflammatory cells. C-reactive protein, interleukin 6, and tumor necrosis factor α were significantly elevated in serum. KO atria demonstrated elevated reactive oxygen species and decreased AMP-activated protein kinase activity. Cardiomyocyte and myofibrillar ultrastructure were disrupted. Intercellular matrix and gap junction were interrupted. Connexins 40 and 43 were reduced. Persistent AF caused left ventricular dysfunction and heart failure. Survival and exercise capacity were worse in KO mice.</AbstractText>LKB1 KO mice develop spontaneous AF from sinus rhythm and progress into persistent AF by replicating the human AF disease process. Progressive inflammatory atrial cardiomyopathy is the genesis of AF, through mechanistic electrical and structural remodeling.</AbstractText>© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.</CopyrightInformation> |
10,914 | Initial Experience with a New Image Integration Module Designed for Reducing Radiation Exposure During Electrophysiological Ablation Procedures. | Reduction of radiation exposure during cardiac arrhythmia ablation procedures is desirable. We sought to evaluate the utility of a new image integration module (CARTOUNIVU(TM) ) in reducing fluoroscopy times and dosages during left atrial arrhythmia (LAA) and ventricular tachycardia (VT) ablation procedures.</AbstractText>Consecutive patients undergoing LAA (n = 28)/VT (n = 13) ablation using the CARTOUNIVU(TM) module were included. Total fluoroscopy time, radiation dose (total dose area product [tDAP], effective dose [ED]), and procedure duration were evaluated. A retrospective cohort of patients who underwent LAA (n = 16)/VT(n = 8) ablation without the new image integration module served as a control group. The use of the new image integration module significantly reduced mean fluoroscopy time (5.2 minutes [IQR 1.9;6.8] in the LAA ablation UNIVU group vs. 28.2 minutes [IQR 15.3;37.8] in the control group, P<0.001; 9.8 minutes [IQR 4.5;13.1] vs. 25.5 minutes [IQR 14.1;30.9] for VT ablation, P = 0.013), tDAP (2,088 cGy*cm(2) [IQR 664;2911] vs. 5,893 cGy*cm(2) [IQR 3088;8483], P< 0.001 for LAA ablation; 3,917 cGy*cm(2) [IQR 948;4217] vs. 12,377 cGy*cm(2) (IQR 3385;23157) for VT ablation patients, P = 0.025) and ED (4.1 mSv [IQR 1;5.8] vs. 11.8 mSv [IQR 6.2;16.9] for LAA ablation patients, P< 0.001; 7.8 mSv [IQR 1.9;8.4] vs. 24.7 mSv [IQR 6.8;46.3] for VT ablation patients, P = 0.025). Procedure duration did not significantly change (174 ± 45 minutes vs. 197 ± 36 minutes for LAA ablation, P = 0.083; 201 ± 51 minutes vs. 201 ± 63 minutes for VT ablation, P = 0.860). No serious adverse events related to the use of the CARTOUNIVU(TM) module occurred.</AbstractText>The new image integration module significantly reduced total fluoroscopy time and mean radiation dose without influence in procedure duration during ablation of complex atrial and ventricular arrhythmias.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,915 | RyR2 Common Gene Variant G1886S and the Risk of Ventricular Arrhythmias in ICD Patients with Heart Failure. | Cardiac ryanodine receptor 2 (RyR2) is critical to the electrical homeostasis of cardiomyocytes. Its gene variant rs3766871 entails channel destabilization and enhanced intracellular Ca(2+) oscillation, thus promoting cardiac arrhythmias. We investigated whether the RyR2 rs3766871 variant is associated with aborted sudden cardiac death or ICD therapy for ventricular tachycardia (VT)/fibrillation (VF) in heart failure (HF) patients implanted with a cardioverter defibrillator (ICD).</AbstractText>A total of 183 HF patients with primary or secondary prevention ICD were divided in 2 groups. A VT/VF group was composed of secondary prevention patients and primary prevention patients with appropriate ICD intervention for VT/VF. An ICD control group was composed of primary prevention patients free from any appropriate ICD intervention after 43 ± 25 months follow-up. Study subjects were genotyped with respect to the rs3766871 RyR2 gene variant. Hazard ratios (HRs) were derived from Cox proportional-hazards regression analysis. In all, 56 patients constituted the VT/VF group and 127 patients the ICD control group. Male sex (HR: 3.02; 95% CI: 0.99-9.18; P = 0.05), atrial fibrillation (AF; HR: 2.33; 95% CI: 0.89-6.10; P = 0.08), and underuse of β-blockers (HR: 2.08; 95% CI: 0.84-5.15; P = 0.11) were associated with the VT/VF phenotype. Prevalence of the rs3766871 minor allele was 2.8% in ICD control patients and 8.0% in the VT/VF group (P = 0.02). After adjustment for age, sex, AF, and use of β-blockers, the rs3766871 minor allele was associated with increased risk of VT/VF (HR: 3.49; 95% CI: 1.14-10.62; P = 0.02).</AbstractText>Our study identifies a significant role of RyR2 rs3766871 minor allele for increased susceptibility to VT/VF in a population of ICD patients with HF.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,916 | Sequential Percutaneous LAA Ligation and Pulmonary Vein Isolation in Patients with Persistent AF: Initial Results of a Feasibility Study. | Left atrial appendage (LAA) ligation results in LAA electrical isolation and a decrease in atrial fibrillation (AF) burden. This study assessed the feasibility of combined percutaneous LAA ligation and pulmonary vein isolation (PVI) in patients with persistent AF.</AbstractText>A total of 22 patients with persistent AF underwent LAA ligation with the LARIAT device followed by PVI. PVI was confirmed with the demonstration of both entrance and exit block. Patients (n = 10) in sinus rhythm pre- and post-LAA ligation underwent P-wave analysis. Monitoring for AF was performed at 1, 3, and 6 months postablation. LAA ligation was successful in 21 of 22 (95%) patients. The procedure was aborted in one patient due to pericardial adhesions. PVI was performed in 20 of 21 patients. One patient converted to atrial flutter with a controlled ventricular response after LAA ligation and refused subsequent PVI. Demonstration of entrance and exit block was achieved in 19 of 20 patients. At 3 months, 13 of 19 (68.4%) patients were in sinus rhythm. Four patients underwent a second PVI. At 6 months, 15 of 20 (75%) patients were in sinus rhythm. There was a significant decrease in P-wave duration and P-wave dispersion after LAA ligation. Complications with LAA ligation included pericarditis, a delayed pleural effusion, and a late pericardial effusion.</AbstractText>Staged LAA ligation and PVI is feasible and decreases P-wave dispersion. Randomized studies are needed to assess the efficacy of LAA ligation as adjunctive therapy to PVI for maintaining sinus rhythm in patients with persistent AF.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,917 | Rhythm analysis and charging during chest compressions reduces compression pause time. | Prolonged chest compression interruptions immediately preceding and following a defibrillation shock reduce shock success and survival after cardiac arrest. We tested the hypothesis that compression pauses would be shorter using an AED equipped with a new Analysis during Compressions with Fast Reconfirmation (ADC-FR) technology, which features automated rhythm analysis and charging during compressions with brief reconfirmation analysis during compression pause, compared with standard AED mode.</AbstractText>BLS-certified emergency medical technicians (EMTs) worked in pairs and performed two trials of simulated cardiac resuscitation with a chest compression sensing X Series defibrillator (ZOLL Medical). Each pair was randomized to perform a trial of eight 2-min compression intervals (randomly assigned to receive four shockable and four non-shockable rhythms) with the defibrillator in standard AED mode and another trial in ADC-FR mode. Subjects were advised to follow defibrillator prompts, defibrillate if "shock advised," and switch compressors every two intervals. Compression quality data were reviewed using RescueNet Code Review (ZOLL Medical) and analyzed using paired t-tests.</AbstractText>Thirty-two EMT-basic prehospital providers (59% male; median 25 years age [IQR 22-27]) participated in the study. End of interval compression interruptions were significantly reduced with ADC-FR vs. AED mode (p<0.001). For shockable rhythms, pre-shock pause was reduced significantly with ADC-FR compared with AED use (7.35±0.16s vs. 12.0±0.22s, p<0.001) whereas post-shock pause was similar (2.08±0.14s vs. 1.77±0.14s, p=0.1).</AbstractText>Chest compression interruptions associated with rhythm analysis and charging are reduced with use of a novel defibrillator technology, ADC-FR, which features automated rhythm analysis and charging during compressions.</AbstractText>Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,918 | Survival after Public Access Defibrillation in Stockholm, Sweden--A striking success. | In Stockholm, a first responder system and a Public Access Defibrillation (PAD) program has been implemented. Additionally, the number of "unregulated" public Automated External Defibrillators (AEDs) sold "over-the-counter" has increased. The aim of this study was to evaluate the impact on survival from different defibrillation strategies in cases of out-of-hospital cardiac arrest (OHCA) available for PAD.</AbstractText>Retrospective study of all OHCAs in Stockholm, 2006-2012. Witnessed OHCAs occurring outside home with cardiac origin and ventricular fibrillation were considered subjects for PAD. The sites within the PAD program increased from 60 to 135 while the number of unregulated AEDs outside the PAD program increased from 178 to 5016. Of 6532 OHCAs, 7% (n = 474) were defined as subjects for PAD. Of these, 69% (n = 326) were defibrillated by the EMS, 11% (n = 53) by first responders and 16% (n =7 4) by public AEDs. Survival to one month was 31% (n = 101) for cases defibrillated by the EMS, 42% (n = 22) when defibrillated by first responders and 70% (n = 52) when defibrillated by a public AED. The AEDs within the PAD program constituted 2.6% of all public AEDs and were used in 28% (n = 21) of cases when a public AED was used.</AbstractText>In OHCAs available for PAD, 70% of patients survived if a public AED was used. Both the structured AED program as well as the spread of unregulated AEDs was associated with very high survival rates, but the structured approach was more efficient in relation to the number of AEDs used.</AbstractText>Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,919 | Posterior left atrial isolation for atrial fibrillation in left ventricular diastolic impairment is associated with better arrhythmia free survival. | Patients with left ventricular diastolic impairment (LVDI) have higher rates of arrhythmia recurrence following atrial fibrillation (AF) ablation. Past studies have implicated the posterior left atrium (LA) in atrial arrhythmia maintenance in conditions that cause LVDI. We prospectively compared posterior LA isolation (PLAI) with wide antral isolation (WAI) in patients with LVDI having AF ablation.</AbstractText>We conducted a sub-study of a previously published large randomized control study that compared PLAI with WAI. Two hundred and twenty consecutive consenting patients referred for catheter ablation of AF (paroxysmal 135, persistent 48, long standing persistent 37) were recruited (female 43, mean age 59 ± 10 years). Transthoracic echocardiography identified 50 (23%) patients with LVDI and preserved left ventricular systolic function (ejection fraction ≥ 50%). Cox regression analysis was utilized to identify independent predictors of atrial arrhythmia after ablation.</AbstractText>Patients were followed for median 4.6 (inter quartile range 4.0-5.5) years. Patients with LVDI having PLAI had better arrhythmia free survival than patients randomized to conventional ablation (Log rank P=0.028). The only independent predictor of recurrence utilizing Cox regression analysis was ablation strategy (2.3 [1.15-4.74], P=0.026).</AbstractText>Posterior isolation of the LA results in superior atrial arrhythmia free survival in patients with LVDI. Further investigation is required to determine potential mechanisms.</AbstractText>http://www.anzctr.org.au;ACTRN12606000467538.</AbstractText>Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,920 | Prevention of ventricular arrhythmia complicating acute myocardial infarction by local cardiac denervation. | Augmentation of sympathetic nerve activity after acute myocardial infarction (AMI) contributes to fatal arrhythmia. In this study, we investigated whether local ablation of the coronary sinus (CS) and great cardiac vein (GCV) peripheral nerves could reduce ventricular arrhythmias (VA) in a canine AMI model.</AbstractText>Twenty-one anesthetized dogs were randomly assigned into the sham-operated, MI and MI-ablation groups, respectively. The incidence and duration of VA were monitored among different groups. The ventricular effective refractory period (ERP), the ERP dispersion and the ventricular fibrillation threshold (VFT) were measured during the experiments. Norepinephrine (NE) levels in CS blood and cardiac tissue were also detected in this study.</AbstractText>The incidence and duration of VA in MI-ablation group were significantly reduced as compared to the MI dogs (p<0.05). Furthermore, local cardiac denervation drastically prolonged the ventricular ERP in the ischemia area, decreased the ERP dispersion, and reduced NE levels in CS blood (P<0.05). VFT also showed an increased trend in the AMI-ablation group.</AbstractText>The results of this study indicate that, in the canine AMI model, local ablation of CS and GCV peripheral nerves reduces VA occurrence and improves ventricular electrical stability with no obvious effects on heart rate, mean arterial pressure and infarct size. This study suggests that local cardiac denervation may prevent ventricular arrhythmias complicating AMI.</AbstractText>Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,921 | Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies. | Diabetes mellitus (DM) represents one of the most important risk factors for atrial fibrillation (AF) while AF is a strong and independent marker of overall mortality and cardiovascular morbidity in diabetic patients. Autonomic, electrical, electromechanical, and structural remodeling, including oxidative stress, connexin remodeling and glycemic fluctuations seem to be implicated in AF pathophysiology in the setting of DM. The present review highlights the association between DM and AF, provides a comprehensive overview of the responsible pathophysiological mechanisms and briefly discusses potential upstream therapies for DM-related atrial remodeling. |
10,922 | Myocardial fat as a part of cardiac visceral adipose tissue: physiological and pathophysiological view. | Thoracic fat includes extra-pericardial (outside the visceral pericardium) and intra-pericardial (inside the visceral pericardium) adipose tissue. It is called ectopic adipose tissue although it is a normal anatomical structure. Intra-pericardial adipose tissue, which is predominantly composed of epicardial and pericoronary adipose tissue, has a significant role in cardiovascular system function. It provides metabolic-mechanical support to the heart and blood vessels in physiological conditions, while it represents metabolic-cardiovascular risk in case of qualitative and quantitative structural changes in the tissue: it correlates with coronary atherosclerotic disease, left ventricular mass, left atrium enlargement and atrial fibrillation presence. In the last decade there has been mounting evidence of fat cells presence in the myocardium of healthy (non-diseased) persons as well as in persons with both cardiovascular and non-cardiovascular diseases. Thus, it is necessary to clarify the incidence, aetiology, physiological role of fat cells in the myocardium, as well as the clinical significance of pathological fatty infiltration of the myocardium. |
10,923 | Long QT syndrome caused by N-acetyl procainamide in a patient on hemodialysis. | A 65-year-old male on hemodialysis three times a week due to end-stage renal failure underwent cardiac surgery one year previously, and complained of breathlessness on exertion after surgery. Echocardiograms evidenced a significant obstruction in the left ventricular outflow with intraventricular pressure gradient of 62 mmHg, and the patient was started on beta-blocker. After a maximal dose of carvedilol was given, a class 1A antiarrhythmic drug of Na channel blocker, procainamide, was added because of insufficient relief of symptoms. Electrocardiogram (ECG) showed prolonged QT intervals (523 ms) on a regular visit one month after the administration of procainamide, and the dose of procainamide was decreased. On the next day, he was brought to our hospital due to cardiac pulmonary arrest. Initial rhythm was ventricular fibrillation and the corrected QT intervals (QTc) were prolonged (531 ms). Blood examination revealed that N-acetyl procainamide (NAPA), metabolite of procainamide, was significantly higher than the recommended threshold. NAPA was identified as the cause of prolonged QTc and procainamide was stopped. NAPA decreased under the recommended threshold on the seventh day and the QT intervals were normalized. This case report outlines the first case of long QT syndrome caused by NAPA in a hemodialysis patient. <<b>Learning objective:</b> Administration of procainamide could be dangerous even in patients undergoing hemodialysis whose serum procainamide level is within normal limits. We should pay careful attention to it and must not forget to measure the concentrations of procainamide and NAPA. The measurement of QT intervals could help to avoid a fatal side effect.>. |
10,924 | Ranolazine reduces remodeling of the right ventricle and provoked arrhythmias in rats with pulmonary hypertension. | Pulmonary arterial hypertension (PAH) is a progressive disease that often results in right ventricular (RV) failure and death. During disease progression, structural and electrical remodeling of the right ventricle impairs pump function, creates proarrhythmic substrates, and triggers for arrhythmias. Notably, RV failure and lethal arrhythmias are major contributors to cardiac death in patients with PAH that are not directly addressed by currently available therapies. Ranolazine (RAN) is an antianginal, anti-ischemic drug that has cardioprotective effects in experimental and clinical settings of left-sided heart dysfunction. RAN also has antiarrhythmic effects due to inhibition of the late sodium current in cardiomyocytes. We therefore hypothesized that RAN could reduce the maladaptive structural and electrical remodeling of the right ventricle and could prevent triggered ventricular arrhythmias in the monocrotaline rat model of PAH. Indeed, in both in vivo and ex vivo experimental settings, chronic RAN treatment reduced electrical heterogeneity (right ventricular-left ventricular action potential duration dispersion), shortened heart-rate corrected QT intervals in the right ventricle, and normalized RV dysfunction. Chronic RAN treatment also dose-dependently reduced ventricular hypertrophy, reduced circulating levels of B-type natriuretic peptide, and decreased the expression of fibrotic markers. In addition, the acute administration of RAN prevented isoproterenol-induced ventricular tachycardia/ventricular fibrillation and subsequent cardiovascular death in rats with established PAH. These results support the notion that RAN can improve the electrical and functional properties of the right ventricle, highlighting its potential benefits in the setting of RV impairment. |
10,925 | Successful cardiopulmonary cerebral resuscitation in patient with severe acute pancreatitis. | Severe acute pancreatitis (SAP) is a critical illness in clinical practice, which is characterized by intensive inflammatory response in the early phase and infected pancreatic necrosis in the later phase. Despite the knowledge of SAP and critical care support technology got significant progress in recent years, SAP still carries approximately 30%mortality rate. Some SAP patients also have many other kinds of underlying disease such as hyperlipidemia, hypertension, coronary atherosclerotic heart disease, and heart rhythm abnormalities, which are related to cardiopulmonary arrest to some extent. Thus, the incidence of unpredictive cardiopulmonary arrest is high. Recently, a SAP patient in our intensive care unit had sudden cardiac arrest. After 52 minutes of cardiopulmonary resuscitation, she had return of spontaneous circulation and regained consciousness within 2 hours. To our knowledge, there is no successful report after such long resuscitation in SAP patients. She was receiving continuous renal replacement therapy (CRRT) and continuous veno-venous hemofiltration, in the event of cardiopulmonary arrest. No study reported what kind of role CRRT can play when cardiac arrest occurs. Usually, we would stop existing CRRT when cardiac arrest occurred.We would not start CRRT for the complexity of operation and additional loss of blood. This time, we used CRRT to regulate electrolyte and acid-base imbalance and implement hypothermia brain protection, which played an important role in the patient that we report here.We strongly recommended a prolonged cardiopulmonary cerebral resuscitation in some not quite old SAP patients and continue to use existing CRRT but not remove it. |
10,926 | Perspective: a dynamics-based classification of ventricular arrhythmias. | Despite key advances in the clinical management of life-threatening ventricular arrhythmias, culminating with the development of implantable cardioverter-defibrillators and catheter ablation techniques, pharmacologic/biologic therapeutics have lagged behind. The fundamental issue is that biological targets are molecular factors. Diseases, however, represent emergent properties at the scale of the organism that result from dynamic interactions between multiple constantly changing molecular factors. For a pharmacologic/biologic therapy to be effective, it must target the dynamic processes that underlie the disease. Here we propose a classification of ventricular arrhythmias that is based on our current understanding of the dynamics occurring at the subcellular, cellular, tissue and organism scales, which cause arrhythmias by simultaneously generating arrhythmia triggers and exacerbating tissue vulnerability. The goal is to create a framework that systematically links these key dynamic factors together with fixed factors (structural and electrophysiological heterogeneity) synergistically promoting electrical dispersion and increased arrhythmia risk to molecular factors that can serve as biological targets. We classify ventricular arrhythmias into three primary dynamic categories related generally to unstable Ca cycling, reduced repolarization, and excess repolarization, respectively. The clinical syndromes, arrhythmia mechanisms, dynamic factors and what is known about their molecular counterparts are discussed. Based on this framework, we propose a computational-experimental strategy for exploring the links between molecular factors, fixed factors and dynamic factors that underlie life-threatening ventricular arrhythmias. The ultimate objective is to facilitate drug development by creating an in silico platform to evaluate and predict comprehensively how molecular interventions affect not only a single targeted arrhythmia, but all primary arrhythmia dynamics categories as well as normal cardiac excitation-contraction coupling. |
10,927 | Programming implantable cardioverter-defibrillator therapy zones to high ranges to prevent delivery of inappropriate device therapies in patients with primary prevention: results from the RISSY-ICD (Reduction of Inappropriate ShockS bY InCreaseD zones) trial. | Inappropriate shock is a frequently seen clinical problem despite advanced technologies used in modern implantable cardioverter-defibrillator (ICD) devices. Our aim was to investigate whether simply raising the ICD detection zones can decrease inappropriate therapies while still providing appropriate therapy. We randomized 223 patients with primary prevention to either the conventional programming group with 3 zones as VT1 (167 to 182 beats/min) with discriminators, VT2 (182 to 200 beats/min) with discriminators, and ventricular fibrillation (>200 beats/min) (n=100) or the high-zone programming group with 3 zones as VT1 (171 to 200 beats/min) with discriminators, VT2 (200 to 230 beats/min) with discriminators, and ventricular fibrillation (>230 beats/min; n=101). Twenty-two patients were lost to follow-up. The primary objectives were the first episode of appropriate and inappropriate therapies. The secondary objectives were all-cause mortality and hospitalization for heart failure. During 12-month follow-up, the first episode of appropriate therapy was higher (22% vs 10%, hazard ratio [HR] 2.18, 95% confidence interval [CI], 1.09 to 4.36, p=0.028) and the first episode of inappropriate therapy was lower (5% vs 28%, HR 0.18 [95% CI 0.07 to 0.44], p<0.001) in the high-zone group compared with the conventional group. Although all-cause mortality did not differ (2% for the high-zone group vs 3% for the conventional group, HR 0.65 [95% CI 0.11 to 3.99], p>0.05), hospitalization for heart failure was significantly higher in the conventional group (13% vs 4%, HR 0.28 [95% CI 0.09 to 0.88], p=0.021). In conclusion, in a real-world population, high-zone settings of the single-, dual-, and triple-chamber ICDs were associated with reduction in inappropriate therapy while still providing appropriate therapy. |
10,928 | [New studies question the cardiac safety of conducted electrical weapons]. | Conducted electrical weapons (CEW) were invented in the 1970s and are now widely used by more than 16,000 military and law enforcement agencies worldwide. Recent studies have sug-gested that a causal relation of cardiac arrest in humans and utilization of CEW may exist and cardiac capture and fatal arrhythmia have been documented in animal studies. We believe, based on current knowledge, that CEW use may have caused human fatalities. Users should be aware of potential serious side effects and be able to provide basic life support. |
10,929 | Rate control management of atrial fibrillation: may a mathematical model suggest an ideal heart rate? | Despite the routine prescription of rate control therapy for atrial fibrillation (AF), clinical evidence demonstrating a heart rate target is lacking. Aim of the present study was to run a mathematical model simulating AF episodes with a different heart rate (HR) to predict hemodynamic parameters for each situation.</AbstractText>The lumped model, representing the pumping heart together with systemic and pulmonary circuits, was run to simulate AF with HR of 50, 70, 90, 110 and 130 bpm, respectively.</AbstractText>Left ventricular pressure increased by 57%, from 33.92±37.56 mmHg to 53.15±47.56 mmHg, and mean systemic arterial pressure increased by 27%, from 82.66±14.04 mmHg to 105.3±7.6 mmHg, at the 50 and 130 bpm simulations, respectively. Stroke volume (from 77.45±8.50 to 39.09±8.08 mL), ejection fraction (from 61.10±4.40 to 39.32±5.42%) and stroke work (SW, from 0.88±0.04 to 0.58±0.09 J) decreased by 50, 36 and 34%, at the 50 and 130 bpm simulations, respectively. In addition, oxygen consumption indexes (rate pressure product - RPP, tension time index per minute - TTI/min, and pressure volume area per minute - PVA/min) increased from the 50 to the 130 bpm simulation, respectively, by 186% (from 5598±1939 to 15995±3219 mmHg/min), 56% (from 2094±265 to 3257±301 mmHg s/min) and 102% (from 57.99±17.90 to 117.4±26.0 J/min). In fact, left ventricular efficiency (SW/PVA) decreased from 80.91±2.91% at 50 bpm to 66.43±3.72% at the 130 bpm HR simulation.</AbstractText>Awaiting compulsory direct clinical evidences, the present mathematical model suggests that lower HRs during permanent AF relates to improved hemodynamic parameters, cardiac efficiency, and lower oxygen consumption.</AbstractText> |
10,930 | Population movement and sudden cardiac arrest location. | Although the benefits of automatic external defibrillators are undeniable, their effectiveness could be dramatically improved. One of the key issues is the disparity between the locations of automatic external defibrillators and sudden cardiac arrests (SCAs).</AbstractText>From emergency medical services and other Parisian agencies, data on all SCAs occurring in public places in Paris, France, were prospectively collected between 2000 and 2010 and recorded using 2020 grid areas. For each area, population density, population movements, and landmarks were analyzed. Of the 4176 SCAs, 1255 (30%) occurred in public areas, with a highly clustered distribution of SCAs, especially in areas containing major train stations (12% of SCAs in 0.75% of the Paris area). The association with population density was poor, with a nonsignificant increase in SCAs with population density (P=0.4). Occurrence of public SCAs was, in contrast, highly associated with population movements (P<0.001). In multivariate analysis including other landmarks in each grid cell in the model and demographic characteristics, population movement remained significantly associated with the occurrence of SCA (odds ratio, 1.48; 95% confidence interval, 1.34-1.63; P<0.0001), as well as grid cells containing train stations (odds ratio, 3.80; 95% confidence interval, 2.66-5.36; P<0.0001).</AbstractText>Using a systematic analysis of determinants of SCA in public places, we demonstrated the extent to which population movements influence SCA distribution. Our findings also suggested that beyond this key risk factor, some areas are dramatically associated with a higher risk of SCA.</AbstractText>© 2015 American Heart Association, Inc.</CopyrightInformation> |
10,931 | Transcatheter closure of atrial septal defects improves cardiac remodeling and function of adult patients with permanent atrial fibrillation. | Permanent atrial fibrillation (AF) is the most common form of dysrhythmia associated with atrial septal defects (ASDs) in patients older than 40 years. However, little is known about cardiac remodeling after transcatheter closure in patients with permanent AF. This study was designed to compare cardiac events and remodeling effects after transcatheter closure in such patients.</AbstractText>Clinical data of 289 adult patients older than 40 years who underwent ASD closure at our center were analyzed retrospectively. Of them, 63 patients with permanent AF were assigned to the case group, and the other 226 patients without permanent AF were assigned to the control group. Cardiac events and changes in left and right cardiac cavity dimensions before the procedure and 6 months after the procedure were compared between the two groups.</AbstractText>Patients in the case group were significantly older than those in the control group. The right ventricular (RV) volume and right atrial (RA) volume were decreased significantly in both the groups during a median follow-up period of 6 months after closure (P < 0.001). The left atrial dimensions, left ventricular end-systolic dimensions, left ventricular end-diastolic dimensions and left ventricular ejection fraction showed no significant change before and after the procedure in both the groups. Changes of the RV volume and RA volume in the case group were significantly smaller than those in the control group (P = 0.005 and P < 0.001). The New York Heart Association cardiac function was improved in both the groups during the 6 months follow-up period.</AbstractText>The transcatheter closure of ASD can improve the cardiac remodeling and cardiac function in patients with or without AF.</AbstractText> |
10,932 | Update for 2014 on clinical cardiology, geriatric cardiology, and heart failure and transplantation. | In the present article, we review publications from the previous year in the following 3 areas: clinical cardiology, geriatric cardiology, and heart failure and transplantation. Among the new developments in clinical cardiology are several contributions from Spanish groups on tricuspid and aortic regurgitation, developments in atrial fibrillation, syncope, and the clinical characteristics of heart disease, as well as various studies on familial heart disease and chronic ischemic heart disease. In geriatric cardiology, the most relevant studies published in 2014 involve heart failure, degenerative aortic stenosis, and data on atrial fibrillation in the geriatric population. In heart failure and transplantation, the most noteworthy developments concern the importance of multidisciplinary units and patients with preserved systolic function. Other notable publications were those related to iron deficiency, new drugs, and new devices and biomarkers. Finally, we review studies on acute heart failure and transplantation, such as inotropic drugs and ventricular assist devices. |
10,933 | [Effect of anisodamine on myocardial connexin 43 expression in pig after resuscitation from cardiac arrest]. | To investigate the effect of anisodamine on the expression of connexin 43 (Cx43) in swine ventricular myocardium after resuscitation from cardiac arrest.</AbstractText>The experiment was conducted on healthy pigs, and they were randomly divided into three groups, namely sham group, epinephrine group (control group) and anisodamine group (experimental group, animals were resuscitated combined with injection of 0.4 mg/kg of anisodamine), with 5 pigs in each group. Model of ventricular fibrillation was reproduced by alternating current challenge, and cardiopulmonary resuscitation (CPR) was performed 8 minutes after cardiac arrest. Left ventricular myocardium was harvested at 24 hours after restoration of spontaneous circulation. The expression and distribution of Cx43 were observed by immunofluorescence, Cx43 mRNA expression was assessed with reverse transcription-polymerase chain reaction (RT-PCR), and the protein expressions of Cx43 and phosphorylation of Cx43 (p-Cx43) were analyzed by Western Blot.</AbstractText>The positive expression of Cx43 in ventricular muscle was distributed uniformly, mostly at the end-to-end linkage of myocardial cells, with a few side-to-side linkage in sham group. The positive expression of Cx43 in control group was significantly weaker than that in the sham group, and the signal intensity was significantly declined (4.35±2.10 vs. 10.02±3.66, P < 0.01). The positive expression of Cx43 at the end-to-end linkage and side-to-side linkage was irregular in experimental group, and the signal intensity was obviously higher than that in the control group (7.91±2.54 vs. 4.35±2.10, P < 0.05), but it was significantly weaker than that in the sham group (7.91±2.54 vs. 10.02±3.66, P < 0.05). For control group and experimental group, the Cx43 mRNA and protein expressions were significantly lower than those of the sham group [Cx43 mRNA (A value): 0.32±0.05, 0.32±0.03 vs. 0.48±0.07; Cx43 protein (A value): 0.43±0.03, 0.50±0.07 vs. 0.65±0.04, all P < 0.01], and there were no significant differences between experimental group and control group (all P > 0.05). The p-Cx43 protein expression of control group was significantly lower than that of the sham group (A value: 0.22±0.03 vs. 0.37±0.06, P < 0.01), and it was significantly higher in the experiment group than that in the control group (A value: 0.29±0.07 vs. 0.22±0.03, P < 0.01), but there was no significant difference with the sham group (P > 0.05). No significant difference in p-Cx43/Cx43 was found among sham, control, and experiment groups (0.57±0.09, 0.51±0.05, 0.58±0.06, all P > 0.05).</AbstractText>Anisodamine can improve the abnormal expression of Cx43 in ventricular muscle of pigs with cardiac arrest, which may be related to the protection effect of anisodamine on cardiac conduction.</AbstractText> |
10,934 | [The role of pulse oximetry plethysmographic waveform monitoring as a marker of restoration of spontaneous circulation:a pilot study]. | To investigate the feasibility of using pulse oximetry plethysmographic waveform (POP) to identify the restoration of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR).</AbstractText>An observational research was conducted. A porcine model of ventricular fibrillation (VF) arrest was reproduced. After 3 minutes of untreated VF, animals received CPR according to the latest CPR guidelines, providing chest compressions to a depth of 5 cm with a rate of 105 compressions per minute and instantaneous mechanical ventilation. After 2 minutes of CPR, animals were defibrillated with 100 J biphasic, followed by continuous chest compressions. Data of hemodynamic parameters, partial pressure of end-tidal carbon dioxide (PETCO₂) and POP were collected. The change in POP was observed, and the characteristics of changes of the waves were recorded during the peri-CPR period using the time and frequency domain methods.</AbstractText>VF was successfully induced in 6 pigs, except 1 death in anesthesia induction period. (1) After VF, invasive blood pressure waveform and POP of the animals disappeared. PETCO₂was (18.83 ± 2.71) mmHg (1 mmHg=0.133 kPa), and diastolic arterial pressure was (23.83 ± 5.49) mmHg in compression stage. Animals attained ROSC within 1 minute after defibrillation, with PETCO₂[(51.83 ± 9.35) mmHg] and diastolic arterial pressure [(100.67 ± 10.97) mmHg] elevated significantly compared with that of compression stage (t1 = 8.737, t2 = 25.860, both P = 0.000), with appearance of arterial blood pressure waveform.(2) Characteristic changes in POP were found in all experimental animals. During the stages of induced VF, compression, ROSC, and compression termination, POP showed characteristic waveform changes. POP showed disappearance of waveform, regular compression wave, fluctuation hybrid and stable pulse wave in time domain method; while in the frequency domain method waveform disappearance, single peak of compression, double or fusion peak and single peak of pulse were observed.</AbstractText>Analysis of POP using time and frequency domain methods could not only quickly detect cardiac arrest, but also show a role as a feasible, non-invasive marker of ROSC during CPR.</AbstractText> |
10,935 | [Effects of Shenfu injection on the expression of transcription factors T-bet / GATA-3 in pigs with post-resuscitation myocardial dysfunction]. | To examine whether Shenfu injection (SFI) reduces post-resuscitation myocardial dysfunction in a pig model by modulating expression imbalance of transcription factors of regulatory T cell, namely GATA-3 and T-bet.</AbstractText>Thirty pigs were randomly divided into sham group (n = 6) and cardiopulmonary resuscitation (CPR) group (n = 24) according to the random number table method, and the pigs in the CPR group were randomly subdivided into normal saline (NS) group, epinephrine (EP) group, and SFI group (n = 8 per group). After 8 minutes of untreated ventricular fibrillation (VF) followed by 2 minutes of CPR, animals in three groups respectively received central venous injection of either 20 mL SFI (1.0 mL/kg, SFI group), EP (0.02 mg/kg, EP group) or NS (NS group). Blood samples were obtained before VF and 0.5, 2, 6 hours after restoration of spontaneous circulation (ROSC), and the parameters of hemodynamics and oxygen metabolism were determined. Surviving pigs were sacrificed at 24 hours after ROSC, the pathological changes in myocardium were observed, the levels of interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α) and γ-interferon (IFN-γ) were measured by enzyme linked immunosorbent assay (ELISA), and expressions of protein and mRNA of GATA-3 and T-bet were determined by Western Blot and quantitative real-time polymerase chain reaction (RT-qPCR), respectively.</AbstractText>Six pigs of three resuscitation groups were successfully resuscitated. The CPR time, number of defibrillation, defibrillation energy, and ROSC time were significantly decreased in the EP and SFI groups compared with those in the NS group. Compared with the sham group, the parameters of left ventricular systolic function and oxygen metabolism were significantly decreased, myofibril organelles were extensively damaged, and progressive and severe deterioration of the myocardium was found, and mitochondrial structure was not recognizable in the NS group; the level of IL-4 in myocardium were markedly decreased, while that of TNF-α, IFN-γ and IFN-γ/ IL-4 [reflecting helper T cell 1/2 (Th1/Th2)] were significantly increased. Protein and mRNA expressions of GATA-3 were markedly reduced in the myocardium of pigs in the NS group compared with that of the sham group at 24 hours after ROSC, while T-bet was significantly increased. Compared with the NS group, animals treated with SFI had minimal myocardial intracellular damage, with decreased heart rate (HR, bpm: 90.33 ± 3.79 vs. 106.83 ± 5.36) and increased mean arterial pressure (MAP), cardiac output (CO), oxygen delivery (DO₂), and oxygen consumption (VO₂) at 6 hours after ROSC [MAP (mmHg, 1 mmHg = 0.133 kPa): 107.67 ± 1.96 vs. 86.83 ± 1.85, CO (L/min): 2.47 ± 0.08 vs. 2.09 ± 0.04, DO₂ (mL/min): 364.31 ± 4.21 vs. 272.33 ± 3.29, VO₂(mL/min): 95.00±2.22 vs. 82.50 ±2 .28, all P < 0.05]. Compared with the NS groups at 24 hours after ROSC, level of IL-4 was markedly increased in myocardial cells (ng/L: 33.80 ± 3.06 vs. 16.15 ± 1.34, P < 0.05), while the levels of TNF-α, IFN-γ and IFN-γ/IL-4 were lowered significantly [TNF-α (ng/L): 18.16 ± 0.71 vs. 29.64 ± 1.89, IFN-γ (ng/L): 373.75 ± 18.36 vs. 512.86 ± 27.86, IFN-γ/IL-4: 16.15 ± 1.34 vs. 33.80 ± 3.06, all P < 0.05], and myocardial T-bet protein and mRNA expressions were reduced [T-bet protein (gray value): 0.41 ± 0.07 vs. 0.59 ± 0.11, T-bet mRNA (2(-ΔΔCt)): 4.37 ± 0.21 vs. 7.57 ± 0.55, both P < 0.05], furthermore, myocardial GATA-3 protein and mRNA expressions were significantly up-regulated in SFI group [GATA-3 protein (gray value): 0.25 ± 0.07 vs. 0.16 ± 0.07, GATA-3 mRNA (2(-ΔΔCt)): 0.63 ± 0.07 vs. 0.34 ± 0.05, both P < 0.05]. The parameters in SFI group were significantly improved compared with those of the EP group.</AbstractText>Myocardial immune dysfunction is induced by Th1/Th2 imbalance following myocardial injury subsequent to CPR in pigs. SFI can attenuate myocardial injury and regulate myocardial immune disorders, protect post-resuscitation myocardial injury by modulating expression imbalance of transcription factors GATA-3 and T-bet.</AbstractText> |
10,936 | [Effect of pre-arrest and post-arrest mild hypothermia on myocardial function of ventricular fibrillation after restoration of spontaneous circulation in rabbits]. | To study the effect of pre-arrest and post-arrest mild hypothermia after restoration of spontaneous circulation (ROSC) on myocardial function, ultrastructure, apoptosis of myocardial cells in rabbits with ventricular fibrillation.</AbstractText>Sixty-two male New Zealand rabbits were randomly allocated into five groups: namely normothermic control group (NTC group, n = 10), hypothermia control group (HTC group, n = 10), normothermic resuscitation group (NTR group, n = 14), hypothermia pre-arrest group (HPRA group, n = 14), and hypothermia post-arrest group (HPOA group, n = 14). The normal temperature was controlled at (39.0 ± 0.5) centigrade, and the hypothermia (33.5±0.5) centigrade. Ventricular fibrillation cardiac arrest (CA) was reproduced in rabbits by transcutaneous epicardium electrical stimulation. The parameters of hemodynamics were monitored dynamically for 4 hours in all the groups, including heart rate (HR), left ventricular end diastolic and systolic pressure (LVEDP/LVESP), maximal rate of increase/decrease in left ventricular pressure (±dp/dt max), and mean arterial pressure (MAP). The body temperature of rabbits in hypothermia groups was maintained by surface cooling for 4 hours followed by rewarming. The survived rabbits were sacrificed at 48 hours after resuscitation, and myocardial apical tissue was harvested for observation of ultrastructure with electronic microscope, and to observe apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining.</AbstractText>(1) Resuscitation investigation: there was no significant difference in rate of ROSC, time of CPR and energy of defibrillation among HPRA, HPOA, and NTR groups [rate of ROSC: 85.71%, 71.43%, 71.43%; time of CPR (seconds): 45.3 ± 30.2, 61.2 ± 41.3, 82.3 ± 63.8; energy of defibrillation (J): 14.3 ± 8.9, 22.0 ± 15.5, 25.0 ± 15.8, all P > 0.05]. (2) Hemodynamics: compared with normal temperature groups, animals in hypothermia groups exhibited lower levels of HR (all P < 0.05). Compared with NTR group, HPRA group exhibited higher levels of LVESP (mmHg, 1 mmHg = 0.133 kPa) at 0.5, 1, 2 and 3 hours post ROSC (0.5 hour: 103.8 ± 14.3 vs. 91.6 ± 13.3, 1 hour: 107.2 ± 14.1 vs. 82.7 ± 8.5, 2 hours: 109.0 ± 16.9 vs. 88.8 ± 12.9, 3 hours: 109.1 ± 14.6 vs. 89.3 ± 14.3, all P < 0.05). Compared with NTR group and HPOA group, HPRA group exhibited lower levels of LVEDP (mmHg) at 0.5 hour post ROSC (3.70 ± 0.85 vs. 7.61 ± 2.73, 7.02 ± 3.12, both P < 0.05). Compared with NTR group, HPRA group exhibited lower levels of LVEDP at 1 hour post ROSC (4.34 ± 1.44 vs. 6.99±1.96, P < 0.05). In HPRA group, the level of +dp/dt max (mmHg/s) was higher than that of NTR group and HPOA group at 1 hour and 2 hours post ROSC (1 hour: 2 759.5 ± 321.6 vs. 2 123.0 ± 304.5, 2 283.7 ± 234.2, 2 hours: 2 730.6±425.1 vs. 2 221.5 ± 392.9, 2 252.6 ± 476.0, all P < 0.05). There were no significant differences in -dp/dt max and MAP levels among three CPR groups. (3) The survival rate at 48 hours post ROSC of NTR, HPRA and HPOA groups was 60%, 75%, and 100%, respectively. Compared with NTR group, higher survival rate was found in HPOA group at 48 hour post ROSC (P < 0.05). (4) Compared with NTR group, less damage to myocardial ultrastructure was found in HPRA and HPOA groups. Apoptosis index (AI) was lower in HPRA and HPOA groups than that in NTR group [(28.05 ± 9.82) %, (26.39 ± 8.98) % vs. (42.02 ± 13.36) %, both P < 0.05].</AbstractText>Our study shows that mild hypothermia has no effect on ROSC rate. Pre-arrest hypothermia can ameliorate myocardial systolic function of rabbit in early stage after ROSC, and it has no negative influence on diastolic function. Post-arrest mild hypothermia produces no negative influence on myocardial function of rabbit, but it improves 48 hours survival rate in ROSC rabbits. Both pre-arrest and post-arrest mild hypothermia therapy can attenuate myocardial injury in CA model of rabbits by ameliorating mitochondrial injuries and suppressing apoptosis of myocardial cells.</AbstractText> |
10,937 | Homicidal commotio cordis caused by domestic violence: A report of two cases. | Commotio cordis is a rare and fatal mechano-electric arrhythmogenic syndrome, occurring mainly during sports activities. The present study describes two cases of sudden death due to homicidal commotio cordis caused violence from an intimate partner. The two decedents were both young women. They suffered from physical abuse by their intimate partner and collapsed immediately after being punched in the precordium. Electrocardiograms were recorded at the hospital and showed ventricular fibrillation in one case. An autopsy was performed in each case, and no structural cardiac damage, evident lesions of other internal organs or underlying diseases were found. Combined with the negative toxicological analysis, it was concluded that the cause of death was commotio cordis due to a blunt force to the anterior chest. To the best of the authors' knowledge, there is no published report on commotio cordis caused by physical abuse from an intimate partner. The accurate diagnosis of the cause of death is emphasised, as it is important for judicial fairness. |
10,938 | Mild hypothermia inhibits systemic and cerebral complement activation in a swine model of cardiac arrest. | Complement activation has been implicated in ischemia/reperfusion injury. This study aimed to determine whether mild hypothermia (HT) inhibits systemic and cerebral complement activation after resuscitation from cardiac arrest. Sixteen minipigs resuscitated from 8 minutes of untreated ventricular fibrillation were randomized into two groups: HT group (n=8), treated with HT (33°C) for 12 hours; and normothermia group (n=8), treated similarly as HT group except for cooling. Blood samples were collected at baseline and 0.5, 6, 12, and 24 hours after return of spontaneous circulation (ROSC). The brain cortex was harvested 24 hours after ROSC. Complement and pro-inflammatory markers were detected using enzyme-linked immunosorbent assay. Neurologic deficit scores were evaluated 24 hours after ROSC. C1q, Bb, mannose-binding lectin (MBL), C3b, C3a, C5a, interleukin-6, and tumor necrosis factor-α levels were significantly increased under normothermia within 24 hours after ROSC. However, these increases were significantly reduced by HT. Hypothermia decreased brain C1q, MBL, C3b, and C5a contents 24 hours after ROSC. Hypothermic pigs had a better neurologic outcome than normothermic pigs. In conclusion, complement is activated through classic, alternative, and MBL pathways after ROSC. Hypothermia inhibits systemic and cerebral complement activation, which may provide an additional mechanism of cerebral protection. |
10,939 | Alogliptin, a dipeptidyl peptidase-4 inhibitor, regulates the atrial arrhythmogenic substrate in rabbits. | Dipeptidyl peptidase-4 (DPP-4) inhibitors were recently reported to have cardioprotective effects via amelioration of ventricular function. However, the role of DPP-4 inhibition in atrial remodeling, especially of the arrhythmogenic substrate, remains unclear.</AbstractText>We investigated the effects of a DPP-4 inhibitor, alogliptin, on atrial fibrillation (AF) in a rabbit model of heart failure caused by ventricular tachypacing (VTP).</AbstractText>Rabbits subjected to VTP at 380 bpm for 1 or 3 weeks, with or without alogliptin treatment, were assessed using echocardiography, electrophysiology, histology, and immunoblotting and compared with nonpaced animals.</AbstractText>VTP rabbits exhibited increased duration of atrial burst pacing-induced AF, whereas administration of alogliptin shortened this duration by 73%. The extent of atrial fibrosis after VTP was reduced by 39% in the alogliptin-treated group. VTP rabbits treated with alogliptin displayed a 1.6-fold increase in left atrial myocardial capillary density compared with nontreated rabbits. A 2-fold increase in endothelial nitric oxide synthase (eNOS) phosphorylation was observed in the left atrium of alogliptin-treated rabbits compared with nontreated rabbits. Moreover, a nitric oxide synthase inhibitor (N(ω)-nitro-l-arginine methyl ester) blocked the beneficial effects of alogliptin on AF duration, fibrosis, and capillary density.</AbstractText>Alogliptin shortened the duration of AF caused by VTP-induced fibrotic atrial tissue by augmenting atrial angiogenesis and activating eNOS. Our findings suggest that DPP-4 inhibitors may be useful in the prevention of heart failure-induced AF.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,940 | Exercise and the heart--the harm of too little and too much. | Physical activity and exercise training are underutilized by much of Westernized society, and physical inactivity may be the greatest threat to health in the 21st century. Many studies have shown a linear relationship between one's activity level and heart health, leading to the conclusion that "if some exercise is good, more must be better." However, there is evolving evidence that high levels of exercise may produce similar or less overall cardiovascular (CV) benefits compared with those produced by lower doses of exercise. Very high doses of exercise may be associated with increased risk of atrial fibrillation, coronary artery disease, and malignant ventricular arrhythmias. These acute bouts of excessive exercise may lead to cardiac dilatation, cardiac dysfunction, and release of troponin and brain natriuretic peptide. The effects of too little and too much exercise on the heart are reviewed in this article, along with recommendations to optimize the dose of exercise to achieve heart health. |
10,941 | Enhanced perfusion during advanced life support improves survival with favorable neurologic function in a porcine model of refractory cardiac arrest. | To improve the likelihood for survival with favorable neurologic function after cardiac arrest, we assessed a new advanced life support approach using active compression-decompression cardiopulmonary resuscitation plus an intrathoracic pressure regulator.</AbstractText>Prospective animal investigation.</AbstractText>Animal laboratory.</AbstractText>Female farm pigs (n = 25) (39 ± 3 kg).</AbstractText>Protocol A: After 12 minutes of untreated ventricular fibrillation, 18 pigs were randomized to group A-3 minutes of basic life support with standard cardiopulmonary resuscitation, defibrillation, and if needed 2 minutes of advanced life support with standard cardiopulmonary resuscitation; group B-3 minutes of basic life support with standard cardiopulmonary resuscitation, defibrillation, and if needed 2 minutes of advanced life support with active compression-decompression plus intrathoracic pressure regulator; and group C-3 minutes of basic life support with active compression-decompression cardiopulmonary resuscitation plus an impedance threshold device, defibrillation, and if needed 2 minutes of advanced life support with active compression-decompression plus intrathoracic pressure regulator. Advanced life support always included IV epinephrine (0.05 μg/kg). The primary endpoint was the 24-hour Cerebral Performance Category score. Protocol B: Myocardial and cerebral blood flow were measured in seven pigs before ventricular fibrillation and then following 6 minutes of untreated ventricular fibrillation during sequential 5 minutes treatments with active compression-decompression plus impedance threshold device, active compression-decompression plus intrathoracic pressure regulator, and active compression-decompression plus intrathoracic pressure regulator plus epinephrine.</AbstractText>Protocol A: One of six pigs survived for 24 hours in group A versus six of six in groups B and C (p = 0.002) and Cerebral Performance Category scores were 4.7 ± 0.8, 1.7 ± 0.8, and 1.0 ± 0, respectively (p = 0.001). Protocol B: Brain blood flow was significantly higher with active compression-decompression plus intrathoracic pressure regulator compared with active compression-decompression plus impedance threshold device (0.39 ± 0.23 vs 0.27 ± 0.14 mL/min/g; p = 0.03), whereas differences in myocardial perfusion were not statistically significant (0.65 ± 0.81 vs 0.42 ± 0.36 mL/min/g; p = 0.23). Brain and myocardial blood flow with active compression-decompression plus intrathoracic pressure regulator plus epinephrine were significantly increased versus active compression-decompression plus impedance threshold device (0.40 ± 0.22 and 0.84 ± 0.60 mL/min/g; p = 0.02 for both).</AbstractText>Advanced life support with active compression-decompression plus intrathoracic pressure regulator significantly improved cerebral perfusion and 24-hour survival with favorable neurologic function. These findings support further evaluation of this new advanced life support methodology in humans.</AbstractText> |
10,942 | Reduced pre-hospital and in-hospital survival rates after out-of-hospital cardiac arrest of patients with type-2 diabetes mellitus: an observational prospective community-based study. | Out-of-hospital cardiac arrest (OHCA) remains a major cause of death. We aimed to determine whether type-2 diabetes mellitus (T2DM) is associated with reduced pre-hospital and in-hospital survival rates after OHCA.</AbstractText>An observational community-based cohort study was performed among 1549 OHCA patients with ECG-documented ventricular tachycardia/ventricular fibrillation (VT/VF). We compared pre-hospital and in-hospital survival rates between T2DM patients and non-diabetic patients. Analyses among T2DM patients were stratified according to current T2DM treatment, used as proxy for T2DM severity. Proportions of neurologically intact survival were analysed. Pre-hospital survival rates were lower in T2DM patients (n = 275) than in non-diabetic patients (n = 1274); 48.7 vs. 55.8% (univariate P = 0.032). Type-2 diabetes mellitus was associated with lower pre-hospital survival [OR 0.75 (0.58-0.98); after evaluation of the risk factors, we found no relevant confounding]. Patients treated with insulin only had lower pre-hospital survival rates than patients treated with oral glucose-lowering drugs only (37.3 vs. 53.3%, univariate P = 0.034), partially explained by location of OHCA and EMS response time [ORadj 0.62 (0.33-1.17)]. In-hospital survival rates were also lower in T2DM patients (n = 134) than in non-diabetic patients (n = 711); 40.3 vs. 57.7%, univariate P < 0.001. In those patients whose cause of OHCA was retrieved (n = 771), T2DM was significantly associated with lower in-hospital survival [ORadj 0.57 (0.37-0.87)]. Neurologically intact status at discharge was similarly high among T2DM and non-diabetic patients (94.4 vs. 94.6%, P = 0.954).</AbstractText>T2DM is associated with lower pre-hospital and in-hospital survival rates after OHCA. Neurologically intact status at hospital discharge is high both among T2DM and non-diabetic patients.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
10,943 | Stand alone totally endoscopic epimyocardial ablation in patients with persistent atrial fibrillation and significant atrial dilatation. | To analyze safety and efficacy of surgical totally endoscopic epimyocardial ablation in patients (pts) turned down for interventional catheter therapy due to long-standing persistent atrial fibrillation (pAF) combined with significant atrial dilatation (> 5 cm).</AbstractText>Since December 2010, 15 pts were referred for surgical ablation due to persistent AF combined with biatrial dilatation (left atrium [LA] 5.0 ± 0.6 cm). Mean age was 52 ± 6 years, body mass index (BMI) 38 ± 6, duration of AF 2.8 ± 1.2 years, left ventricular end diastolic diameter (LVEDD) 5.8 cm ± 0.6 cm. Ablation was performed via a bilateral endoscopic approach using bipolar RF energy application. Monitoring was achieved by an event recorder (Reveal XT Medtronic, Inc., Minneapolis, MN, USA) or repeated 24-hours Holter electrocardiogram.</AbstractText>All pts successfully received bilateral pulmonary vein isolation + box lesion + trigonal lesion + left atrial appendage resection. Mean duration of procedure was 235 ± 70 minutes. There was no intraoperative complication; however, one patient had persistent left phrenic nerve palsy. Mean hospital stay was 4 ± 2 days, mean follow-up time was 21 ± 11 months. Incidence of sinus rhythm (SR) was 67, 73, and 80% at discharge, three months, and 12 months follow-up. Mean LA diameter was reduced from 58.1 mm ± 6.0 mm preoperative to 49.7 mm ± 5.4 mm (p = 0.004) at 12 months follow-up. Incidence of SR was 86% at latest follow-up (mean time 21 months). All pts currently in SR (13/15 = 86%) are of class I or III antiarrhythmic drugs.</AbstractText>Totally endoscopic left atrial ablation including left atrial resection can safely be performed. It achieved excellent rates of SR restoration in patients with long-standing persistent AF combined with significant atrial dilatation.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,944 | Effectiveness of mechanical chest compression for out-of-hospital cardiac arrest patients in an emergency department. | To increase the chance of restoring spontaneous circulation, cardiopulmonary resuscitation (CPR) with high-quality chest compressions is needed. We hypothesized that, in a municipal hospital emergency department, the outcome in nontraumatic out-of-hospital cardiac arrest patients treated with standard CPR followed by mechanical chest compression (MeCC) was not inferior to that followed by manual chest compression (MaCC). The purposes of the study were to test our hypothesis and investigate whether the use of MeCC decreased human power demands for CPR.</AbstractText>A total of 455 consecutive out-of-hospital cardiac arrest patients of presumed cardiac etiology were divided into two groups according to the chest compressions they received (MaCC or MeCC) in this retrospective review study. Human power demand for CPR was described according to the Basic Life Support/Advanced Cardiovascular Life Support guidelines and the device handbook. The primary endpoint was recovery of spontaneous circulation during resuscitation, and the secondary endpoints were survival to hospital admission and medical human power demands.</AbstractText>In this study, recovery of spontaneous circulation was achieved in 33.3% of patients in the MeCC group and in 27.1% in the MaCC group (p = 0.154), and the percentages of patients who survived hospitalization were 22.2% and 17.6%, respectively (p = 0.229). A ratio of 2:4 for the human power demand for CPR between the groups was found. Independent predictors of survival to hospitalization were ventricular fibrillation/pulseless ventricular tachycardia as initial rhythm and recovery of spontaneous circulation.</AbstractText>No difference was found in early survival between standard CPR performed with MeCC and that performed with MaCC. However, the use of the MeCC device appears to promote staff availability without waiving patient care in the human power-demanding emergency departments of Taiwan hospitals.</AbstractText>Copyright © 2015. Published by Elsevier Taiwan.</CopyrightInformation> |
10,945 | Relationship between duration of prehospital resuscitation and favorable prognosis in ventricular fibrillation. | There appears to be an optimal point in balancing the relative benefits of extending the resuscitation time to obtain return of spontaneous circulation in the prehospital setting and the initiation of therapies such as extracorporeal cardiopulmonary resuscitation (CPR). This study investigated how prehospital CPR duration is related to survival and neurologic outcome in ventricular fibrillation (VF) and tried to find the tolerable time for prehospital resuscitation.</AbstractText>Out-of-hospital cardiac arrest patients with VF in Funabashi City, Japan, from January 2009 to December 2013 were reviewed. Resuscitation teams that included physicians were dispatched to incident sites. Survival rate at 24 hours and neurologic outcome at 30 days were analyzed with respect to prehospital CPR duration.</AbstractText>A total of 172 patients were evaluated. Seventy-three patients were alive at 24 hours. Thirty-four patients had favorable neurologic outcomes after 30 days. Of the 69 patients who required prolonged prehospital CPR (>30 minutes), 6 were alive at 24 hours, and only 1 had a favorable neurologic outcome at 30 days. Logistic regression model showed that both survival rate at 24 hours and neurologic outcome at 30 days deteriorated with the increase in prehospital CPR duration (both P < .001).</AbstractText>The prognosis of out-of-hospital cardiac arrest patients with VF deteriorated with the increase in prehospital CPR duration. Favorable results are less likely especially in cases of prolonged prehospital CPR (>30 minutes). Therefore, it may be necessary to consider transportation to a more definitive treatment facility rather than extending conventional CPR in the prehospital setting.</AbstractText>Copyright © 2015 Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,946 | Prognosis importance of low flow in aortic stenosis with preserved LVEF. | Previous studies using echocardiography suggested that a low flow (LF) defined as an indexed stroke volume (SVi) <35 mL/m(2) may be an important determinant of outcome in patients with severe aortic stenosis (AS). We sought to assess the prognostic importance of stroke volume derived from invasive data. The aim of this study was to determine the impact of LF, purposely derived from cardiac catheterisation data, on outcome of patients with severe AS and preserved LVEF.</AbstractText>Between 2000 and 2010, 768 patients with preserved LVEF (>50%) and severe AS (valve area ≤1 cm(2)) without other valvular heart disease underwent cardiac catheterisation. The long-term overall mortality was assessed as the primary end-point.</AbstractText>Mean age was 74±8 years, 58% were men, 46% had coronary artery disease and mean LVEF was 72±10%. Low SVi was found in 27% (n=210) of patients with AS. As compared with patients with normal SVi, those with low SVi were significantly older (p<0.0001) with higher rate of atrial fibrillation (p<0.0001). Additionally, they had lower LVEF (p=0.046), aortic valve area (p<0.0001), mean pressure gradient (p<0.0001), systemic arterial compliance (p<0.0001) and higher systemic vascular resistances (p<0.0001). Eight-year survival was significantly reduced in patients with low SVi as compared with those with normal SVi (51±5% vs 67±3%; p<0.0001). After adjustment for all other risk factors, reduced SVi was independently associated with long-term mortality (HR=1.45, 95% CI 1.1 to 2.1; p=0.048).</AbstractText>In patients with severe AS and preserved LVEF, LF, as assessed using cardiac catheterisation is frequent, and is an independent predictor of mortality. Consequently, the measurement of SVi should be systematically included in the assessment of these patients.</AbstractText>Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.</CopyrightInformation> |
10,947 | VV' Alternans Triplets on Near-Field ICD Intracardiac Electrogram is Associated with Mortality. | In heart failure patients with implantable cardioverter defibrillator (ICD) the risk of death from causes other than tachyarrhythmia is substantial. Benefit from ICD is determined by two competing risks: appropriate ICD shock or nonarrhythmic death. The goal of the study was to test predictors of competing outcomes.</AbstractText>Patients with structural heart disease (N = 234, mean age 58.5 ± 15.1; 71% men, 80% whites, 61% ischemic cardiomyopathy) and primary (75%) or secondary prevention ICD underwent a 5-minute baseline near-field electrogram (NF EGM) recording. VV' alternans triplets were quantified as a percentage of three sinus VV' cycles sequences of "short-long-short" or "long-short-long" order. Appropriate ICD shock for fast ventricular tachycardia (FVT, cycle length ≤240 ms)/ventricular fibrillation (VF) and composite nonarrhythmic death (pump failure death or heart transplant) served as competing outcomes.</AbstractText>Over a median follow-up of 2.4 years, 26 patients (4.6% per person-year of follow-up) developed FVT/VF with ICD shock, and 35 (6.3% per person-year of follow-up) had nonarrhythmic death. In competing risk analysis, after adjustment for demographics, left ventricular ejection fraction, New York Heart Association class, cardiomyopathy type, use of class I antiarrhythmics, and diabetes, increased percentage of VV' alternans triplets (>69%) was associated with nonarrhythmic death (subhazard ratio [SHR] 2.09; 95% confidence interval [CI] 1.03-4.23; P = 0.041), rather than with FVT/VF (SHR 1.05; 95% CI 0.45-2.46; P = 0.901). Risk of nonarrhythmic death was especially high in diabetics with VV' alternans triplets in the highest quartile (SHR 3.46; 95% CI 1.41-8.50; P = 0.007).</AbstractText>In ICD patients with structural heart disease sinus VV' alternans triplets on NF EGM is independently associated with nonarrhythmic death, rather than with FVT/VF.</AbstractText>©2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,948 | Some Controversies about Early Repolarization: The Haïssaguerre Syndrome. | Controversy has followed the groundbreaking and cornerstone paper of Haïssaguerre et al. Much of this controversy has been due to the use of the term "early repolarization pattern" and possible waveform morphologies on the standard 12-lead ECG ( it is 10 second strip) that could predict who will manifest the malignant arrhythmogenic syndrome described by Haïssaguerre et al. The standard ECG definition of early repolarization pattern (ERP) or early repolarization variant (ERV) since then has changed its clinical meaning for a surface electrocardiographic waveform from benign to malignant. The new definition of ERP/ERV contains only J wave but ST-segment elevation is no more obligatory. In the old definition, early repolarization pattern (ERP) or early repolarization variant (ERV) 3 is a well-recognized idiopathic electrocardiographic phenomenon considered to be present when at least two adjacent precordial leads show elevation of the ST segment, with values equal or higher than 1 mm. In the new electrocardiographic ERP concept, the ST segment may or may not be elevated and can be up-sloping, horizontal or down-sloping while in the old ERP/ERV concept it must be elevated at least 1 mm in at least two adjacent leads and the variant is characterized by a diffuse elevation of the ST segment of upper concavity, ending in a positive T wave of V2 to V4 or V5 and prominent J wave and ST-segment elevation predominantly in left precordial leads. The phenomenon constitutes a normal variant; it is almost a rule in athletes (present in 89% of the cases in this universe). |
10,949 | Comparison of Shenfu Injection () and epinephrine on catecholamine levels in a porcine model of prolonged cardiac arrest. | To compare the effects of Shenfu Injection (SFI) and epinephrine (EPI) on catecholamine levels in a porcine model of prolonged cardiac arrest (CA).</AbstractText>After 8 min of untreated ventricular fibrillation, 24 Wuzhishan miniature pigs were randomly assigned to one of the three groups (n=8 per group) and received central venous injection, respectively: SFI group (1 mL/kg), EPI group (20 μg/kg EPI), and normal saline (NS) group. Cardiac output (CO), maximum rate of increase/decrease in left ventricular pressure (±dp/dt), serum levels of EPI, norepinephrine (NE), and dopamine (DA) were determined at baseline and at 0.5, 1, 2, and 4 h after restoration of spontaneous circulation.</AbstractText>The duration of cardiopulmonary resuscitation was shorter in the EPI and SFI groups than in the NS group (P<0.05). The EPI level increased significantly after restoration of spontaneous circulation (ROSC) in all three groups, and was significantly different between the EPI group and the other two groups immediately after ROSC (both P<0.01), but these differences gradually disappeared over time. There were no significant differences in NE or DA levels among the three groups, and there were no correlations between catecholamine levels and CO or dp/dt (P>0.05).</AbstractText>SFI did not significantly affect endogenous catecholamine levels during cardiopulmonary resuscitation after prolonged ventricular fibrillation. However, SFI improved oxygen metabolism, and produced a better hemodynamic status compared with EPI. SFI might be a potentially vasopressor drug for the treatment of CA.</AbstractText> |
10,950 | Digoxin use in patients with atrial fibrillation and adverse cardiovascular outcomes: a retrospective analysis of the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF). | Digoxin is a widely used drug for ventricular rate control in patients with atrial fibrillation (AF), despite a scarcity of randomised trial data. We studied the use and outcomes of digoxin in patients in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF).</AbstractText>For this retrospective analysis, we included and classified patients from ROCKET AF on the basis of digoxin use at baseline and during the study. Patients in ROCKET AF were recruited from 45 countries and had AF and risk factors putting them at moderate-to-high risk of stroke, with or without heart failure. We used Cox proportional hazards regression models adjusted for baseline characteristics and drugs to investigate the association of digoxin with all-cause mortality, vascular death, and sudden death. ROCKET AF was registered with ClinicalTrials.gov, number NCT00403767.</AbstractText>In 14,171 randomly assigned patients, digoxin was used at baseline in 5239 (37%). Patients given digoxin were more likely to be female (42% vs 38%) and have a history of heart failure (73% vs 56%), diabetes (43% vs 38%), and persistent AF (88% vs 77%; p<0·0001 for each comparison). After adjustment, digoxin was associated with increased all-cause mortality (5·41 vs 4·30 events per 100 patients-years; hazard ratio 1·17; 95% CI 1·04-1·32; p=0·0093), vascular death (3·55 vs 2·69 per 100 patient-years; 1·19; 1·03-1·39, p=0·0201), and sudden death (1·68 vs 1·12 events per 100 patient-years; 1·36; 1·08-1·70, p=0·0076).</AbstractText>Digoxin treatment was associated with a significant increase in all-cause mortality, vascular death, and sudden death in patients with AF. This association was independent of other measured prognostic factors, and although residual confounding could account for these results, these data show the possibility of digoxin having these effects. A randomised trial of digoxin in treatment of AF patients with and without heart failure is needed.</AbstractText>Janssen Research & Development and Bayer HealthCare AG.</AbstractText>Copyright © 2015 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
10,951 | Renal function and peak exercise oxygen consumption in chronic heart failure with reduced left ventricular ejection fraction. | Chronic kidney disease is associated with sympathetic activation and muscle abnormalities, which may contribute to decreased exercise capacity. We investigated the correlation of renal function with peak exercise oxygen consumption (V̇O2) in heart failure (HF) patients. METHODS AND RESULTS: We recruited 2,938 systolic HF patients who underwent clinical, laboratory, echocardiographic and cardiopulmonary exercise testing. The patients were stratified according to estimated glomerular filtration rate (eGFR). Mean follow-up was 3.7 years. The primary outcome was a composite of cardiovascular death and urgent heart transplantation at 3 years. On multivariable regression, eGFR was predictor of peakV̇O2(P<0.0001). Other predictors were age, sex, body mass index, HF etiology, NYHA class, atrial fibrillation, resting heart rate, B-type natriuretic peptide, hemoglobin, and treatment. After adjusting for significant covariates, the hazard ratio for primary outcome associated with peakV̇O2<12 ml·kg(-1)·min(-1)was 1.75 (95% confidence interval (CI): 1.06-2.91; P=0.0292) in patients with eGFR ≥60, 1.77 (0.87-3.61; P=0.1141) in those with eGFR of 45-59, and 2.72 (1.01-7.37; P=0.0489) in those with eGFR <45 ml·min(-1)·1.73 m(-2). The area under the receiver-operating characteristic curve for peakV̇O2<12 ml·kg(-1)·min(-1)was 0.63 (95% CI: 0.54-0.71), 0.67 (0.56-0.78), and 0.57 (0.47-0.69), respectively. Testing for interaction was not significant.</AbstractText>Renal dysfunction is correlated with peakV̇O2. A peakV̇O2cutoff of 12 ml·kg(-1)·min(-1)offers limited prognostic information in HF patients with more severely impaired renal function.</AbstractText> |
10,952 | Papaverine-induced polymorphic ventricular tachycardia during coronary flow reserve study of patients with moderate coronary artery disease. | Papaverine is useful for evaluating the functional status of a coronary artery, but it may provoke malignant ventricular arrhythmia (VA). The aim of this study was to investigate the incidence, and clinical and ECG characteristics of patients with papaverine-induced VAs. METHODS AND RESULTS: The 182 consecutive patients underwent fractional flow reserve (FFR) measurement of 277 lesions. FFR was determined after intracoronary papaverine administration by standard procedures. The clinical and ECG characteristics were compared between patients with and without ventricular tachycardia (VT: ≥3 successive premature ventricular beats (PVBs), or ventricular fibrillation (VF)). After papaverine administration, the QTc interval, QTUc interval, and T-peak to U-end interval were prolonged significantly. Single PVBs on the T-wave or U-wave type developed in 29 patients (15.9%). Polymorphic VT (torsade de pointes) occurred in 5 patients (2.8%), and of those, VF developed in 3 patients (1.7%). No clinical and baseline ECG parameters were predictors for VT or VF except for sex and administration of papaverine into the left coronary artery. Excessive prolongation of QT (or QTU), T-peak to U-end intervals and giant T-U waves were found immediately prior to the ventricular tachyarrhythmias (VTAs), which were unpredictable from the baseline data.</AbstractText>Intracoronary administration of papaverine induced fatal VTAs, although the incidence is rare. Excessive prolongation of the QT (and QTU) interval appeared prior to VTAs; however, they were unpredictable.</AbstractText> |
10,953 | Patient load effects on response time to critical arrhythmias in cardiac telemetry: a randomized trial. | Remotely monitored patients may be at risk for a delayed response to critical arrhythmias if the telemetry watchers who monitor them are subject to an excessive patient load. There are no guidelines or studies regarding the appropriate number of patients that a single watcher may safely and effectively monitor. Our objective was to determine the impact of increasing the number of patients monitored on response time to simulated cardiac arrest.</AbstractText>Randomized trial.</AbstractText>Laboratory-based experiment.</AbstractText>Forty-two remote telemetry technicians and nurses from cardiac units.</AbstractText>Number of patients monitored in a simulation of cardiac telemetry monitoring work.</AbstractText>We carried out a study to compare response times to ventricular fibrillation across five patient loads: 16, 24, 32, 40, and 48 patients. The simulation replicated the work of telemetry watchers using a combination of real recorded patient electrocardiogram signals and a simulated patient experiencing ventricular fibrillation. Study participants were assigned to one of the five patient loads and completed a 4-hour monitoring session, during which they performed tasks-including event documentation and phone calls to report events-similar to real monitoring work. When the simulated patient sustained ventricular fibrillation, the time required to report this arrhythmia was recorded. As patient loads increased, there was a statistically significant increase in response times to the ventricular fibrillation. In addition, frequency of failure to meet a response time goal of less than 20 seconds was significantly higher in the 48-patient condition than in all other conditions. Task performance decreased as patient load increased.</AbstractText>As participants monitored more patients in a laboratory setting, their performance with respect to recognizing critical and noncritical events declined. This study has implications for the design of remote telemetry work and other patient monitoring tasks in critical and intermediate care units.</AbstractText> |
10,954 | Trigger elimination of polymorphic ventricular tachycardia and ventricular fibrillation by catheter ablation: trigger and substrate modification. | Ventricular fibrillation (VF) is a malignant arrhythmia, usually initiated by a ventricular premature contraction (VPC) during the vulnerable period of cardiac repolarization. Ablation therapy for VF has been described and increasingly reported. Targets for VF triggers are VPCs preceded by Purkinje potentials or from the right ventricular outflow tract (RVOT) in structurally normal hearts, and VPC triggers preceded by Purkinje potentials in ischemic cardiomyopathy. During the session, mapping should be focused on the earliest activation and determining the earliest potential is the key to a successful ablation. However, suppression of VF can be achieved by not only the elimination of triggering VPCs, but also by substrate modification of possible reentry circuits in the Purkinje network, or between the PA and RVOT. The most important issue before the ablation session is the recording of the 12-lead ECG of the triggering event, which can prove invaluable in regionalizing the origin of the triggering VPC for more detailed mapping. In cases where the VPC is not spontaneous or inducible, ablation may be performed by pace mapping. Further studies are needed to evaluate the precise mechanisms of this arrhythmia. |
10,955 | Optimal antiarrhythmic drug therapy for electrical storm. | Electrical storm, defined as 3 or more separate episodes of ventricular tachycardia or ventricular fibrillation within 24 hours, carries significant morbidity and mortality. These unstable ventricular arrhythmias have been described with a variety of conditions including ischemic heart disease, structural heart disease, and genetic conditions. While implantable cardioverter defibrillator implantation and ablation may be indicated and required, antiarrhythmic medication remains an important adjunctive therapy for these persons. |
10,956 | Time-dependent risk reduction of ventricular tachyarrhythmias in cardiac resynchronization therapy patients: a MADIT-RIT sub-study. | Data on the time-dependent benefit of cardiac resynchronization therapy with defibrillator (CRT-D) compared with a dual-chamber implantable cardioverter-defibrillator (ICD) to reduce death or ventricular tachycardia (VT) or ventricular fibrillation (VF) are limited. We aimed to evaluate the time-related risk of death or sustained VT or VF in patients receiving CRT-D vs. ICD in the MADIT-RIT trial.</AbstractText>Kaplan-Meier survival analyses and multivariate Cox regression models were utilized to compare the incidence and the risk of death or sustained VT/VF in the CRT-D and ICD subgroups by the elapsed time after device implantation (6 months). Of the ICD (n = 742) and CRT-D (n = 757) patients enrolled, the risk of death was lower in CRT-D vs. in ICD early after device implantation [hazard ratio (HR) = 0.42, 95% confidence interval (CI): 0.17-1.03, P = 0.058] and beyond 6 months of follow-up (HR = 0.39, 95% CI: 0.21-0.73, P = 0.004), with the 6-month interaction P = 0.899. The overall risk of sustained VT/VF was reduced in CRT-D vs. ICD patients (HR = 0.73, 95% CI: 0.52-1.03, P = 0.07). However, the risk was similar in the first 6 months (HR = 1.00, 95% CI: 0.62-1.62, P = 0.988), and a lower risk emerged 6 months after CRT-D implantation (HR = 0.58, 95% CI: 0.38-0.88, P = 0.011), with the 6-month interaction P = 0.059.</AbstractText>The reduced mortality risk of CRT-D compared with an ICD alone began early after device implantation and was sustained during long-term follow-up; the reduced risk for ventricular tachyarrhythmias did not emerge until 6 months after device implantation.</AbstractText>http://clinicaltrials.gov/ct2/show/NCT00947310.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
10,957 | Vectorcardiography for optimization of stimulation intervals in cardiac resynchronization therapy. | Current optimization of atrioventricular (AV) and interventricular (VV) intervals in cardiac resynchronization therapy (CRT) is time consuming and subject to noise. We aimed to prove the principle that the best hemodynamic effect of CRT is achieved by cancelation of opposing electrical forces, detectable from the QRS morphology in the 3D vectorcardiogram (VCG). Different degrees of left (LV) and right ventricular (RV) pre-excitation were induced, using variation in AV intervals during LV pacing in 20 patients with left bundle branch block (LBBB) and variation in VV intervals during biventricular pacing in 18 patients with complete AV block or atrial fibrillation. The smallest QRS vector area identified stimulation intervals with minimal systolic stretch (median difference [IQR] 20 ms [-20, 20 ms] and maximal hemodynamic response (10 ms [-20, 40 ms]). Reliability of VCG measurements was superior to hemodynamic measurements. This study proves the principle that VCG analysis may allow easy and reliable optimization of stimulation intervals in CRT patients. |
10,958 | Critical takotsubo cardiomyopathy complicated by ventricular septal perforation. | An 81-year-old woman was admitted with chest pain. An electrocardiogram demonstrated ST segment elevation in leads II, III and aVF, and echocardiography revealed left ventricular apical asynergy with a left-to-right ventricular shunt. Meanwhile, emergent coronary angiography showed no significant coronary artery stenosis, whereas left ventriculography indicated apical ballooning and a left-to-right ventricular shunt. We therefore diagnosed the patient with Takotsubo cardiomyopathy complicated by ventricular septal perforation and cardiogenic shock. An electrocardiogram disclosed a prolonged QT interval over time, and the patient became hemodynamically stable under treatment with inotropes; however, she suddenly developed fatal ventricular fibrillation three days after hospitalization. Takotsubo cardiomyopathy complicated by ventricular septal perforation is a critical condition that requires careful monitoring. |
10,959 | Tracking rotors with minimal electrodes: modulation index-based strategy. | High-frequency periodic sources during cardiac fibrillation can be detected by phase mapping techniques. To enable practical therapeutic options for modulating periodic sources (existing techniques require high density multielectrode arrays and real time simultaneous mapping capability), a method to identify electrogram morphologies colocalizing to rotors that can be implemented on few electrograms needs to be devised.</AbstractText>Multichannel ventricular fibrillation electrogram data from 7 isolated human hearts using Langendorff setup and intraoperative clinical data from 2 human hearts were included in the analysis. The spatial locations of rotors were identified using phase maps constructed from 112 electrograms. Electrograms were analyzed for repeating patterns and discriminating signal morphologies around the locations of rotors and nonrotors were identified and quantified. Features were extracted from the unipolar electrogram patterns, which corroborated well with the spatial location of rotors. The results suggest that using the proposed modulation index feature, and as low as 1 sample point in the vicinity of the rotors, an accuracy as high as 86% (P<0.001) was obtained in separating rotor locations versus nonrotor locations. The analysis of bipolar electrogram signatures in the vicinity of the rotor locations suggest that 62.5% of the rotors occur at locations where the bipolar electrogram demonstrates continuous activities during ventricular fibrillation.</AbstractText>Unipolar electrogram extracted modulation index-based detection of rotors is feasible with few electrodes and has greater detection rate than bipolar approach. This strategy may be suitable for nonarray-based single mapping catheter enabled detection of rotors.</AbstractText>© 2015 American Heart Association, Inc.</CopyrightInformation> |
10,960 | DEGRO/DGK guideline for radiotherapy in patients with cardiac implantable electronic devices. | An increasing number of patients undergoing radiotherapy (RT) have cardiac implantable electronic devices [CIEDs, cardiac pacemakers (PMs) and implanted cardioverters/defibrillators (ICDs)]. Ionizing radiation can cause latent and permanent damage to CIEDs, which may result in loss of function in patients with asystole or ventricular fibrillation. Reviewing the current literature, the interdisciplinary German guideline (DEGRO/DGK) was developed reflecting patient risk according to type of CIED, cardiac condition, and estimated radiation dose to the CIED. Planning for RT should consider the CIED specifications as well as patient-related characteristics (pacing-dependent, previous ventricular tachycardia/fibrillation). Antitachyarrhythmia therapy should be suspended in patients with ICDs, who should be under electrocardiographic monitoring with an external defibrillator on stand-by. The beam energy should be limited to 6 (to 10) MV CIEDs should never be located in the beam, and the cumulative scatter radiation dose should be limited to 2 Gy. Personnel must be able to respond adequately in the case of a cardiac emergency and initiate basic life support, while an emergency team capable of advanced life support should be available within 5 min. CIEDs need to be interrogated 1, 3, and 6 months after the last RT due to the risk of latent damage. |
10,961 | The association between manual mode defibrillation, pre-shock pause duration and appropriate shock delivery when employed by basic life support paramedics during out-of-hospital cardiac arrest. | Pre-shock pause duration of <20s is associated with improved survival after cardiac arrest. Manual mode defibrillation has been associated with the shortest duration of pre-shock pause but is largely practiced by advanced life support paramedics (ALS) whereas defibrillator only paramedics (basic life support or BLS) routinely use the defibrillator in automatic mode.</AbstractText>We sought to explore the relationship between manual mode defibrillation, pre-shock pause duration and rate of inappropriate shocks when defibrillation is provided by ALS vs. BLS trained in manual mode defibrillation.</AbstractText>We performed a retrospective review of all treated non-traumatic adult out-of-hospital cardiac arrest (OHCA) presenting in a shockable rhythm over a one year period beginning January 1, 2012. Our primary outcome measure was the proportion of manual mode shocks delivered by BLS with pre-shock pause duration of <20s when compared to ALS. Our secondary outcome measures were the duration of pre-, post- and peri-shock pause and the proportion of appropriate shocks (defined as correct identification and shock delivery to patients in a shockable rhythm) delivered by either level of paramedic. This study had a power of 90% to detect an absolute difference of 15% between paramedic levels in proportion of shocks delivered with pre-shock pause duration <20s.</AbstractText>Among 2019 treated OHCA, 335 (20%) presented in a shockable rhythm. Manual defibrillation was performed in 155 (46%) of these cases (196 shocks by ALS, 143 shocks by BLS). There were no differences in the proportion of shocks delivered with pre-shock pause duration <20s (ALS 82.8% vs. BLS 84.8%, p=.65) nor pre-shock pause duration (s) (median, Q1, Q3); ALS: 12.0 (7.0,17.0) vs. BLS: 11.0 (5.0,17.0), p=.13 while BLS had a significantly shorter peri-shock pause duration (s) (median, Q1, Q3); ALS: 17.0 (12.0, 23.0) vs. BLS: 15.0 (9.0, 22.0), p=.05. There were no differences in the rate of inappropriate shocks (ALS 1.0% vs. BLS 0.7%), p=1.0 between levels of paramedics.</AbstractText>Manual mode defibrillation by BLS paramedics produced similar measures of pre-shock pause duration when compared to ALS paramedics without increasing the incidence of inappropriate shocks. Further study is required to determine the potential impact of BLS manual mode defibrillation on clinical outcomes.</AbstractText>Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
10,962 | [Results of pre-hospital cardiac resuscitation in the Reykjavik area 2004-2007]. | In the Reykjavik area, a physician staffed ambulance -responded to cardiac arrests from 1982-2007. The aim of this study was to assess the outcome of attempted pre-hospital cardiac resuscitations in the period from 2004-2007 and compare to previous studies.</AbstractText>All cases of attempted prehospital resuscitations in cardiac arrests of presumed cardiac etiology. Data was gathered according to the Utstein template.</AbstractText>Of a total of 289 cases in cardiac arrest, resuscitation was attempted in 279 and 200 of those were presumed to have a cardiac etiology. Men were 76% of the patients and the average age was 67.7 years. Average response time was 6.3 min. One hundred and seven (54%) survived to hospital admission and 50 (25%) survived to discharge compared to 16-19% in previous studies (p=0.16). The presenting rhythm was ventricular fibrillation/ventricular tachycardia (VF/VT) in 50% of the cases, 30% was in asystole and 20% in pulseless electrical activity (PEA). Of those admitted to intensive care unit/ department and had ventricular fibrillation on the first rhythm strip 70% were discharged during 2004-2007 compared to 49% during 1999-2002 (p=0.01). Bystander CPR was provided in 62% of witnessed cases compared to 54% in a previous study (p=0.26). One hundred and twenty (60%) were witnessed cases of which 37 (31%) survived to hospital discharge compared to 5 (8%)of non witnessed cases (p<0.01).</AbstractText>One in every four cardiac arrest patients in the Reykjavik area survives to discharge. This is similar to previous studies in the area (16-19%) and high compared to international studies 3-16%. Survival of those admitted to intensive care unit/ department and had ventricular fibrillation on the first rhythm strip was significantly higher compared to previous studies. Survival was found to be significantly higher if the cardiac arrest was witnessed.</AbstractText> |
10,963 | Beat-to-beat T-wave amplitude variability in the risk stratification of right ventricular outflow tract-premature ventricular complex patients. | Premature ventricular complexes (PVCs) originating from the right ventricular outflow tract (RVOT) may occasionally trigger monomorphic ventricular tachycardia (MVT), polymorphic ventricular tachycardia (PVT), or ventricular fibrillation (VF). We examined whether an analysis of the ventricular repolarization instability could differentiate PVT/VF triggered by RVOT-PVCs from benign RVOT-PVCs or MVT.</AbstractText>We evaluated the ventricular repolarization instability as assessed by the beat-to-beat T-wave amplitude variability (TAV) using Holter recordings in patients with RVOT-PVCs but with no structural heart disease. We determined the prematurity index, defined as the ratio of the coupling interval of the first ventricular tachycardia (VT) beat or isolated PVC to the preceding R-R interval just before the VT or isolated PVC in the Holter recordings. The study patients were classified into RVOT-PVCs/MVT (n = 33) and PVT/VF (n = 10).</AbstractText>The two groups did not differ with respect to the age, sex, and left ventricular ejection fraction. There was no significant difference in the prematurity index between the two groups (RVOT-PVCs/MVT 0.66 ± 0.16 vs. PVT/VF 0.61 ± 0.13, P = 0.60). The patients with PVT/VF had a significantly larger maximum TAV than those with RVOT-PVCs/MVT (31 ± 13 vs. 68 ± 40 µV, P < 0.001). Patients with a higher than median value of the TAV (33 µV) were at increased risk of PVT/VF vs. those with a lower than median value, after adjusting for the age and sex [9.25 (95% confidence interval: 1.27-19.2); P = 0.03].</AbstractText>The TAV analysis is a useful measure to identify the subset of usually benign RVOT-PVC/MVT patients prone to PVT/VF.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
10,964 | Heart rate is associated with progression of atrial fibrillation, independent of rhythm. | Atrial fibrillation (AF) often progresses from paroxysmal or persistent to more sustained forms, but the rate and predictors of AF progression in clinical practice are not well described.</AbstractText>Using the Outcomes Registry for Better Informed Treatment of AF, we analysed the incidence and predictors of progression and tested the discrimination and calibration of the HATCH (hypertension, age, TIA/stroke, chronic obstructive pulmonary disease, heart failure) and CHA₂DS₂VASc scores for identifying AF progression.</AbstractText>Among 6235 patients with paroxysmal or persistent AF at baseline, 1479 progressed, during follow-up (median 18 (IQR 12-24) months). These patients were older and had more comorbidities than patients who did not progress (CHADS₂ 2.3±1.3 vs 2.1±1.3, p<0.0001). At baseline, patients with AF progression were more often on a rate control as opposed to a rhythm control strategy (66 vs 56%, p<0.0001) and had higher heart rate (72(64-80) vs 68(60-76) bpm, p<0.0001). The strongest predictors of AF progression were AF on the baseline ECG (OR 2.30, 95% CI 1.95 to 2.73, p<0.0001) and increasing age (OR 1.16, 95% CI1.09 to 1.24, p<0.0001, per 10 increase), while patients with lower heart rate (OR 0.84, 95% CI 0.79 to 0.89, p<0.0001, per 10 decrease ≤80) were less likely to progress. There was no significant interaction between rhythm on baseline ECG and heart rate (p=0.71). The HATCH and CHA₂DS₂VASc scores had modest discriminatory power for AF progression (C-indices 0.55 (95% CI 0.53 to 0.58) and 0.55 (95% CI 0.52 to 0.57)).</AbstractText>Within 1.5 years, almost a quarter of the patients with paroxysmal or persistent AF progress to a more sustained form. Progression is strongly associated with heart rate, and age.</AbstractText>Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.</CopyrightInformation> |
10,965 | Stellate ganglion local anesthetic blockade and neurolysis for the treatment of refractory ventricular fibrillation. | Electrical storm (ES) is a syndrome characterized by recurrent ventricular fibrillation or tachycardia. It is a major clinical challenge and is often unresponsive to conventional drug therapy; instead, its treatment requires multiple attempts at electrical defibrillation. Sympathetic hyperactivity is an important modulator of ventricular arrhythmias, including ES. We report a case of ES treated safely and effectively with pharmacologic sympathectomy involving diagnostic continuous stellate ganglion blockade with local anesthetic followed by therapeutic neurolysis. This technique reduced ES in a patient for whom conservative medical and interventional procedures were ineffective. |
10,966 | Fibrosis: a structural modulator of sinoatrial node physiology and dysfunction. | Heart rhythm is initialized and controlled by the Sinoatrial Node (SAN), the primary pacemaker of the heart. The SAN is a heterogeneous multi-compartment structure characterized by clusters of specialized cardiomyocytes enmeshed within strands of connective tissue or fibrosis. Intranodal fibrosis is emerging as an important modulator of structural and functional integrity of the SAN pacemaker complex. In adult human hearts, fatty tissue and fibrosis insulate the SAN from the hyperpolarizing effect of the surrounding atria while electrical communication between the SAN and right atrium is restricted to discrete SAN conduction pathways. The amount of fibrosis within the SAN is inversely correlated with heart rate, while age and heart size are positively correlated with fibrosis. Pathological upregulation of fibrosis within the SAN may lead to tachycardia-bradycardia arrhythmias and cardiac arrest, possibly due to SAN reentry and exit block, and is associated with atrial fibrillation, ventricular arrhythmias, heart failure and myocardial infarction. In this review, we will discuss current literature on the role of fibrosis in normal SAN structure and function, as well as the causes and consequences of SAN fibrosis upregulation in disease conditions. |
10,967 | Miniaturized Reveal LINQ insertable cardiac monitoring system: First-in-human experience. | The Reveal LINQ is a miniaturized insertable cardiac monitor (ICM) with wireless telemetry for remote monitoring of patients with suspected arrhythmias.</AbstractText>The primary objective of this study was to evaluate the functionality of the Reveal LINQ system by measuring R-wave sensing and data transmission.</AbstractText>The Reveal LINQ Usability Study was a nonrandomized, prospective, multicenter trial. The study enrolled 30 patients with any indication for an ICM. Data were collected at baseline, implantation, and 1-month follow-up visits and through daily wireless transmissions.</AbstractText>Thirty patients were enrolled and had a Reveal LINQ device implanted. The mean age was 55 ± 15 years. All patients had successful implantation of the ICM in one of the recommended locations. Ease of implantation procedure was rated as easy or very easy for 90% of implantations. R-wave amplitudes were 0.584 ± 0.325 mV at implantation and 0.596 ± 0.336 mV at 1 month (P = .8). Automatic transmissions were successful 79.5% (69.5%-86.9%) of the time. Transmission failures that caused a delay in data transfer occurred because of incomplete data reception or patients being out of range in 45% and 42% of instances, respectively. For all patients, transmission failures were followed by successful automated or manual transmission of information on a subsequent day. The devices stored 217 arrhythmic episodes during 30 days of follow-up, identified as atrial fibrillation (n = 111), asystole (n = 95), bradycardia (n = 4), fast ventricular tachycardia (n = 1), and ventricular tachycardia ( n = 6). No serious procedure- or system-related adverse events occurred during the 1-month follow-up period.</AbstractText>The miniaturized Reveal LINQ ICM supports arrhythmia detection and monitoring, achieving adequate sensing performance without safety issues.</AbstractText>URL: http://www.clinicaltrials.gov. Unique identifier: NCT01965899.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,968 | Blood Pressure and Atrial Fibrillation: A Combined AF-CHF and AFFIRM Analysis. | Hypertension is an established risk factor for new-onset atrial fibrillation (AF). However, the relationship between blood pressure and recurrent AF is less well understood.</AbstractText>A pooled analysis of patient-level data from AFFIRM and AF-CHF trials was conducted on all 2,715 patients with paroxysmal or persistent AF, 68 ± 8 years, 66% male, randomized to rhythm control and followed for 40.6 ± 16.5 months. We assessed the impact of a baseline systolic blood pressure (SBP; <120 mmHg [N = 1,008], 120-140 mmHg [N = 930], >140 mmHg [N = 777]) on recurrent AF and proportion of time spent in AF. In patients with LVEF >40% (N = 1,719), SBP was not associated with recurrent AF in multivariate regression analyses (P = 0.752). In contrast, in patients with LVEF ≤40% (N = 996), the AF recurrence rate was higher in those with an SBP >140 mmHg compared to 120-140 mmHg (hazard ratio 1.47; 95% CI [1.12-1.93], P = 0.005). The rate of recurrent AF was similar in patients with SBP <120 mmHg compared to 120-140 mmHg (hazard ratio 1.15; 95% CI [0.92-1.43], P = 0.225). Consistently, the proportion of time spent in AF was not influenced by SBP in patients with LVEF >40% (P = 0.645). However, in patients with LVEF ≤40%, the adjusted mean proportion of time spent in AF was 17.2% if SBP was <120 mmHg, 15.4% for SBP 120-140 mmHg, and 24.0% for SBP >140 mmHg (P = 0.025).</AbstractText>Systolic blood pressure is an important determinant of recurrent AF and overall AF burden in patients with left ventricular dysfunction (LVEF≤40%) but not in those with preserved ventricular function.</AbstractText>© 2015 Wiley Periodicals, Inc.</CopyrightInformation> |
10,969 | Evaluating the effects of different dental devices on implantable cardioverter defibrillators. | The implantable cardioverter defibrillator (ICD) is an electronic device that emits electrical signals to the heart via lead wires and electrodes. It is used for cardiac rhythm monitoring and treatment. Because electronic dental devices have been shown to produce electromagnetic fields, we hypothesize that they may interfere with ICD function.</AbstractText>Nine dental devices (heat carrier, electronic apex locator, electric pulp tester, unipolar electrosurgery unit, electric motor, curing light, and 3 gutta-percha guns) were tested in this study for their ability to interfere with the function of 4 ICDs (2 single-chambered and 2 dual-chambered ICDs). ICD activity was monitored for 30 seconds using an ICD programmer (Medtronic 2090; Minneapolis, MN) and evaluated through an electrogram test strip printout.</AbstractText>Electromagnetic interference was detected with the electric motor, curing light, electric pulp tester, and electrosurgery unit although no electromagnetic disturbances were detected with these devices. No electromagnetic interferences were observed for the gutta-percha guns, heat carrier, and apex locator. However, the electrosurgery unit affected the dual-chambered ICD (Consulta CRT-D, Medtronic) and delivered therapies for fibrillation when no ventricular fibrillation was present.</AbstractText>Our results suggest that the electrosurgery unit produces electromagnetic disturbances with unwanted therapy delivery shock and potentially clinically significant outcomes.</AbstractText>Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,970 | [Detection of Signs of Thrombus Formation in Patients With Typical Atrial Flutter]. | to assess rate of detection of markers of thrombi formation and to determine whether transthoracic echocardiography data or clinical characteristics predict severe left atrial appendage [LAA] dysfunction (low LAA velocity, severe spontaneous echo contrast [SEC], LAA thrombus) in patients with typical atrial flutter (AFl).</AbstractText>Consecutive 406 patients (299 with atrial fibrillation [AFib] and 107 with AFl) underwent transesophageal echocardiography before cardioversion. Mean age was 59.3 years, mean CHA2DS2-VASc score- 1.86, mean LAA velocity - 37.02 cm/s.</AbstractText>Compared with patients with AF those with AFl had lower rate of detection of markers of thrombi formation (p<0.05). Among patients with AFl 1.8% had SEC grade 4+, 7.4% - LAA velocity less or equal 25 cm/s. LAA thrombus was found in 2.8 and 8.1% of patients with AFl and AFib, respectively. Prevalence of thrombi in left ventricular (LV) cavity was significantly higher inpatients with AFl (3.13 vs. 0.3% in patients with AFib, p=0.02). In patients with AFl systolic LV dysfunction was the main and ost significant predictor of severe LAA dysfunction and presence LV thrombus.</AbstractText>AFl associated high risk of embolic events is primarily determined by its adverse effect on LV function.</AbstractText> |
10,971 | Inconsistent shock advisories for monomorphic VT and Torsade de Pointes--A prospective experimental study on AEDs and defibrillators. | Cardiovascular disease and sudden cardiac arrest are the leading causes of death in the United States. Early defibrillation is key to successful resuscitation for patients who experience shockable rhythms during a cardiac arrest. It is therefore vital that the shock advisory of AEDs (automated external defibrillators) or defibrillators in AED mode be reliable and appropriate. The goal of this study was to better understand the performance of multiple lay-rescuer and hospital professional defibrillators in AED mode in their analysis of ventricular arrhythmias. The measurable objectives of this study sought to quantify: 1. No shock advisory for sinus rhythms at any rate. 2. Recognition and shock advisory for ventricular fibrillation (VF). 3. Recognition and shock advisory for monomorphic ventricular tachycardia (VT). 4. Recognition and shock advisory for Torsades de Pointes (TdP).</AbstractText>This is a prospective evaluation of two AEDs and four semi-automatic, hospital professional defibrillators. This study represents post-marketing evaluation of FDA approved devices. Each defibrillator was connected to multiple rhythm simulators and presented with simulated ECG waveforms 20 consecutive times at various rates when possible.</AbstractText>All four defibrillators and both AEDs tested consistently recognized normal sinus rhythm (NSR) from all rhythm sources, and did not recommend a shock for NSR at any rate (from 80 to 220 bpm). All four defibrillators and both AEDs recognized VF from all rhythm sources tested and recommended a shock 100% of the time. Variations were found in the shock advisory rates among defibrillators when testing simulated VT heart rates at or below 150 bpm. One AED tested did not consistently advise a shock for monomorphic VT or TdP at any tested rate.</AbstractText>Lay-rescuer AEDs and professional hospital defibrillators tested in AED mode did not reliably recommend a shock for sustained monomorphic VT or TdP at certain rates, despite the fact that it is a critical component of the currently recommended treatment. These findings require further examination of the risk benefit analysis of shocking or not shocking rhythms such as TdP or pulseless VT.</AbstractText>Published by Elsevier Ireland Ltd.</CopyrightInformation> |
10,972 | Successful Ablation of Single Reentrant Ventricular Tachycardia Arising from Peri-Aortic Scar in a Patient with an Apparently Normal Heart. | Peri-aortic region is one of the arrhythmogenic foci associated not only with idiopathic ventricular tachycardia (VT), but also scar-related VT in patients with an apparently normal heart.[1-3] A recent study reported that the patients with scar-related VT were significantly older, had a frequent history of hypertension, and inducibility of multiple monomorphic VTs compared to the patients with idiopathic VT.[2] However, whether these clinical features are the causes of the peri-aortic scar or innocent by-standers, remain uncertain. Here, we present a relatively young normotensive patient with a peri-aortic scar and emphasize the importance of cardiac MRI to detect latent arrhthmogenic substrates. |
10,973 | Idiopathic Ventricular Tachycardia: Transcatheter Ablation or Antiarrhythmic Drugs? | Ventricular tachycardia or frequent premature ventricular contractions (PVCs) can occur in the absence of any detectable structural heart disease. In this clinical setting, these arrhythmias are termed idiopathic. Usually, they carry a benign prognosis and any potential ablative intervention is carried out if patients are highly symptomatic or, more importantly, if frequent ventricular arrhythmias can lead to ventricular dysfunction.</AbstractText>In this paper, different forms of idiopathic ventricular tachycardia are reviewed. Outflow tract ventricular tachycardia from the right ventricle is the most frequent form of the so-called idiopathic ventricular tachycardia. Other forms of idiopathic ventricular arrhythmias include ventricular tachycardia/PVCs arising from tricuspid annulus, from the mitral annulus, inter-fascicular ventricular tachycardia and papillary muscle ventricular tachycardia. When interventional treatment is deemed necessary, detailed mapping ( earliest activation during VT/PVC, pace mapping ) is crucial as to identify the successful ablation site. Catheter ablation more than antiarrhythmic drug treatment is usually highly effective in eliminating idiopathic ventricular arrhythmias and providing prevention of recurrence.</AbstractText>Idiopathic VTs are not considered life-threatening arrhythmias and, prevention of recurrences is often achieved by means of catheter ablation that provides an improvement of quality of life. The overall acute success rate of catheter ablation is about 85-90% with a long-term prevention of arrhythmia recurrence of about 75-80%. It is advisable that the procedure is carried out by electrophysiologists with expertise in VT catheter ablation and extensive knowledge of cardiac anatomy as to ensure a high success rate and reduce the likelihood of major complications.</AbstractText> |
10,974 | Vagus nerve stimulation reverses ventricular electrophysiological changes induced by hypersympathetic nerve activity. | What is the central question of this study? Previous studies have shown that hypersympathetic nerve activity results in ventricular electrophysiological changes and facilitates the occurrence of ventricular arrhythmias. Vagus nerve stimulation has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. However, the actions of vagus nerve stimulation on hypersympathetic nerve activity-induced ventricular electrophysiological changes are still unknown. What is the main finding and its importance? We show that vagus nerve stimulation is able to reverse hypersympathetic nerve activity-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation. These findings further suggest that vagus nerve stimulation may be an effective treatment option for ventricular arrhythmias, especially in patients with myocardial infarction or heart failure. Vagus nerve stimulation (VNS) has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. This study aimed to investigate the effects of VNS on ventricular electrophysiological changes induced by hypersympathetic nerve activity. Seventeen open-chest dogs were subjected to left stellate ganglion stimulation (LSGS) for 4 h to simulate hypersympathetic tone. All animals were randomly assigned to the VNS group (n = 9) or the control group (n = 8). In the VNS group, VNS was performed at the voltage causing a 10% decrease in heart rate for hours 3-4 during 4 h of LSGS. During the first 2 h of LSGS, the ventricular effective refractory period (ERP) and action potential duration (APD) were both progressively and significantly decreased; the spatial dispersion of ERP, maximal slope of the restitution curve and pacing cycle length of APD alternans were all increased. With LSGS + VNS during the next 2 h, there was a significant return of all the altered electrophysiological parameters towards baseline levels. In the eight control dogs that received 4 h of LSGS without VNS, all the parameters changed progressively, but without any reversals. The ventricular fibrillation threshold was higher in the VNS group than in the control group (17.3 ± 3.4 versus 11.3 ± 3.8 V, P < 0.05). The present study demonstrated that VNS was able to reverse LSGS-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation. |
10,975 | P wave analysis and left ventricular systolic function in chronic heart failure. Possible insights form the P wave - PP interval spectral coherence. | Chronic increase in left ventricular filling pressure represents one of the most important mechanism underlying the structural, as well as the electrical, atrial chamber remodeling leading to atrial fibrillation. The present pilot pathophysiological study sought to investigate possible relationship between short-period cross-spectral coherence of P-Q, R-R and P-P intervals and echocardiographic indices of left ventricular and atrial function.</AbstractText>Electrocardiographic single lead short-term cross-spectral analysis on P-Q and P-P intervals was performed in 31 patients with chronic heart failure (CHF). Twenty age and therapy matched hypertensive patients acted as control group. The interval between the beginning of P wave and its peak (Ppeak) was also analyzed.</AbstractText>Patients with CHF showed a significant lower PQ → PP and Ppeak → PP coherence (P<0.001) than the counterpart. At multivariate analysis only Ppeak → PP was independently associated to LVEF (r2:0.312; b:60; β:0.559; P<0.0001) and atrial volume (r2:-0.160; b:-0.15; β:-0.400, P<0.05).</AbstractText>Ppeak → PP coherence might be a simple marker of left ventricular and atrial function. Whether this index could be a useful noninvasive marker of increased left ventricular filling pressure and, possibly, of atrial fibrillation risk or not, it needs to be tested in larger prospective studies.</AbstractText> |
10,976 | Flecainide: Current status and perspectives in arrhythmia management. | Flecainide acetate is a class IC antiarrhythmic agent and its clinical efficacy has been confirmed by the results of several clinical trials. Nowadays, flecainide is recommended as one of the first line therapies for pharmacological conversion as well as maintenance of sinus rhythm in patients with atrial fibrillation and/or supraventricular tachycardias. Based on the Cardiac Arrhythmia Suppression Trial study results, flecainide is not recommended in patients with structural heart disease due to high proarrhythmic risk. Recent data support the role of flecainide in preventing ventricular tachyarrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia associated both with ryanodine receptor and calsequestrin mutations. We herein review the current clinical data related to flecainide use in clinical practice and some concerns about its role in the management of patients with coronary artery disease. |
10,977 | Acute anti-fibrillating and defibrillating potential of atorvastatin, melatonin, eicosapentaenoic acid and docosahexaenoic acid demonstrated in isolated heart model. | Cardioprotective compounds such as atorvastatin, melatonin, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) exhibit antiarrhythmic potential in clinical and/or experimental conditions but underlying mechanisms are poorly understood. We have previously shown that protection from ventricular fibrillation (VF) due to prolonged treatment with these compounds was linked with modulation of myocardial connexin-43, which is responsible for myocardial electrical coupling and synchronisation. To elucidate further the antiarrhythmic potential of atorvastatin, melatonin, EPA and DHA we aimed to explore their acute anti-fibrillating effects and defibrillating efficacy. Experiments were conducted on isolated perfused heart preparation of adult male and female hypertriglyceridemic (HTG) rats when using atorvastatin, EPA and DHA, while melatonin was examined in hearts of old male and female guinea pigs. VF inducibility was tested in hearts pre-treated for 10 min with atorvastatin, EPA or DHA (15 μmol) or melatonin (50 μmol) and compared with non-pre-treated hearts. Sustained VF was induced in all untreated HTG rat hearts. In contrast, its incidence was reduced to 30% and 60% by atorvastatin, 70% and 75% by EPA, 60% and 60% by DHA in male or female rat hearts respectively. Moreover, bolus (150 μmol) of EPA and DHA administered directly to the fibrillating heart restored sinus rhythm in 6 of 6 hearts and atorvastatin in 4 of 6 hearts. Threshold to induce sustained VF was 21.7 ± 3.8 mA in male and 38.3 ± 2.9 mA in female guinea pig hearts. However, sustained VF was not possible to induce even by the strongest (50 mA) stimulus in the heart pre-treated with melatonin regardless the sex. In conclusion, atorvastatin, melatonin, EPA and DHA exhibit clear cut acute anti-fibrillating efficacy. Findings challenge to investigate expression of connexin-43, especially its phosphorylated status associated with connexin channel function, in acute conditions. |
10,978 | The association of health status and providing consent to continued participation in an out-of-hospital cardiac arrest trial performed under exception from informed consent. | Emergency medical research performed under federal regulation 21 § CFR 50.24 provides a means to protect human subjects and investigate novel time-sensitive treatments. Although prospective individual consent is not required for studies conducted under this regulation, consent from a legally authorized representative (LAR) or the patient at the earliest feasible opportunity is required to obtain short- and long-term outcome data. The objective of this study was to determine which demographic, cardiac arrest, and patient outcome characteristics predicted the likelihood of obtaining informed consent following enrollment under exception from informed consent in a multicenter cardiac arrest study.</AbstractText>This investigation was an analysis of data collected during a multisite, randomized, controlled, out-of-hospital cardiac arrest clinical trial performed under 21 § CFR 50.24. Research personnel attempted to obtain informed consent from LARs and subjects for medical records review of primary outcome data, as well as consent for neurologic outcome assessments up to 1 year post-cardiac arrest. Hospital discharge and neurologic status were obtained from public records and/or medical records up until the time consent was formally denied, in accordance with federal regulations and guidance. Local institutional review boards also allowed medical records review for cases where consent was neither obtained nor declined despite multiple consent attempts. Patient demographic, cardiac arrest, and clinical outcome characteristics were analyzed in univariate multinomial regression models, with consent status (obtained, denied, neither obtained nor denied) as the dependent variable. A multivariate multinomial logistic regression was then performed. An exploratory secondary analysis following the same process was performed after assigning patients who neither consented nor declined to the declined consent group.</AbstractText>Among a total study population of 1,655 cardiac arrest subjects, 457 were transported and had consent attempted (27.6%). The survival status and neurologic function at the time of hospital discharge were known in 440 of 457 (96%) subjects. In the multivariate analysis, initial rhythm of ventricular fibrillation/ventricular tachycardia (VF/VT) and survival with good neurologic outcome were strong predictors of obtaining consent (odds ratio [OR] = 3.15, 95% confidence interval [CI] = 1.73 to 5.75; OR = 7.64, 95% CI = 2.28 to 25.63, respectively). The exploratory secondary analysis also showed initial rhythm of VF/VT and survival with good neurologic outcome as strong predictors of obtaining consent (OR = 1.86, 95% CI = 1.17 to 2.95; OR = 4.52, 95% CI = 2.21 to 9.26, respectively).</AbstractText>Initial arrest rhythm and survival with good neurologic outcome were highly predictive of obtaining consent in this cardiac arrest trial. This phenomenon could result in underrepresentation of outcome data in the study arm with the worse outcome and represents a significant potential confounder in studies performed under 21 § CFR 50.24. Future revisions to the exception from informed consent regulations should allow access to critical survival data recorded as part of standard documentation, regardless of patient consent status.</AbstractText>© 2015 by the Society for Academic Emergency Medicine.</CopyrightInformation> |
10,979 | Cardioverter defibrillator implantation without induction of ventricular fibrillation: a single-blind, non-inferiority, randomised controlled trial (SIMPLE). | Defibrillation testing by induction and termination of ventricular fibrillation is widely done at the time of implantation of implantable cardioverter defibrillators (ICDs). We aimed to compare the efficacy and safety of ICD implantation without defibrillation testing versus the standard of ICD implantation with defibrillation testing.</AbstractText>In this single-blind, randomised, multicentre, non-inferiority trial (Shockless IMPLant Evaluation [SIMPLE]), we recruited patients aged older than 18 years receiving their first ICD for standard indications at 85 hospitals in 18 countries worldwide. Exclusion criteria included pregnancy, awaiting transplantation, particpation in another randomised trial, unavailability for follow-up, or if it was expected that the ICD would have to be implanted on the right-hand side of the chest. Patients undergoing initial implantation of a Boston Scientific ICD were randomly assigned (1:1) using a computer-generated sequence to have either defibrillation testing (testing group) or not (no-testing group). We used random block sizes to conceal treatment allocation from the patients, and randomisation was stratified by clinical centre. Our primary efficacy analysis tested the intention-to-treat population for non-inferiority of no-testing versus testing by use of a composite outcome of arrhythmic death or failed appropriate shock (ie, a shock that did not terminate a spontaneous episode of ventricular tachycardia or fibrillation). The non-inferiority margin was a hazard ratio (HR) of 1·5 calculated from a proportional hazards model with no-testing versus testing as the only covariate; if the upper bound of the 95% CI was less than 1·5, we concluded that ICD insertion without testing was non-inferior to ICD with testing. We examined safety with two, 30 day, adverse event outcome clusters. The trial is registered with ClinicalTrials.gov, number NCT00800384.</AbstractText>Between Jan 13, 2009, and April 4, 2011, of 2500 eligible patients, 1253 were randomly assigned to defibrillation testing and 1247 to no-testing, and followed up for a mean of 3·1 years (SD 1·0). The primary outcome of arrhythmic death or failed appropriate shock occurred in fewer patients (90 [7% per year]) in the no-testing group than patients who did receive it (104 [8% per year]; HR 0·86, 95% CI 0·65-1·14; pnon-inferiority <0·0001). The first safety composite outcome occurred in 69 (5·6%) of 1236 patients with no-testing and in 81 (6·5%) of 1242 patients with defibrillation testing, p=0·33. The second, pre-specified safety composite outcome, which included only events most likely to be directly caused by testing, occurred in 3·2% of patients with no-testing and in 4·5% with defibrillation testing, p=0·08. Heart failure needing intravenous treatment with inotropes or diuretics was the most common adverse event (in 20 [2%] of 1236 patients in the no-testing group vs 28 [2%] of 1242 patients in the testing group, p=0·25).</AbstractText>Routine defibrillation testing at the time of ICD implantation is generally well tolerated, but does not improve shock efficacy or reduce arrhythmic death.</AbstractText>Boston Scientific and the Heart and Stroke Foundation (Ontario Provincial office).</AbstractText>Copyright © 2015 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
10,980 | Biomarkers in electrophysiology: role in arrhythmias and resynchronization therapy. | Circulating biomarkers related to inflammation, neurohormones, myocardial stress, and necrosis have been associated with commonly encountered arrhythmic disorders such as atrial fibrillation (AF) and more malignant processes including ventricular arrhythmias (VA) and sudden cardiac death (SCD). Both direct and indirect biomarkers implicated in the heart failure cascade have potential prognostic value in patients undergoing cardiac resynchronization therapy (CRT). This review will focus on the role of biomarkers in AF, history of SCD, and CRT with an emphasis to improve clinical risk assessment for arrhythmias and patient selection for device therapy. Notably, information obtained from biomarkers may supplement traditional diagnostic and imaging techniques, thus providing an additional benefit in the management of patients. |
10,981 | Etiology-specific assessment of predictors of long-term survival in chronic systolic heart failure. | We sought to identify prognostic factors of long-term mortality, specific for the underlying etiology of chronic systolic heart failure (CHF).</AbstractText>Between 1995 and 2009 baseline characteristics, treatment and follow-up data from 2318 CHF-patients due to ischemic (ICM; 1100 patients) or dilated cardiomyopathy (DCM; 1218 patients) were prospectively compared. To calculate hazard ratios with 95%-confidence intervals cox regression was used. We respectively established etiology-specific multivariable models of independent prognostic factors. During the follow-up period of up to 14.8 years (mean = 53.1 ± 43.5 months; 10,264 patient-years) 991 deaths (42.8%) occurred. In the ICM-cohort, 5-year-survival was 53.4% (95% CI: 49.9-56.7%), whereas in DCM-patients it was higher (68.1% (95% CI: 65.1-71.0%)). Age, ejection fraction, or hyponatremia were independent predictors for mortality in both cohorts, whereas diabetes, COPD, atrial fibrillation and a heart rate of ≥ 80/min carried independent predictive power only in ICM-patients.</AbstractText>This study demonstrates the disparity of prognostic value of clinically derived risk factors between the two main causes of CHF. The effects of covariables in DCM-patients were lower, suggesting a less modifiable disease through risk factors considering mortality risk. An etiology-specific prognostic model may improve accuracy of survival estimations in CHF.</AbstractText> |
10,982 | β-Adrenergic stimulation and rapid pacing mutually promote heterogeneous electrical failure and ventricular fibrillation in the globally ischemic heart. | Global ischemia, catecholamine surge, and rapid heart rhythm (RHR) due to ventricular tachycardia or ventricular fibrillation (VF) are the three major factors of sudden cardiac arrest (SCA). Loss of excitability culminating in global electrical failure (asystole) is the major adverse outcome of SCA with increasing prevalence worldwide. The roles of catecholamines and RHR in the electrical failure during SCA remain unclear. We hypothesized that both β-adrenergic stimulation (βAS) and RHR accelerate electrical failure in the globally ischemic heart. We performed optical mapping of the action potential (OAP) in the right ventricular (RV) and left (LV) ventricular epicardium of isolated rabbit hearts subjected to 30-min global ischemia. Hearts were paced at a cycle length of either 300 or 200 ms, and either in the presence or in the absence of β-agonist isoproterenol (30 nM). 2,3-Butanedione monoxime (20 mM) was used to reduce motion artifact. We found that RHR and βAS synergistically accelerated the decline of the OAP upstroke velocity and the progressive expansion of inexcitable regions. Under all conditions, inexcitability developed faster in the LV than in the RV. At the same time, both RHR and βAS shortened the time to VF (TVF) during ischemia. Moreover, the time at which 10% of the mapped LV area became inexcitable strongly correlated with TVF (R(2) = 0 .72, P < 0.0001). We conclude that both βAS and RHR are major factors of electrical depression and failure in the globally ischemic heart and may contribute to adverse outcomes of SCA such as asystole and recurrent/persistent VF. |
10,983 | Implantable cardioverter-defibrillator therapy in patients with ventricular fibrillation out of hospital cardiac arrest secondary to acute coronary syndrome. | Survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) due to a potentially reversible cause such as acute myocardial infarction (MI) or ischemia are considered to be at low risk of recurrent arrhythmia. Implantable cardioverter defibrillators (ICD) are not routinely recommended in such patients. However, the outcome of these patients in the era of rapid coronary revascularization and ICD therapy is not known.</AbstractText>We examined the outcome of 114 consecutive survivors of VF OHCA due to acute MI or ischemia in Olmsted County, MN from 1990 to 2011. An ICD was implanted in 45/114 patients. ICD recipients had lower EF [median (IQR) 38 (26 to 54) versus 48 (35 to 58) %, P=0.04]. During a median (IQR) follow-up of 9.9 (4.4 to 14.6) years, ICD implantation was associated with reduced cardiac mortality (HR 0.24 [0.07 to 0.88], P=0.031) and a trend towards reduced all-cause mortality (HR 0.56 [0.30 to 1.02], P=0.059) after adjusting for the first principal component. One or more appropriate ICD therapies were delivered in 19/45, with half of the patients receiving therapy within 1 year. Patients with EF ≤35% at discharge continued to be at long-term risk for ICD therapy compared with those with EF >35% who were at increased risk predominantly in the first 8 months. EF and revascularization were not significantly associated with ICD therapy in the multivariable analysis.</AbstractText>Patients with VF-OHCA in the setting of acute MI or myocardial ischemia remain at high risk of recurrent ventricular arrhythmias, particularly if EF ≤35%. This suggests that ICD implantation may be reasonable if EF ≤35%.</AbstractText>© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.</CopyrightInformation> |
10,984 | Dronedarone and digitalis: individually reduced post-repolarization refractoriness enhances life-threatening arrhythmias. | Interaction between dronedarone and digitalis has been discussed as a possible cause for increased mortality in the presence of dronedarone observed in the PALLAS trial. The aim of this study was to assess possible proarrhythmic effects of dronedarone in combination with digitalis in an experimental whole heart model.</AbstractText>Twenty-six female rabbits underwent chronic oral treatment with dronedarone (50 mg/kg/day for 6 weeks). Twenty-four rabbits received placebo. Heart failure was induced by rapid ventricular pacing. Sham-operated rabbits received a right-ventricular pacing lead but were not paced. Thereafter, hearts were isolated and Langendorff-perfused. Monophasic action potentials and a 12 lead electrocardiogram showed a dose-dependent decrease of QT interval, APD90, effective refractory periods, and postrepolarization refractoriness in control hearts and dronedarone-pretreated hearts after application of ouabain (0.1 and 0.2 µM). After acute application of ouabain, ventricular fibrillation (VF) was inducible by programmed ventricular stimulation in 6 of 12 untreated sham hearts (38 episodes) as compared with 7 of 11 dronedarone-pretreated sham hearts (76 episodes). In untreated failing hearts, 6 of 12 hearts were inducible (47 episodes) as compared with 7 of 15 hearts dronedarone-pretreated failing hearts (93 episodes).</AbstractText>In this study, ouabain treatment resulted in an increased ventricular vulnerability in chronically dronedarone-pretreated control and failing hearts. Ouabain led to a significant abbreviation of ventricular repolarization. This was more marked in dronedarone-pretreated hearts and resulted in an elevated incidence of VF. This may help to interpret the results of the PALLAS trial.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
10,985 | The effect of C-reactive protein reduction with a highly specific antisense oligonucleotide on atrial fibrillation assessed using beat-to-beat pacemaker Holter follow-up. | C-reactive protein (CRP) is known to be strongly associated with atrial fibrillation (AF). However, it is not clear if CRP is a causal factor for AF. ISIS-CRPRx is a novel antisense oligonucleotide that reduces CRP production by specifically inhibiting mRNA translation. The effect of ISIS-CRPRx on AF was evaluated.</AbstractText>A double-blind phase II trial of ISIS-CRPRx in patients with paroxysmal AF and DDDRP permanent pacemakers (PPMs) with advanced atrial and ventricular Holters allowing beat-to-beat arrhythmia follow-up.</AbstractText>Twenty six patients were screened and seven patients dosed with ISIS-CRPRx. After 4 weeks of baseline assessment, patients were randomly assigned to two treatment periods of either placebo then ISIS-CRPRx or ISIS-CRPRx then placebo. All patients were followed up for 8 weeks after the active treatment period. There was a 63.7 % (95 % CI 38.4 to 78.6 %, p = 0.003) relative reduction in CRP on treatment with ISIS-CRPRx versus baseline. Sensitivity analyses demonstrated a consistent treatment effect. The primary end-point was change in AF burden assessed by PPM. There was no significant difference in AF burden on treatment with ISIS-CRPRx versus baseline (OR 1.6, 95 % CI -2.42 to 5.62, p = 0.37). ISIS CRPRx was safe and well tolerated and there were no serious adverse events.</AbstractText>Treatment with ISIS-CRPRx did not reduce AF burden in patients with paroxysmal AF and PPMs, despite a large relative reduction in CRP. In this population, highly specific CRP reduction had no clinically discernable effect upon paroxysmal AF. However, average levels of CRP at baseline were relatively low, so it remains possible that AF patients with higher levels of CRP may benefit from CRP-directed therapy.</AbstractText> |
10,986 | Relation between cancer and atrial fibrillation (from the REasons for Geographic And Racial Differences in Stroke Study). | Atrial fibrillation (AF) is common in patients with life-threatening cancer and those undergoing active cancer treatment. However, data from subjects with a history of non-life-threatening cancer and those who do not require active cancer treatment are lacking. A total of 15,428 (mean age 66 ± 8.9 years; 47% women; 45% blacks) participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study with baseline data on previous cancer diagnosis and AF were included. Participants with life-threatening cancer and active cancer treatment within 2 years of study enrollment were excluded. History of cancer was identified using computer-assisted telephone interviews. AF cases were identified from baseline electrocardiogram data and by a self-reported history of a previous diagnosis. Logistic regression was used to examine the cross-sectional association between cancer diagnosis and AF. A total of 2,248 (15%) participants had a diagnosis of cancer and 1,295 (8.4%) had AF. In a multivariable logistic regression model adjusted for sociodemographic characteristics (age, gender, race, education, income, and region of residence) and cardiovascular risk factors (systolic blood pressure, high-density lipoprotein cholesterol, total cholesterol, C-reactive protein, body mass index, smoking, diabetes, antihypertensive and lipid-lowering agents, left ventricular hypertrophy, and cardiovascular disease), those with cancer were more likely to have prevalent AF than those without cancer (odds ratio 1.19, 95% confidence interval 1.02 to 1.38). Subgroup analyses by age, sex, race, cardiovascular disease, and C-reactive protein yielded similar results. In conclusion, AF was more prevalent in participants with a history of non-life-threatening cancer and those who did not require active cancer treatment in REGARDS. |
10,987 | Insulation Failure of the Linox Defibrillator Lead: A Case Report and Retrospective Review of a Single Center Experience. | Implantable cardioverter defibrillator (ICD) lead insulation failure and conductor externalization have been increasingly reported. The 7.8F silicon-insulated Linox SD and Linox S ICD leads (Biotronik, Berlin, Germany) were released in 2006 and 2007, respectively, with an estimated 85,000 implantations worldwide. A 39-year-old female suffered an out-of-hospital ventricular fibrillation (VF) arrest with successful resuscitation. An ICD was implanted utilizing a single coil active fixation Linox(Smart) S lead (Biotronik, Berlin, Germany). A device-triggered alert approximately 3 years after implantation confirmed nonphysiological high rate sensing leading to VF detection. A chest X-ray showed an abnormality of the ICD lead and fluoroscopic screening confirmed conductor externalization proximal to the defibrillator coil. In view of the combined electrical and fluoroscopic abnormalities, urgent lead extraction and replacement were performed. A review of Linox (Biotronik) and Vigila (Sorin Group, Milan, Italy) lead implantations within our center (n = 98) identified 3 additional patients presenting with premature lead failure, 2 associated with nonphysiological sensed events and one associated with a significant decrease in lead impedance. All leads were subsequently removed and replaced. This case provides a striking example of insulation failure affecting the Linox ICD lead and, we believe, is the first to demonstrate conductor externalization manifesting both electrical and fluoroscopic abnormalities. |
10,988 | Effect and mechanism of fluoxetine on electrophysiology in vivo in a rat model of postmyocardial infarction depression. | Major depression is diagnosed in 18% of patients following myocardial infarction (MI), and the antidepressant fluoxetine is shown to effectively decrease depressive symptoms and improve coronary heart disease prognosis. We observed the effect of fluoxetine on cardiac electrophysiology in vivo in a rat model of post-MI depression and the potential mechanism.</AbstractText>Eighty adult male Sprague Dawley rats (200-250 g) were randomly assigned to five groups: normal control (control group), MI (MI group), depression (depression group), post-MI depression (model group), and post-MI depression treated with intragastric administration of 10 mg/kg fluoxetine (fluoxetine group). MI was induced by left anterior descending coronary artery ligation. Depression was developed by 4-week chronic mild stress (CMS). Behavior measurement was done before and during the experiment. Electrophysiology study in vivo and Western blot analysis were carried on after 4 weeks of CMS. After 4 weeks of CMS, depression-like behaviors were observed in the MI, depression, and model groups, and chronic fluoxetine administration could significantly improve those behaviors (P<0.05 vs model group). Fluoxetine significantly increased the ventricular fibrillation threshold compared with the model group (20.20±9.32 V vs 14.67±1.85 V, P<0.05). Expression of Kv4.2 was significantly reduced by 29%±12%, 24%±6%, and 41%±15%, respectively, in the MI group, CMS group, and model group, which could be improved by fluoxetine (30%±9%). But fluoxetine showed no improvement on the MI-induced loss of Cx43.</AbstractText>The susceptibility to ventricular arrhythmias was increased in depression and post-MI depression rats, and fluoxetine may reduce the incidence of ventricular arrhythmia in post-MI depression rats and thus improve the prognosis. This may be related in part to the upregulation of Kv4.2 by fluoxetine.</AbstractText> |
10,989 | Recurrence of atrial fibrillation after switching from brand to generic atenolol. | Beta blockers are the initial treatment for rate control of supraventricular tachyarrhythmia in patients without a history of myocardial infarction or left ventricular dysfunction. In this article we report the recurrence of atrial fibrillation after switching to the generic formulation of atenolol. |
10,990 | Serum uric acid and other short-term predictors of electrocardiographic alterations in the Brisighella Heart Study cohort. | Recent studies show that serum uric acid (SUA) is a predictor of atrial fibrillation, while its association with other kinds of arrhythmias is not yet established. We aimed to evaluate the incidence of the most common electrocardiographic alterations in a relatively large sample of general population and their association with SUA.</AbstractText>We selected a Brisighella Heart Study cohort sample of 1557 subjects, consecutively visited in the 2004 and 2008 surveys, in a setting of primary prevention for cardiovascular disease and without a known diagnosis of arrhythmia or left ventricular hypertrophy, excluding subjects affected by gout or taking any antihyperuricemic agent or drugs able to interfere with the QT interval. A step-wise Cox regression analysis was used to determine the independent prognostic significance of age, gender, physical activity, smoking, body mass index (BMI), fasting plasma glucose, mean arterial pressure (MAP), heart rate, LDL-cholesterol, HDL-cholesterol, triglycerides, SUA and eGFR on ECG alterations during a 4-year follow-up.</AbstractText>No one of the considered variables was associated with the incident diagnosis of sinus tachycardia and sinus bradycardia. SUA predicted incident tachyarrhythmias, Q waves and ECG signs of left ventricular hypertrophy; age, female sex and active smoking predicted incident tachyarrhythmias; male sex, active smoking and LDL-cholesterol predicted incident ECG signs of previous myocardial infarction; BMI and MAP predicted incident ECG-diagnosed left ventricular hypertrophy.</AbstractText>In a cohort of general population, SUA seems to be a significant middle-term predictor of electrocardiographically diagnosed myocardial infarction, left ventricular hypertrophy and tachyarrhythmias.</AbstractText>Copyright © 2015 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
10,991 | Interdisciplinary Approach in a Complex Case of STEMI. | We reported the case of a young man with ST-Segment Elevation Myocardial Infarction (STEMI), with ventricular fibrillation on debut and cardiogenic shock, who needed a complex interdisciplinary approach for a favourable long term outcome. A 43-year-old man was admitted with inferior STEMI and cardiogenic shock. First coronary angiography revealed total chronic occlusion of left anterior descending artery (LAD) and tight stenosis with thrombus on right coronary artery (RCA). Thrombus aspiration and stent implantation on RCA was performed with good results. LAD couldn't be opened. Intraaortic balloon pump was implanted. Forty-eight hours later, we try again to open LAD, without success. After a lot of complications, all solved with difficulty, patient was discharged cachectic and with progressive exertion on mild exercise. Two months later an implantable cardioverter-defibrillator (ICD) was decided for persistent ventricular tachycardia and after one year he was referred to a cardiac surgery centre abroad for aneurismectomy with left ventricle (LV) reconstruction and mitral valve repair. The patient is currently asymptomatic with a normal social and professional life. In conclusion, high performance cardiac surgery, after a complete interventional treatment, can improve quality of life and long-term outcome to a patient with severe cardiovascular disease. Team work between clinical cardiologists, interventional cardiologists, electrophisyologists, intensi-vists and cardiac surgeons is the key to success. |
10,992 | Echocardiographic Predictors of Progression to Persistent or Permanent Atrial Fibrillation in Patients with Paroxysmal Atrial Fibrillation (E6P Study). | Paroxysmal atrial fibrillation (AF) frequently, but not always, progresses to persistent/permanent AF. The aim of this study was to evaluate the echocardiographic predictors of AF progression in patients with paroxysmal AF.</AbstractText>A multicenter, prospective, observational study was conducted that included 313 patients with paroxysmal AF who underwent two-dimensional speckle-tracking echocardiography. The diameter, volume, and mechanical function of the left atrium, including global strain (ε) and ε rate, were measured.</AbstractText>Progression to persistent or permanent AF occurred in 52 patients (16.6%) during a median follow-up period of 26 months. Echocardiographic measure of left atrial (LA) diameter, volume, and function (E velocity, E/A and E/e' ratio, LA expansion index, active emptying fraction, global longitudinal ε and ε rate) were associated with AF progression. LA ε ≤ 30.9% was the strongest predictor of AF progression, which was associated with a more than fourfold hazard increase for AF progression (hazard ratio, 4.224; P = .001). LA diameter > 39 mm and maximal LA volume index > 34.2 mL/m(2) were associated with about a twofold hazard increase for AF progression (hazard ratios, 1.994 and 2.649; P = .016 and P = .001, respectively). When adjusted for a model combining maximal LA volume index, E velocity, LA expansion index, and active emptying fraction, LA ε ≤ 30.9% maintained a more than threefold hazard increase for AF progression (adjusted hazard ratio, 3.970; P = .003).</AbstractText>Echocardiographic measures of LA diameter, volume, and mechanical function, including LA ε, were associated with AF progression. LA ε was the strongest independent predictor of AF progression and is expected to serve as a valuable predictor of AF progression.</AbstractText>Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,993 | Assessing the early changes of cerebral glucose metabolism via dynamic (18)FDG-PET/CT during cardiac arrest. | To study the changes of cerebral glucose metabolism (CGM) during the phase of return of spontaneous circulation (ROSC) after cardiac arrest (CA), we used 18-fluorodeoxyglucose-positron emission tomography/computed tomography ((18)FDG-PET/CT) to measure the CGM changes in six beagle canine models. After the baseline (18)FDG-PET/CT was recorded, ventricular fibrillation (VF) was induced for 6 min, followed by close-chest cardiopulmonary resuscitation (CPR) in conjunction with intravenous (IV) administration of epinephrine and external defibrillator shocks until ROSC was achieved, within 30 min. The (18)FDG was recorded prior to intravenous administration at 0 h (baseline), and at 4, 24, and 48 h after CA with ROSC. We evaluated the expression of two key control factors in canine CGM, hexokinase I (HXK I) and HXK II, by immunohistochemistry at the four above mentioned time points. Electrically induced VF of 6 min duration was successfully induced in the dogs. Resuscitation was then performed to maintain blood pressure stability. Serial (18)FDG-PET/CT scans found that the CGM decreased at 4 h after ROSC and remained lower than the baseline even at 48 h. The expression of HXK I and II levels were consistent with the changes in CGM. These data from our present work showed that (18)FDG-PET/CT imaging can be used to detect decreased CGM during CA and was consistent with the results of CMRgl. Furthermore, there were also concomitant changes in the expression of HXK I and HXK II. The decrease in CGM may be an early sign of hyperacute global cerebral ischemia. |
10,994 | Effects of enhanced pacing modalities on health care resource utilization and costs in bradycardia patients: An analysis of the randomized MINERVA trial. | Many patients who suffer from bradycardia and need cardiac pacing also have atrial fibrillation (AF). New pacemaker algorithms, such as atrial preventive pacing and atrial antitachycardia pacing (DDDRP) and managed ventricular pacing (MVP), have been specifically designed to reduce AF occurrence and duration and to minimize the detrimental effects of right ventricular pacing. The randomized MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure trial established that DDDRP + MVP pacing modality reduced permanent AF in bradycardia patients as compared with standard dual-chamber pacing (DDDR).</AbstractText>The aim of this study was to estimate the cost savings due to lower AF-related health care utilization events based on health care costs from the United States and the European Union.</AbstractText>Dual-chamber pacemaker patients with a history of paroxysmal or persistent AF were randomly assigned to receive DDDR (n = 385) or the advanced features (DDDRP + MVP; n = 383). We used published health care costs from the United States and the European Union (Italy, Spain, and the United Kingdom) to estimate the costs associated with AF-related hospitalizations and emergency visits.</AbstractText>The rate of AF-related hospitalizations was significantly lower in the DDDRP + MVP group than in the conventional pacemaker group (DDDR group; 42% reduction; incidence rate ratio 0.58). Similarly, a significant reduction of 68% was observed for AF-related emergency department visits (incidence rate ratio 0.32; P < .001). As a consequence, DDDRP + MVP could potentially reduce health care costs by 40%-44%. Over a ten-year period, the cost savings per 100 patients ranged from $35,702 in the United Kingdom to $121,831 in the United States.</AbstractText>New pacing algorithms such as DDDRP + MVP used in the MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure trial successfully reduced AF-related health care utilization, resulting in significant cost savings to payers.</AbstractText>Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
10,995 | Atrial-like cardiomyocytes from human pluripotent stem cells are a robust preclinical model for assessing atrial-selective pharmacology. | Drugs targeting atrial-specific ion channels, Kv1.5 or Kir3.1/3.4, are being developed as new therapeutic strategies for atrial fibrillation. However, current preclinical studies carried out in non-cardiac cell lines or animal models may not accurately represent the physiology of a human cardiomyocyte (CM). In the current study, we tested whether human embryonic stem cell (hESC)-derived atrial CMs could predict atrial selectivity of pharmacological compounds. By modulating retinoic acid signaling during hESC differentiation, we generated atrial-like (hESC-atrial) and ventricular-like (hESC-ventricular) CMs. We found the expression of atrial-specific ion channel genes, KCNA5 (encoding Kv1.5) and KCNJ3 (encoding Kir 3.1), in hESC-atrial CMs and further demonstrated that these ion channel genes are regulated by COUP-TF transcription factors. Moreover, in response to multiple ion channel blocker, vernakalant, and Kv1.5 blocker, XEN-D0101, hESC-atrial but not hESC-ventricular CMs showed action potential (AP) prolongation due to a reduction in early repolarization. In hESC-atrial CMs, XEN-R0703, a novel Kir3.1/3.4 blocker restored the AP shortening caused by CCh. Neither CCh nor XEN-R0703 had an effect on hESC-ventricular CMs. In summary, we demonstrate that hESC-atrial CMs are a robust model for pre-clinical testing to assess atrial selectivity of novel antiarrhythmic drugs. |
10,996 | Myocardial electrotonic response to submaximal exercise in dogs with healed myocardial infarctions: evidence for β-adrenoceptor mediated enhanced coupling during exercise testing. | Autonomic neural activation during cardiac stress testing is an established risk-stratification tool in post-myocardial infarction (MI) patients. However, autonomic activation can also modulate myocardial electrotonic coupling, a known factor to contribute to the genesis of arrhythmias. The present study tested the hypothesis that exercise-induced autonomic neural activation modulates electrotonic coupling (as measured by myocardial electrical impedance, MEI) in post-MI animals shown to be susceptible or resistant to ventricular fibrillation (VF).</AbstractText>Dogs (n = 25) with healed MI instrumented for MEI measurements were trained to run on a treadmill and classified based on their susceptibility to VF (12 susceptible, 9 resistant). MEI and ECGs were recorded during 6-stage exercise tests (18 min/test; peak: 6.4 km/h @ 16%) performed under control conditions, and following complete β-adrenoceptor (β-AR) blockade (propranolol); MEI was also measured at rest during escalating β-AR stimulation (isoproterenol) or overdrive-pacing.</AbstractText>Exercise progressively increased heart rate (HR) and reduced heart rate variability (HRV). In parallel, MEI decreased gradually (enhanced electrotonic coupling) with exercise; at peak exercise, MEI was reduced by 5.3 ± 0.4% (or -23 ± 1.8Ω, P < 0.001). Notably, exercise-mediated electrotonic changes were linearly predicted by the degree of autonomic activation, as indicated by changes in either HR or in HRV (P < 0.001). Indeed, β-AR blockade attenuated the MEI response to exercise while direct β-AR stimulation (at rest) triggered MEI decreases comparable to those observed during exercise; ventricular pacing had no significant effects on MEI. Finally, animals prone to VF had a significantly larger MEI response to exercise.</AbstractText>These data suggest that β-AR activation during exercise can acutely enhance electrotonic coupling in the myocardium, particularly in dogs susceptible to ischemia-induced VF.</AbstractText> |
10,997 | Functional role of voltage gated Ca(2+) channels in heart automaticity. | Pacemaker activity of automatic cardiac myocytes controls the heartbeat in everyday life. Cardiac automaticity is under the control of several neurotransmitters and hormones and is constantly regulated by the autonomic nervous system to match the physiological needs of the organism. Several classes of ion channels and proteins involved in intracellular Ca(2+) dynamics contribute to pacemaker activity. The functional role of voltage-gated calcium channels (VGCCs) in heart automaticity and impulse conduction has been matter of debate for 30 years. However, growing evidence shows that VGCCs are important regulators of the pacemaker mechanisms and play also a major role in atrio-ventricular impulse conduction. Incidentally, studies performed in genetically modified mice lacking L-type Cav1.3 (Cav1.3(-/-)) or T-type Cav3.1 (Cav3.1(-/-)) channels show that genetic inactivation of these channels strongly impacts pacemaking. In cardiac pacemaker cells, VGCCs activate at negative voltages at the beginning of the diastolic depolarization and importantly contribute to this phase by supplying inward current. Loss-of-function of these channels also impairs atrio-ventricular conduction. Furthermore, inactivation of Cav1.3 channels promotes also atrial fibrillation and flutter in knockout mice suggesting that these channels can play a role in stabilizing atrial rhythm. Genomic analysis demonstrated that Cav1.3 and Cav3.1 channels are widely expressed in pacemaker tissue of mice, rabbits and humans. Importantly, human diseases of pacemaker activity such as congenital bradycardia and heart block have been attributed to loss-of-function of Cav1.3 and Cav3.1 channels. In this article, we will review the current knowledge on the role of VGCCs in the generation and regulation of heart rate and rhythm. We will discuss also how loss of Ca(2+) entry through VGCCs could influence intracellular Ca(2+) handling and promote atrial arrhythmias. |
10,998 | The effectiveness of prophylactic attachment of adhesive defibrillation pads in adult living donor liver transplantation. | The aim of current study is to present the effectiveness of prophylactic attachment of adhesive defibrillation electrode pads in adult living donor liver transplantation.</AbstractText>We divided 487 adult living donor liver transplantation patients into 2 Eras according to the history of without (Era 1) and with (Era 2) pre-attachment of adhesive defibrillation pads. The incidences of intraoperative cardiac events requiring cardioversion or defibrillation, its management, and outcome between Era 1 and 2 were compared.</AbstractText>Two cases out of 124 patients (1.6%) in Era 1 had cardiac arrest. The closed chest cardiac massage in 1 cardiac arrest in Era 1 required trans-diaphragmatic open-chest cardiac massage followed by internal cardiac defibrillation due to difficulty in performing external defibrillation. Both patients of Era 1 had in-hospital mortality. Four patients of Era 2 (n=363) received electrical treatment (1.01%); 2 had paroxysmal tachycardia requiring cardio-version and the other 2 had ventricular fibrillation requiring closed-chest cardiac massage and external defibrillation. All 4 patients in Era 2 regained sinus rhythm after electrical treatment, tolerated the subsequent operation well, and had 100% survival to date.</AbstractText>Our results show that prophylactic attachment of adhesive defibrillation pads allows the immediate performance of cardioversion, conventional closed-chest CPR, and defibrillation if indicated without any delay and without interference with the sterility of the operation field. Our preliminary result is clear and encouraging.</AbstractText> |
10,999 | [Catheter ablation of focus triggering ventricular fibrillation in patients with structural heart disease]. | First experiences with ablation of focus triggering ventricular fibrillation were reported in isolated cases of idiopathic ventricular fibrillation. Later, there were described the options in management of an electrical instability triggered by ectopic activity in patients after myocardial infarction. In both cases it was shown that the sources of extrasystoles originate almost exclusively from conducting system of chambers. Subsequently, isolated cases were also reported in other structural diseases. It is important that the urgent catheter ablation is able to remove focus which triggers electric instability. In many cases it is a lifesaving procedure. This review summarizes the current knowledge of the catheter ablation of focus triggering ventricular fibrillation with structural heart disease. |
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