Unnamed: 0 int64 0 2.34M | titles stringlengths 5 21.5M | abst stringlengths 1 21.5M |
|---|---|---|
13,300 | Increased amount of interstitial fibrosis predicts ventricular arrhythmias, and is associated with reduced myocardial septal function in patients with obstructive hypertrophic cardiomyopathy. | Reduced echocardiographic strain is associated with ventricular arrhythmias in hypertrophic cardiomyopathy (HCM) patients. The aim of this cross-sectional study was to investigate which type of histological fibrosis contributes to ventricular arrhythmias and reduced septal longitudinal strain, in obstructive HCM-patients with or without additional coronary artery disease (CAD) and/or hypertension (HT).</AbstractText>Sixty-three HCM-patients (mean age 57 ± 13 years) were included. Strain by speckle tracking echocardiography was performed prior to either percutaneous transluminal septal ablation (n = 37) or septal myectomy (n = 26). In 24 patients myectomy specimens were available (histology population) and allowed determination of %area of interstitial and replacement fibrosis. Twenty-nine (46%) patients had concomitant CAD and/or HT, and 15 (24%) experienced ventricular arrhythmias defined as documented ventricular tachycardia or arrhythmogenic suspected syncope. The patients with ventricular arrhythmias had lower septal longitudinal strain compared with those without arrhythmias (-9.0 ± 4.0 vs. -13.6 ± 5.6%, P = 0.006). In the histology population reduced septal longitudinal strain correlated to interstitial (R(2) = 0.36 P = 0.003), but not to replacement fibrosis (R(2) = 0.03 P = 0.43). By logistic regression analyses, interstitial fibrosis predicted ventricular arrhythmias (OR 1.16, 95% CI 1.02-1.32, P = 0.03), while replacement fibrosis did not (OR 1.22, 95% CI 0.93-1.59, P = 0.15).</AbstractText>Total amount of fibrosis was a marker of ventricular arrhythmias in obstructive HCM-patients. Interstitial fibrosis seemed to be more important compared with replacement fibrosis in arrhythmogenesis, and was related to reduced septal myocardial function. These findings suggest that interstitial fibrosis may play an important role as the arrhythmogenic substrate, and that strain echocardiography can help detection of patients at risk.</AbstractText> |
13,301 | Oxidative stress, fibrosis, and early afterdepolarization-mediated cardiac arrhythmias. | Animal and clinical studies have demonstrated that oxidative stress, a common pathophysiological factor in cardiac disease, reduces repolarization reserve by enhancing the L-type calcium current, the late Na, and the Na-Ca exchanger, promoting early afterdepolarizations (EADs) that can initiate ventricular tachycardia and ventricular fibrillation (VT/VF) in structurally remodeled hearts. Increased ventricular fibrosis plays a key facilitatory role in allowing oxidative-stress induced EADs to manifest as triggered activity and VT/VF, since normal non-fibrotic hearts are resistant to arrhythmias when challenged with similar or higher levels of oxidative stress. The findings imply that antifibrotic therapy, in addition to therapies designed to suppress EAD formation at the cellular level, may be synergistic in reducing the risk of sudden cardiac death. |
13,302 | Obesity, brain natriuretic peptide levels and mortality in patients hospitalized with heart failure and preserved left ventricular systolic function. | An inverse relationship between brain natriuretic peptide (BNP) levels and body mass index (BMI) has been described for patients with left ventricular (LV) systolic dysfunction. In this study, the association of BMI, BNP levels and mortality in patients hospitalized for heart failure with preserved LV systolic function (HFpLVF) was investigated.</AbstractText>One hundred fifty consecutive patients (98% men) who were hospitalized with HFpLVF and had BNP levels measured on admission were analyzed. Patients were divided into categories of BMI: normal (BMI < 25 kg/m), overweight (BMI 25-29.9 kg/m) and obese (BMI ≥ 30 kg/m). Relevant clinical and echocardiographic characteristics and all-cause mortality were obtained through chart review.</AbstractText>BNP levels were significantly lower in obese (median = 227 pg/mL) and overweight (median = 396 pg/mL) patients compared with those with normal BMI (median = 608 pg/mL, P = 0.003). Higher BMI predicted BNP levels of <100 pg/mL. Compared with patients with normal BMI, overweight and obese patients had a significantly lower risk of total mortality, even after adjusting for other clinical characteristics, including log-transformed BNP levels, atrial fibrillation, the use of beta-blockers at discharge, age, hemoglobin levels and the presence of pulmonary congestion on admission. Higher BNP levels also independently predicted mortality.</AbstractText>An inverse relationship between BMI and BNP levels exists in patients hospitalized with HFpLVF. Higher BMI is associated with lower mortality, whereas higher BNP levels predict higher mortality in male patients with HFpLVF. These findings should be confirmed in a larger multicenter setting.</AbstractText> |
13,303 | Shen-Fu injection reduces impaired myocardial β-adrenergic receptor signaling after cardiopulmonary resuscitation. | Post-resuscitation myocardial dysfunction has been implicated as a major cause of fatal outcome in patients who survive initially successful cardiopulmonary resuscitation (CPR). In our previous study, we found that impaired myocardial β-adrenergic receptor (AR) signaling is a key mechanism in post-resuscitation myocardial dysfunction and Shen-Fu injection (SFI) can attenuate post-resuscitation myocardial dysfunction. However, whether SFI can prevent impaired post-resuscitation myocardial β-AR signaling is not yet known. In this study, we investigated the effect of SFI on impaired myocardial β-AR signaling occurring post-resuscitation in a porcine model of cardiac arrest.</AbstractText>Ventricular fibrillation was induced electrically in anesthetized male landrace domestic pigs. After 4 minutes of untreated ventricular fibrillation, cardiopulmonary resuscitation was initiated. Sixteen successfully resuscitated pigs were randomized to receive a continuous infusion of either SFI (0.5 ml/min; n = 8) or saline (placebo; n = 8) for 6 hours, beginning 15 minutes after the return of spontaneous circulation (ROSC). Hemodynamic and echocardiographic data were recorded. β-AR signaling was assessed at 6 hours after the intervention by measuring myocardial adenylate cyclase activity, β-AR density and β-AR kinase expression.</AbstractText>Treatment with SFI produced better maximum rate of left ventricular pressure increase (dp/dt(max)) and maximum rate of left ventricular pressure decline (-dp/dt(max)), cardiac output, and ejection fraction after ROSC. SFI treatment was also associated with lower myocardial β-adrenergic receptor kinase expression, whereas basal and isoproterenol-stimulated adenylate cyclase activity and the total β-AR density were significantly increased in the SFI group when compared with the placebo group.</AbstractText>SFI attenuated post-resuscitation myocardial dysfunction by preventing impaired myocardial β-AR signaling after CPR.</AbstractText> |
13,304 | Hot shot induction and reperfusion with a specific blocker of the es-ENT1 nucleoside transporter before and after hypothermic cardioplegia abolishes myocardial stunning in acutely ischemic hearts despite metabolic derangement: hot shot drug delivery before hypothermic cardioplegia. | Simultaneous inhibition of the cardiac equilibrative-p-nitrobenzylthioinosine (NBMPR)-sensitive (es) type of the equilibrative nucleoside transport 1 (ENT1) nucleoside transporter, with NBMPR, and adenosine deaminase, with erythro-9-[2-hydroxy-3-nonyl]adenine (EHNA), prevents release of myocardial purines and attenuates myocardial stunning and fibrillation in canine models of warm ischemia and reperfusion. It is not known whether prolonged administration of hypothermic cardioplegia influences purine release and EHNA/NBMPR-mediated cardioprotection in acutely ischemic hearts.</AbstractText>Anesthetized dogs (n = 46), which underwent normothermic aortic crossclamping for 20 minutes on-pump, were divided to determine (1) purine release with induction of intermittent antegrade or continuous retrograde hypothermic cardioplegia and reperfusion, (2) the effects of postischemic treatment with 100 μM EHNA and 25 μM NBMPR on purine release and global functional recovery, and (3) whether a hot shot and reperfusion with EHNA/NBMPR inhibits purine release and attenuates ventricular dysfunction of ischemic hearts. Myocardial biopsies and coronary sinus effluents were obtained and analyzed using high-performance liquid chromatography.</AbstractText>Warm ischemia depleted myocardial adenosine triphosphate and elevated purines (ie, inosine > adenosine) as markers of ischemia. Induction of intermittent antegrade or continuous retrograde hypothermic (4°C) cardioplegia releases purines until the heart becomes cold (<20°C). During reperfusion, the levels of hypoxanthine and xanthine (free radical substrates) were >90% of purines in coronary sinus effluent. Reperfusion with EHNA/NBMPR abolished ventricular dysfunction in acutely ischemic hearts with and without a hot shot and hypothermic cardioplegic arrest.</AbstractText>Induction of hypothermic cardioplegia releases purines from ischemic hearts until they become cold, whereas reperfusion induces massive purine release and myocardial stunning. Inhibition of cardiac es-ENT1 nucleoside transporter abolishes postischemic reperfusion injury in warm and cold cardiac surgery.</AbstractText>Published by Mosby, Inc.</CopyrightInformation> |
13,305 | Adjunctive renal sympathetic denervation to modify hypertension as upstream therapy in the treatment of atrial fibrillation (H-FIB) study: clinical background and study design. | Hypertension is the most important risk factor directly attributable to the high prevalence of atrial fibrillation (AF), and is one of the few modifiable risk factors for AF. Activation and overactivity of the sympathetic nervous system (SNS) have been implicated in the pathogenesis of both essential hypertension and AF. Catheter-based renal sympathetic denervation (RSDN) appears to be an effective adjunctive treatment for refractory hypertension, and may be beneficial in other conditions characterized by SNS overactivity, such as left ventricular hypertrophy and atrial arrhythmias.</AbstractText>The H-FIB study is a multicenter prospective, double-blind, randomized (1:1) controlled trial. The primary efficacy endpoint is antiarrhythmic drug-free freedom from AF recurrence through 12 months.</AbstractText>Patients with a history of significant hypertension who are receiving treatment with at least one antihypertensive agent who are planned for a first time ablation for symptomatic paroxysmal or persistent AF will be randomized to either AF ablation alone (control group) or AF ablation + RSDN (study group).</AbstractText>H-FIB is a multicenter, randomized trial that will test the hypothesis that adjunctive renal sympathetic denervation, at the time of AF ablation, will increase the freedom from recurrent AF.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,306 | Functional characterization of atrial electrograms in a pacing-induced heart failure model of atrial fibrillation: importance of regional atrial connexin40 remodeling. | Heart failure (HF) increases the susceptibility to atrial fibrillation (AF) and is associated with altered cardiomyocyte connexin. The regional remodeling of connexin(s) may contribute to the spatiotemporal organization of AF. This study sought to investigate the regional differences in connexin(s) and fibrosis in specific atrial regions and correlate that with the electrogram properties.</AbstractText>Biatrial electroanatomic mapping during sinus rhythm (electrogram voltage and velocity) and AF (dominant frequency, DF) was performed in 6 ventricular pacing-induced HF dogs (at 252 beats/minute for 6 weeks) and 6 controls. Atrial tissues were sampled from 7 specific sites for analysis of the connexin and fibrosis. HF caused marked atrial dilatation, and increased the induced AF duration (P < 0.001). Remodeled connexins, including a lower expression and more lateralization of both connexin40 (Cx40) and Cx43 as well as increased regional dispersion of Cx40, in the presence of diffuse enhanced atrial fibrosis, characterized the atrial substrate of the HF dogs (P < 0.01). Regional analysis showed abnormal velocity and low electrogram voltage in the areas with downregulated Cx40 and Cx43 was enhanced in the presence of marked atrial fibrosis (>30% of area, P < 0.01). During AF, lower expression of the Cx40 was associated with higher DF in areas of less and more fibrosis, respectively (R = 0.67 and 0.58, P < 0.01).</AbstractText>An altered expression of connexins correlated with the electrogram properties in the existence of diffuse enhanced atrial fibrosis associated with HF. The regional remodeling of Cx40 is likely an important factor in the maintenance of AF in HF.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,307 | Apamin-sensitive potassium current modulates action potential duration restitution and arrhythmogenesis of failing rabbit ventricles. | Apamin-sensitive K currents (I(KAS)) are upregulated in heart failure. We hypothesize that apamin can flatten action potential duration restitution (APDR) curve and can reduce ventricular fibrillation duration in failing ventricles.</AbstractText>We simultaneously mapped membrane potential and intracellular Ca (Ca(i)) in 7 rabbit hearts with pacing-induced heart failure and in 7 normal hearts. A dynamic pacing protocol was used to determine APDR at baseline and after apamin (100 nmol/L) infusion. Apamin did not change APD(80) in normal ventricles, but prolonged APD(80) in failing ventricles at either long (≥300 ms) or short (≤170 ms) pacing cycle length, but not at intermediate pacing cycle length. The maximal slope of APDR curve was 2.03 (95% confidence interval, 1.73-2.32) in failing ventricles and 1.26 (95% confidence interval, 1.13-1.40) in normal ventricles at baseline (P=0.002). After apamin administration, the maximal slope of APDR in failing ventricles decreased to 1.43 (95% confidence interval, 1.01-1.84; P=0.018), whereas no significant changes were observed in normal ventricles. During ventricular fibrillation in failing ventricles, the number of phase singularities (baseline versus apamin, 4.0 versus 2.5), dominant frequency (13.0 versus 10.0 Hz), and ventricular fibrillation duration (160 versus 80 s) were all significantly (P<0.05) decreased by apamin.</AbstractText>Apamin prolongs APD at long and short, but not at intermediate pacing cycle length in failing ventricles. I(KAS) upregulation may be antiarrhythmic by preserving the repolarization reserve at slow heart rate, but is proarrhythmic by steepening the slope of APDR curve, which promotes the generation and maintenance of ventricular fibrillation.</AbstractText> |
13,308 | Patient perceptions, physician communication, and the implantable cardioverter-defibrillator. | Implantable cardioverter-defibrillators (ICDs) have changed the way in which patients with chronic ventricular dysfunction are evaluated and treated.</AbstractText>To examine patient-physician communication at the time the decision is made to implant an ICD.</AbstractText><AbstractText Label="DESIGN, SETTING, AND PARTICIPANTS" NlmCategory="METHODS">Forty-one patients with ICDs and 11 cardiologists were recruited by a national marketing research company for a study comprising patient focus groups and standardized patient interviews in 3 different metropolitan areas.</AbstractText>Eight patient focus groups and (separately) 22 standardized patient interviews with cardiologists.</AbstractText>Patient focus group findings and the results of standardized patient interviews (each cardiologist interviewed 2 patients).</AbstractText>The mean (SD) patient age was 61.4 (14.7) years; 21 were female. Thirty-three patients could not recall a discussion about periprocedural or long-term complications. On a scale of 1 to 10, the mean (SD) rating of the degree to which patients felt informed before the implant procedure was 5.7 (3.2) (1 indicates "not at all informed," and 10 indicates "I had all the information I needed or wanted"). The mean (SD) estimated number of patients out of 100 who would be saved by the ICD was 87.9 (20.1). A negative perception on body image and lifestyle was prevalent. Across 22 standardized patient interviews, cardiologists frequently (in >17 of 22 of interviews) did not address or minimized or denied quality-of-life issues and long-term consequences of ICD placement, including the risk for depression, anxiety, and inappropriate delivery of shock or device advisory. In 15 of 22 of the standardized patient interviews, cardiologists used unexplained medical terms or jargon.</AbstractText>Patient-physician communication about ICDs is characterized by unclear representation and omission of information to patients, with notable lack of attention to psychological and long-term risks. Training of cardiologists on information exchange with patients may promote informed decision making and preempt threats to patient quality of life.</AbstractText> |
13,309 | Cycle length characteristics differentiating non-sustained from self-terminating ventricular fibrillation in Brugada syndrome. | Limited information is available on self-terminating (ST) ventricular fibrillation (VF). Understanding spontaneous fluctuations in VF cycle length (CL) is required to identify arrhythmia that will stop before shock. Using Brugada syndrome (BS) as a model, the purpose of the study was to compare ST-VF and VF terminated by electrical shock and to look for spontaneous fluctuations in ventricular CL.</AbstractText>Occurrence of ST-VF and VF was studied in 53 patients with 46 VF episodes: (i) spontaneously, (ii) during defibrillation threshold testing, (iii) during programmed ventricular stimulation (PVS). Fifteen presented ST-VF (average duration 25 s): 11 during PVS, 1 during defibrillation threshold testing, and 3 spontaneously (at device interrogation). Self-terminating ventricular fibrillation was compared with 31 VFs terminated by electrical shock. Mean ventricular CL was longer (192.5 ± 22 vs. 149 ± 19 ms) (P < 0.0001) and CL became longer or did not change in ST-VF (187 ± 28 vs. 200 ± 25 ms) (first vs. last CL)(NS) in contrast with progressively shorter CL in electrical shock-terminated VF (177 ± 14.5 vs. 139 ± 12 ms) (first vs. last CL before electrical shock) (P < 0.0001). Ventricular fibrillation had more CL variability (average 16.4 ± 6.5 ms) for the first 50 beats than ST-VF (average 4.08 ± 2) (P < 0.0001). Cycle length range for the first 50 beats was 9.6 ± 1 ms for ST-VF and 44 ± 15 for VF (P < 0.002).</AbstractText>Self-terminating ventricular fibrillation in BS was not rare (28%). Ventricular CL was longer and progressively increased or did not change in ST-VF compared with electrical shock-terminating VF. Cycle length variability and CL range could differentiate VF and ST-VF within the first 50 beats. These parameters should be considered in the algorithms for VF detection and termination.</AbstractText> |
13,310 | First responder for in-hospital resuscitation: 5-year experience with an automated external defibrillator-based program. | The survival of in-hospital cardiac arrest (8-25%) has not changed substantially in the past. Until now, most hospitals in Germany had no standardized protocols available for a course of action in case of emergency, and there are no continuous registry data for in-hospital cardiac arrest and survival.</AbstractText>Our aim was to improve survival and receive outcomes data, so we implemented a structured hospital-wide automated first-responder system in the hospital. Here our 5-year experience with 443 emergency calls is outlined.</AbstractText>Throughout the hospital, 15 automated external defibrillator (AED) "access spots," which can be easily reached within 30 s, were identified. AEDs were then installed at these locations (Lifepak 500 and Lifepak 1000, Medtronic equipped with a Biolog 3000i portable ECG monitor). At the same time, a training program was initiated in which the employees of the hospital participated once a year. Participants learned how to apply and activate an AED in case of cardiac arrest even before the designated Cardiac Arrest Team arrived at the scene.</AbstractText>A witnessed cardiac arrest event was confirmed in 126 cases. In 56 of the 126 cases, the primary arrest rhythm was either ventricular tachycardia or ventricular fibrillation and the AED delivered a shock. In this group, spontaneous circulation was reached in 44 cases (79%) and 23 patients (41%) were discharged. In 44% (24 from 55 patients) of the cases, a shock was recommended by AED and delivered by the first responders before the rescue team arrived.</AbstractText>The first-responder AED program successfully gave training lessons to the hospital staff. The training included how to initiate the cardiac arrest call, how to use the AED, and how to start immediate resuscitation. As a result, a higher survival rate after in-hospital cardiac arrest can be accomplished.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,311 | Usefulness of scintigraphy to predict electrical storms in severe idiopathic dilated cardiomyopathy. | Although several predictors of an electrical storm (ES) are indicated in patients with idiopathic dilated cardiomyopathy (IDCM), whether the severity of the myocardial tissue damage (SMTD) evaluated by myocardial perfusion SPECT (MPS) has an association with an ES remains unclear. The purpose of this study was to elucidate the clinical significance of SMTD for the prediction of ES in IDCM patients with an ICD.</AbstractText>Thirty-seven (27 men, mean age 58 ± 15 years) IDCM patients receiving ICD implantations for secondary prevention with preoperative MPS were enrolled in this study. The medical history, physical and laboratory findings, electrocardiograms, echocardiograms and MPS findings were evaluated. The SMTD was assessed by the summed scores of 17 segments using a 4-point system (0, normal ~3, severe defect).</AbstractText>During a mean follow-up of 43.9 ± 30.7 months, an ES developed in 12/37 (32.4 %) patients. The SMTD score predicted an ES with a 92 % sensitivity and 56 % specificity, at a cut-off score of 10. In addition, a multivariate analysis showed that the SMTD score remained an independent predictor of an ES (HR 1.09/score 1 increase, 95 % CI 1.01-1.19, p = 0.02). The SMTD score was significantly associated with three indices of late potentials on the signal-averaged electrocardiograms, and was significantly higher in patients with positive late potentials (p = 0.0006).</AbstractText>SMTD score assessed by MPS has a strong correlation to the late potentials and higher SMTD score may increase the risk of ES among patients with IDCM and an ICD.</AbstractText> |
13,312 | Left atrial size and function as predictors of new-onset of atrial fibrillation in patients with asymptomatic aortic stenosis: the simvastatin and ezetimibe in aortic stenosis study. | Left atrial (LA) size and function change with chronically increased left ventricular (LV) filling pressures. It remains unclear whether these variations in LA parameters can predict new-onset atrial fibrillation (AF) in asymptomatic patients with aortic stenosis (AS).</AbstractText>Data were obtained in asymptomatic patients with mild-to-moderate AS (2.5 ≤ transaortic Doppler velocity ≤ 4.0m/s), preserved LV ejection fraction (EF), no previous AF, and were enrolled in the Simvastatin and Ezetimibe in Aortic Stenosis study. Peak-aortic velocity, LA(max) volume & LAmin volume were measured by echocardiography. LA conduit (LA(con)) volume was defined as LV stroke volume-LA stroke volume. LA function was expressed as LA-EF (LA(max)-LAmin volume/LA(max)).</AbstractText>In the 1159 patients included, new-onset AF occurred in 71 patients (6.1%) within a mean follow-up of 4.2 ± 0.9 years. Mean age was 66 ± 9.7 years, aortic valve area index 0.6 ± 0.2 cm(2)/m(2), LV mass 99.2 ± 29.7 g/m(2), LA(max) volume 34.6 ± 12.0 mL/m(2), LAmin volume 17.9 ± 9.3 mL/m(2), LA-EF 50 ± 15% and LA(con) volume 45 ± 21 mL/m(2). Baseline LAmin volume predicted new-onset AF in Cox multivariable analysis (HR:2.3 [95%CI:1.3-4.4], P<0.01), and added prognostic information on AF development beyond conventional risk factors (likelihood ratio, P<0.01). In comparison of c-indexes LAmin volume was superior to all other LA measurements. Net reclassification index improved by 15.9% when adding LAmin volume to a model with classic risk factors for AF (P=0.01).</AbstractText>LAmin volume independently predicted new-onset AF in patients with asymptomatic AS and was superior to LA-EF, LA(con) and LA(max) volumes and conventional risk factors.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,313 | Sleep disordered breathing as a risk of cardiac events in subjects with diabetes mellitus and normal exercise echocardiographic findings. | Sleep disordered breathing (SDB) is associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease; however, the contribution of SDB to incident heart failure (HF), coronary artery disease (CAD), and atrial fibrillation (AF) in patients with T2DM is unknown. We followed up 834 consecutive asymptomatic patients with T2DM (age 56 ± 11 years, 369 women) with normal exercise echocardiographic findings for ≤8 years using electronic health records. The demographics, cardiac risk factors, symptoms, diagnoses, and medications were collected at the echocardiography and validated from the electronic health records. SDB was confirmed by a comprehensive sleep evaluation and/or polysomnography before echocardiography. SDB was diagnosed in 188 patients (21%) at baseline; 116 were untreated. During a median follow-up of 4.9 years (interquartile range 3.9 to 6.1), 22 congestive HF, 72 CAD, and 40 AF incident events were observed. In the Cox proportional hazards models, SDB was associated with incident CAD (hazard ratio 1.8, 95% confidence interval 1.1 to 3.0, p = 0.01; adjusted hazard ratio 1.9, 95% confidence interval 1.2 to 3.2, p <0.01) and AF (hazard ratio 2.6, 95% confidence interval 1.4 to 4.7, p = 0.01; adjusted hazard ratio 2.9, 95% confidence interval 1.5 to 5.9, p <0.01). Limiting SDB to only those patients diagnosed using polysomnography (n = 132), SDB was associated with incident CAD (hazard ratio 1.9, 95% confidence interval 1.1 to 3.3, p = 0.03; adjusted hazard ratio 2.2, 95% confidence interval 1.2 to 3.9, p = 0.01) and HF (hazard ratio 2.7, 95% confidence interval 1.1 to 7.0, p = 0.03; adjusted hazard ratio 3.5, 95% confidence interval 1.4 to 9.0, p <0.01). Female gender, age, elevated blood pressure, and left ventricular mass were additional correlates of CAD in those with asymptomatic T2DM. In conclusion, the association of SDB with incident CAD, AF, and HF in patients with T2DM justifies more liberal screening for SDB in patients with T2DM, realizing that SDB is a potentially modifiable risk factor. |
13,314 | Effects of irbesartan on gene expression revealed by transcriptome analysis of left atrial tissue in a porcine model of acute rapid pacing in vivo. | Atrial fibrillation (AF) is characterized by electrical and structural remodeling of the atria with atrial fibrosis being one hallmark. Angiotensin II (AngII) is a major contributing factor and blockage of its type I receptor (AT1R) prevents remodeling to some extent. Here we explored the effects of the AT1R antagonist irbesartan on global gene expression and profibrotic signaling pathways after induction of rapid atrial pacing (RAP) in vivo in pigs.</AbstractText>Microarray-based RNA profiling was used to screen left atrial (LA) tissue specimens for differences in atrial gene expression in a model of acute RAP. RAP caused an overall expression profile that reflected AngII-induced ROS production, tissue remodeling, and energy depletion. Of special note, the mRNA levels of EDN1, SGK1, and CTGF encoding pro-endothelin, stress- and glucocorticoid activated kinase-1, and of connective tissue growth factor were identified to be significantly increased after 7h of rapid pacing. These specific expression changes were additionally validated by RT-qPCR or immunoblot analyses in LA, RA, and partly in LV samples. All RAP-induced differential gene expression patterns were partially attenuated in the presence of irbesartan. Similar results were obtained after RAP of HL-1 cardiomyocytes in vitro. Furthermore, exogenously added endothelin-1 (ET1) induced CTGF expression concomitant to the transcriptional activation of SGK1 in HL-1 cells.</AbstractText>RAP provokes substantial changes in atrial and ventricular myocardial gene expression that could be partly reversed by irbesartan. ET1 contributes to AF-dependent atrial fibrosis by synergistic activity with AngII to stimulate SGK1 expression and enhance phosphorylation of the SGK1 protein which, in turn, induces CTGF. The latter has been consistently associated with tissue fibrosis. These findings suggest ETR antagonists as being beneficial in AF treatment.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,315 | Chloroquine cardiotoxicity mimicking connective tissue disease heart involvement. | The authors report a case of rare chloroquine cardiotoxicity mimicking connective tissue disease heart involvement in a 56-year-old woman with mixed connective tissue disease (MCTD) manifested suddenly as third degree A-V block with QT(c) interval prolongation and short torsade de pointes runs ultimately degenerating into ventricular fibrillation. Immunological tests suggested an MCTD flare, implying that cardiac arrest had resulted from myocardial involvement by MCTD. However, QT(c) prolongation is not a characteristic of cardiomyopathy caused by connective tissue disease, unless anti-Ro/SSA positivity is present, but that was not the case. Therefore, looking for another cause of QT(c) prolongation the possibility of chloroquine cardiotoxicity emerged, which the patient had been receiving for almost two years in supramaximal doses. Biopsy of the deltoid muscle was performed, because in chloroquine toxicity, specific lesions are present both in the skeletal muscle and in the myocardium, and electron microscopy revealed the accumulation of cytoplasmic curvilinear bodies, which are specific to antimalarial-induced myocyte damage and are absent in all other muscle diseases, except neuronal ceroid lipofuscinosis. Thus, the diagnosis of chloroquine cardiotoxicity was established. It might be advisable to supplement the periodic ophthalmological examination, which is currently the only recommendation for patients on long-term chloroquine therapy, with ECG screening. |
13,316 | Hybrid Melody pulmonary valve replacement in an adult with severe pulmonary hypertension and pulmonary artery aneurysm. | A 48-year-old female with D-TGA, ventricular septal defect (VSD), pulmonary stenosis, pulmonary hypertension (PAH), and total anomalous pulmonary venous connection underwent hybrid intervention for a pulmonary artery (PA) aneurysm and replacement of a dysfunctional pulmonary valve (PV). She underwent a hemi-Mustard procedure at 9 years of age but remained cyanotic. She developed atrial fibrillation, heart failure, and functional decline at 43 years of age. A chest CT demonstrated a 6 cm PA aneurysm that upon re-imaging at 48 years had increased to 11 cm. A catheterization procedure revealed severe PS, PR, residual VSD, severe PAH with a pulmonary vascular resistance of 30 Wood units. She was evaluated and turned down for heart-lung transplantation at another institution. She was subsequently referred to our institution for heart-lung transplantation but was felt to be at unacceptably high risk given the complexity of her anatomy, imaging suggesting liver cirrhosis and liver biopsy with extensive fibrosis. After extensive discussion of risk and benefits, the patient agreed to proceed with a hybrid intervention, consisting of surgical aneurysm resection/PA repair, tricuspid valve repair; PV replacement with a Melody valve, and VSD closure. There were no complications and she was discharged home within 2 weeks. Six months post procedure, she is not on oxygen, her resting room air saturation is 94%, and echocardiography shows stable Melody valve function. This case highlights the utility of a hybrid approach in the treatment of an adult with complex congenital heart disease, heart failure and severe PAH, considered at the highest risk for adverse surgical outcomes. The short-term efficacy of the Melody valve in severe PAH is reassuring. |
13,317 | Atrial fibrillation and the risk of sudden cardiac death: the atherosclerosis risk in communities study and cardiovascular health study. | It is unknown whether atrial fibrillation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. This association was examined in 2 population-based cohorts.</AbstractText>In the Atherosclerosis Risk in Communities (ARIC) Study, we analyzed data from 15 439 participants (baseline age, 45-64 years; 55.2% women; and 26.6% black) from baseline (1987-1989) through December 31, 2001. In the Cardiovascular Health Study (CHS), we analyzed data from 5479 participants (baseline age, ≥65 years; 58.2% women; and 15.4% black) from baseline (first cohort, 1989-1990; second cohort, 1992-1993) through December 31, 2006. The main outcome was physician-adjudicated SCD, defined as death from a sudden, pulseless condition presumed to be due to a ventricular tachyarrhythmia. The secondary outcome was non-SCD (NSCD), defined as coronary heart disease death not meeting SCD criteria. We used Cox proportional hazards models to assess the association between AF and SCD/NSCD, adjusting for baseline demographic and cardiovascular risk factors.</AbstractText>In the ARIC Study, 894 AF, 269 SCD, and 233 NSCD events occurred during follow-up (median, 13.1 years). The crude incidence rates of SCD were 2.89 per 1000 person-years (with AF) and 1.30 per 1000 person-years (without AF). The multivariable hazard ratios (HRs) (95% CIs) of AF for SCD and NSCD were 3.26 (2.17-4.91) and 2.43 (1.60-3.71), respectively. In the CHS, 1458 AF, 292 SCD, and 581 NSCD events occurred during follow-up (median, 13.1 years). The crude incidence rates of SCD were 12.00 per 1000 person-years (with AF) and 3.82 per 1000 person-years (without AF). The multivariable HRs (95% CIs) of AF for SCD and NSCD were 2.14 (1.60-2.87) and 3.10 (2.58-3.72), respectively. The meta-analyzed HRs (95% CIs) of AF for SCD and NSCD were 2.47 (1.95-3.13) and 2.98 (2.52-3.53), respectively.</AbstractText>Incident AF is associated with an increased risk of SCD and NSCD in the general population. Additional research to identify predictors of SCD in patients with AF is warranted.</AbstractText> |
13,318 | Relationship of sudden cardiac death to new-onset atrial fibrillation in hypertensive patients with left ventricular hypertrophy. | Prevalent atrial fibrillation (AF) is associated with a higher sudden cardiac death (SCD) rate in some populations, and incident AF predicts increased mortality risk in the general population and after myocardial infarction. However, the relationship of SCD to new-onset AF is unclear.</AbstractText>The relationship of SCD to new-onset AF was evaluated in 8831 hypertensive patients with electrocardiographic left ventricular hypertrophy with no history of AF, in sinus rhythm on their baseline electrocardiogram, randomly assigned to losartan- or atenolol-based treatment. During 4.7±1.1 years mean follow-up, new-onset AF occurred in 701 patients (7.9%) and SCD in 151 patients (1.7%). In univariate Cox analyses, new-onset AF was associated with a >4-fold higher risk of SCD (hazard ratio, 4.69; 95% CI interval, 2.96-7.45; P<0.001). In multivariate Cox analyses adjusting for age, sex, race, diabetes mellitus, history of heart failure, myocardial infarction, ischemic heart disease, stroke, smoking, serum high-density lipoprotein cholesterol, creatinine, glucose, and urine albumin/creatinine ratio as standard risk factors, and for incident myocardial infarction, in-treatment use of digoxin, systolic and diastolic pressure, heart rate, QRS duration, Cornell voltage-duration product, and Sokolow-Lyon voltage left ventricular hypertrophy treated as time-varying covariates, new-onset AF remained associated with a >3-fold increased risk of SCD (hazard ratio, 3.13; 95% confidence interval, 1.87-5.24; P<0.001).</AbstractText>Development of new-onset AF identifies hypertensive patients at increased risk of SCD.</AbstractText>URL: http://www.clinicaltrials.gov. Unique identifier: NCT00338260.</AbstractText> |
13,319 | Selective heart rate reduction with ivabradine slows ischaemia-induced electrophysiological changes and reduces ischaemia-reperfusion-induced ventricular arrhythmias. | Heart rates during ischaemia and reperfusion are possible determinants of reperfusion arrhythmias. We used ivabradine, a selective If current inhibitor, to assess the effects of heart rate reduction (HRR) during ischaemia-reperfusion on reperfusion ventricular arrhythmias and assessed potential anti-arrhythmic mechanisms by optical mapping. Five groups of rat hearts were subjected to regional ischaemia by left anterior descending artery occlusion for 8min followed by 10min of reperfusion: (1) Control n=10; (2) 1μM of ivabradine perfusion n=10; (3) 1μM of ivabradine+5Hz atrial pacing throughout ischaemia-reperfusion n=5; (4) 1μM of ivabradine+5Hz pacing only at reperfusion; (5) 100μM of ivabradine was used as a 1ml bolus upon reperfusion. For optical mapping, 10 hearts (ivabradine n=5; 5Hz pacing n=5) were subjected to global ischaemia whilst transmembrane voltage transients were recorded. Epicardial activation was mapped, and the rate of development of ischaemia-induced electrophysiological changes was assessed. HRR observed in the ivabradine group during both ischaemia (195±11bpm vs. control 272±14bpm, p<0.05) and at reperfusion (168±13bpm vs. 276±14bpm, p<0.05) was associated with reduced reperfusion ventricular fibrillation (VF) incidence (20% vs. 90%, p<0.05). Pacing throughout ischaemia-reperfusion abolished the protective effects of ivabradine (100% VF), whereas pacing at reperfusion only partially attenuated this effect (40% VF). Ivabradine, given as a bolus at reperfusion, did not significantly affect VF incidence (80% VF). Optical mapping experiments showed a delay to ischaemia-induced conduction slowing (time to 50% conduction slowing: 10.2±1.3min vs. 5.1±0.7min, p<0.05) and to loss of electrical excitability in ivabradine-perfused hearts (27.7±4.3min vs. 14.5±0.6min, p<0.05). Ivabradine administered throughout ischaemia and reperfusion reduced reperfusion VF incidence through HRR. Heart rate during ischaemia is a major determinant of reperfusion arrhythmias. Heart rate at reperfusion alone was not a determinant of reperfusion VF, as neither a bolus of ivabradine nor pacing immediately prior to reperfusion significantly altered reperfusion VF incidence. This anti-arrhythmic effect of heart rate reduction during ischaemia may reflect slower development of ischaemia-induced electrophysiological changes. |
13,320 | Perioperative management difficulties in parathyroidectomy for primary versus secondary and tertiary hyperparathyroidism. | In patients with hyperparathyroidism, parathyroidectomy is the only curative therapy. Anaesthetic management differs function of etiology (primary vs. secondary or tertiary hyperparathyroidism) and surgical technique (minimally invasive or classic parathyroidectomy).</AbstractText>To evaluate peri-operative management (focusing on hemodynamic changes, cardiac arrhythmias and patients' awakening quality) in parathyroidectomy for hyperparathyroidism of various etiologies, in a tertiary center.</AbstractText>292 patients who underwent surgery for hyperparathyroidism between 2000-2011 were retrospectively reviewed; 96 patients (19M/77F) presented with primary hyperparathyroidism (group A) and 196 (80M/116F) with secondary and tertiary hyperparathyroidism due to renal failure (group B). Biochemical parameters (serum calcium, phosphate, creatinine) were determined by automated standard laboratory methods. Serum intact PTH was measured by ELISA (iPTH - normal range: 15-65 pg/mL).</AbstractText>Median surgery duration was 30 minutes in group A (minimally invasive or classic parathyroidectomy) and 75 minutes in group B (total parathyroidectomy and re implantation of a small parathyroid fragment into the sternocleidomastoid muscle). During anaesthesia induction, arterial hypotension developed significantly more frequent in group B (57 out of 196 pts, 29.1%) than in group A (8 out of 96 pts, 8.34%), p<0.0001, especially in patients receiving Fentanyl-Propofol. During surgery and anaesthesia maintenance, bradycardia was significantly more frequent in group A (67 out of 96 pts, 69.8%) than in group B (26 out of 196 pts, 13.3%), p<0.0001, especially during searching of parathyroid glands. By contrary, ventricular premature beats were less frequent in group A (25 out of 96 pts, 25.25%) than in group B (84 out of 196 pts, 42.85%), p=0.003. There were no statistically significant differences between the studied group regarding frequency of arterial hypertension and hypotension, paroxysmal atrial fibrillation.</AbstractText>anaesthetic management in parathyroid surgery may be difficult because of cardiac arrhythmias (bradycardia in primary hyperparathyroidism and ventricular premature beats in secondary and tertiary hyperparathyroidism, respectively) and arterial hypotension during anaesthesia induction in patients with secondary and tertiary hyperparathyroidism.</AbstractText> |
13,321 | Extreme but not life-threatening QT interval prolongation? Take a closer look at the neck! | We present the case of a 82-year-old woman with a history of total thyroidectomy who was admitted in hospital with severe hypocalcemia. A 12-lead surface ECG revealed atrial fibrillation along with an extremely prolonged QT interval of approximately 730ms. In the absence of any other possible cause of QT interval prolongation, hypocalcemia was attributed to surgical hypoparathyroidism and undue discontinuation of calcium supplementation. Surprisingly, no ventricular arrhythmias were recorded and calcium repletion was followed by normalization of QT interval. |
13,322 | A new antiarrhythmic drug in the treatment of recent-onset atrial fibrillation: vernakalant. | Vernakalant is a new antiarrhythmic agent recently approved in Europe for the rapid cardioversion of recent-onset atrial fibrillation. It works by blocking early-activating K+ atrial channels and frequency-dependent atrial Na+ channels, prolonging atrial refractory periods and rate-dependent slowing atrial conduction, without promoting ventricular arrhythmia. Preclinical and clinical trials showed good toleration of this drug. The main purpose of our review is to describe all the trials that led to the incorporation of vernakalant into the current European atrial fibrillation guidelines. |
13,323 | Early repolarization pattern associated with sudden cardiac death: long-term follow-up in patients with chronic heart failure. | Identification of patients with chronic heart failure (CHF) at a risk for sudden cardiac death (SCD) is an important objective. Early repolarization pattern (ERP) is associated with ventricular fibrillation in patients without structural heart diseases. Moreover, ERP was reported to be associated with SCD in patients with old myocardial infarction in a case-control study. However, little information is available on the prognostic significance of ERP in CHF patients. Thus, we aimed to investigate whether ERP is associated with SCD in CHF patients.</AbstractText>The study population consisted of 132 consecutive outpatients with NYHA class I, II and III congestive heart failure and radionuclide left ventricular ejection fraction less than 40%. All patients underwent the standard 12-lead electrocardiogram at enrollment, where we assessed the presence of ERP using the criteria of J-point elevation ≥ 0.1 mV in at least 2 inferior or lateral leads. The primary endpoint of this study was SCD. At enrollment, 16 patients had ERP. During the follow-up period of 6.7 ± 3.5 years, 26 patients had SCD. Kaplan-Meier analysis showed that SCD was observed significantly more frequently in patients with ERP than in those without ERP (63% [10/16] vs 14% [16/116], P < 0.0001]. A multivariate Cox analysis revealed that ERP was significantly and independently associated with SCD (hazard ratio, 3.7; 95% confidence interval, 1.6-8.6; P = 0.002).</AbstractText>ERP in inferior leads would be associated with an increased risk of SCD in CHF patients.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,324 | Atrial Fibrillation in Patients with Cardiac Resynchronization Therapy: Clinical Management and Outcome. | Atrial fibrillation (AF) and heart failure (HF) are two emerging epidemics in the cardiovascular field and are strictly inter-related since may directly predispose to each other. Cardiac resynchronization therapy (CRT) has emerged as an important therapeutic option for selected HF patients with LV dysfunction and ventricular dyssynchrony. However almost all RCTs demonstrated the CRT effectiveness in patients in sinus rhythm (SR), including permanent AF among the exclusion criteria. In patients with paroxysmal or persistent AF strategies for rhythm control can be applied, but usually with limited efficacy. Furthermore, rhythm control strategy did not result superior to rate-control in patients with heart failure. AF ablation in HF patients is usually performed only in selected centres. In patients with permanent or long-standing AF and a CRT device the option of AVN ablation offers the advantage of allowing >95% biventricular pacing. AF implies a harmful increase in thromboembolic risk. Detection of AF in patients treated with a CRT device is enhanced by device diagnostic capabilities, that allow detection of episodes of atrial tachyarrythmias, including silent AF. In these cases decision making on appropriate antithrombotic prophy/laxis has to consider clinical risk stratification, usually applying CHADS<sub>2</sub> and CHA<sub>2</sub>DS<sub>2</sub>VASc scores. In summary, in order to maximise outcome, AF in patients with CRT prompts the need to appropriately decide on antithromboembolic prophylaxis (according to risk stratifications), as well as on rate and/or rhythm control strategies, with the aim to allow constant biventricular pacing. In this perspective, AVN ablation has an important role since by inducing pace-maker dependency guarantees continuous biventricular pacing. |
13,325 | Prophylactic Antiarrhythmic Drug Therapy in Atrial Fibrillation. | In patients with recurrent atrial fibrillation (AF), the hallmark of treatment has been the use of antiarrhythmic drugs (AADs). Goals of therapy include reduction in the frequency and duration of episodes of arrhythmia as well an emerging goal of reducing mortality and hospitalizations associated with AF. Safety and efficacy are important factors when choosing an antiarrhythmic drug for the treatment of AF, hence, if AAD are required for maintenance of sinus rhythm, their safety profi le, together with individual patient characteristics, should be of utmost concern. In the next paragraphs we would like to review some aspects (electrophysiologic effects, metabolism, side effects, current evidence and indication) of the most commonly used AAD for the management of patients with AF, following the Vaughan-Williams classification. However, this system is mainly based on ventricular activity, therefore, and due to its relatively atrial selective actions, some agents will not readily fit in the Vaughan Williams AAD classification. For that reason, in the final part of the manuscript, new promising agents will be reviewed separately. |
13,326 | Atrial Fibrillation in Patients with Ischemic and Non-Ischemic Left Ventricular Dysfunction. | Atrial fibrillation (AF) and left ventricular dysfunction (LVD) are increasingly common clinical problems, affecting millions of people worldwide. It is well established that the presence of AF portends a poor prognosis in the setting of both ischemic and non-ischemic LVD, and frequently results in worsening clinical status. Many clinical studies and trials have attempted to address treatment options and efficacy; despite this treatment for AF in LVD is still controversial. |
13,327 | Amiodarone Induced Thyrotoxicosis - Fluctuating RVOT and LV Scar VT. | A 61 year old patient with non-ischemic cardiomyopathy and implantable cardioverter defibrillator presented with multiple shocks for ventricular tachycardia (VT). EKG revealed monomorphic sustained VT which was left bundle inferior axis that spontaneously changed into sustained VT which was right bundle superior axis. This was suggestive of an outflow tract VT transforming into a VT probably related to reentry from LV scar. The patient was transferred to our university for VT ablation. However, further investigation revealed amiodarone induced hyperthyroidism which was the cause of his ventricular tachycardia storm. Reversible causes of VT should be considered before proceeding with radiofrequency ablation. |
13,328 | Survival of a highly toxic dose of caffeine. | A 27-year-old woman with a history of depression and previous overdose presented within 60 min of ingestion of 50 g of caffeine powder. Initially alert but hypotensive and tachycardic, the patient developed a broad complex tachycardia followed by a seizure and multiple ventricular fibrillation (VF) arrests. Following multiple defibrillations for VF, eight cycles of cardiopulmonary resuscitation and treatment with amiodarone, lidocaine, magnesium and potassium supplementation, the patient went to the intensive care unit (ICU). While there, the patient had further VF and required haemofiltration for a profound metabolic acidaemia with cardiac rhythm instability. She developed a postcardiac arrest systemic inflammatory response syndrome with episodes of acute pulmonary oedema, profound vasoplegia, hypothermia and coagulopathy. After 5 days in the ICU, the patient was stable enough to be transferred to the ward, with a persistent sinus tachycardia, and was discharged 3 days later with cardiology and psychiatry follow-up. |
13,329 | Electrophysiological and mechanical effects of caffeic acid phenethyl ester, a novel cardioprotective agent with antiarrhythmic activity, in guinea-pig heart. | Caffeic acid phenethyl ester (CAPE) is an active component of propolis that exhibits cardioprotective and antiarrhythmic effects. The detailed mechanisms underlying these effects, however, are not entirely understood. The aim of this study was to elucidate the electromechanical effects of CAPE in guinea-pig cardiac preparations. Intracardiac electrograms, left ventricular (LV) pressure, and the anti-arrhythmic efficacy were determined using isolated hearts. Action potentials of papillary muscles were assessed with microelectrodes, Ca(2+) transients were measured by fluorescence, and ion fluxes were measured by patch-clamp techniques. In a perfused heart model, CAPE prolonged the atrio-ventricular conduction interval, the Wenckebach cycle length, and the refractory periods of the AV node and His-Purkinje system, while shortening the QT interval. CAPE reduced the occurrence of reperfusion-induced ventricular fibrillation and decreased LV pressure in isolated hearts. In papillary muscles, CAPE shortened the action potential duration and reduced both the maximum upstroke velocity and contractile force. In fura-2-loaded single ventricular myocytes, CAPE decreased cell shortening and the Ca(2+) transient amplitude. Patch-clamp experiments revealed that CAPE produced a use-dependent decrease in L-type Ca(2+) current (ICa,L) (IC50=1.1 μM) and Na(+) current (INa) (IC50=0.43 μM), caused a negative-shift of the voltage-dependent inactivation and a delay of recovery from inactivation. CAPE decreased the delayed outward K(+) current (IK) slightly, without affecting the inward rectifier K(+) current (IK1). These results suggest that the preferential inhibition of Ca(2+) inward and Na(+) inward currents by CAPE may induce major electromechanical alterations in guinea-pig cardiac preparations, which may underlie its antiarrhythmic action. |
13,330 | Selective left ventricular sensing lead implantation to overcome undersensing of ventricular fibrillation during implantable cardioverter defibrillator implantation. | Accurate sensing of malignant arrhythmia is critical for the appropriate delivery of therapy from implantable cardioverter defibrillators, and undersensing of ventricular tachyarrhythmias can have catastrophic consequences. Here, we present an unusual case of ventricular fibrillation undersensing from the right ventricular lead at multiple different implantation sites because of very low amplitude voltage signals during induced ventricular fibrillation. A left ventricular sensing electrode was implanted to allow correct sensing and therapy delivery. |
13,331 | Anterior crackles: a neglected sign? | We report on a man, aged 83 years, with chronic heart failure, atrial fibrillation, right ventricular pacing, and worsening exertional dyspnea who was referred for cardiac resynchronization therapy. Detection by anterior chest auscultation of pulmonary crackles during comfortable supine breathing in the context of documented low filling pressures led to the realization that unrecognized pulmonary fibrosis, not congestion, was the principal cause of his shortness of breath. We propose that the incidental finding in chronic heart failure of diffuse anterior crackles during comfortable supine breathing initiate a workup for alternate disorders such as occult pulmonary fibrosis. |
13,332 | [Peculiarities of myocardial remodeling in the acutest phase of experimental myocardial infarction in rats]. | Features of early postischemic cardiac remodeling is well studied both in the clinic and in the experiment. However, the data for this process in the first 60 minutes after occlusion of the coronary vessel in the literature are absent practically. In experiments in rats in which acute myocardial ischemia was reproduced by the simultaneous ligation of the left coronary artery, with the help of echocardiography it is shown that in the first minutes of ischemia in left ventricular systolic function of the heart sharp drops: so, at the 20th minute of ejection fraction (EF) is reduced up 84.5 (79.3-89.2) to 51.7 (50.2-54.4)% - P < 0.05; fraction shortening (FS) is decreased up 52.6 (47.8-59 and 3) to 26.5 (25.9-28.1)% - P < 0.05; a end-systolic dimension (ESD) of the left ventricle is increased up 1.90 (1.70-2.26) to 3.80 (3.50-4.10) mm - P < 0.05, whereas the sham animals were not observed any statistically significant violations of left ventricular systolic function during the observation period (60 minutes). In the period up 20 to 60 min of ischemia is noted a gradual improvement of the relative systolic heart function. At the 60th minute of ischemia all recorded echocardiographic parameters were significantly (P < 0.05) different from those reported in the period from 10 to 20 min of ischemia - EF 62.4 (59.0-64.3)%, FS 33, 7 (31.1-35.2)%, ESD 3.10 (2.80-3.40) mm, etc. Analysis of the results suggests that noted in our experiments the maximum reduction in left ventricular ejection time coincides with the peak of arrhythmogenesis, i.e. with a maximum risk of sudden cardiac death. |
13,333 | The effects of atrial ganglionated plexi stimulation on ventricular electrophysiology in a normal canine heart. | Atrial ganglionated plexi (GP) have been shown to modulate atrial electrophysiology and play an important role in atrial fibrillation initiation and maintenance. The purpose of this study was to investigate the effects of atrial GP stimulation (GPS) on ventricular refractoriness, restitution properties and electrical alternans.</AbstractText>In 12 anesthetized dogs, two multiple electrode catheters were sutured at left and right ventricular free walls for recording. Monophasic action potentials were recorded from six epicardial ventricular sites. Ventricular effective refractory period (ERP), action potential duration (APD) restitution properties and APD alternans were measured at baseline and during GPS.</AbstractText>Compared with baseline, GPS significantly prolonged ventricular ERP and APD at all sites and decreased their spatial dispersions (P < 0.05 for all). GPS also significantly flattened ventricular restitution curves and decreased the maximal slope of restitution curves at each site (P < 0.05 for all). APD alternans occurred at shorter pacing cycle length at each site during GPS when compared with baseline (P < 0.05 for all).</AbstractText>GPS prolonged ventricular ERP, decreased the slope of restitution curves and delayed APD alternans, indicating that GPS may exert a protective role for ventricular arrhythmias.</AbstractText> |
13,334 | Prognostic value of endocardial voltage mapping in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia. | Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may represent the electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D).</AbstractText>We studied 69 consecutive ARVC/D patients (47 males; median age 35 years [28-45]) who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar versus unipolar low-voltage areas of 24.8% (7.2-31.5) and 64.8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar EVM (n=16; 23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19 (27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate implantable cardioverter defibrillator interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (hazard ratio=3.4; 95% confidence interval, 1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (hazard ratio=1.7 per 5%; 95% confidence interval, 1.5-2; P<0.001), whereas the only independent predictor was the bipolar low-voltage electrogram burden (hazard ratio=1.6 per 5%; 95% confidence interval, 1.2-1.9; P<0.001). Patients with normal bipolar EVM had an uneventful clinical course.</AbstractText>The extent of bipolar RV endocardial low-voltage area was a powerful predictor of arrhythmic outcome in ARVC/D, independently of history and RV dilatation/dysfunction. A normal bipolar EVM characterized a low-risk subgroup of ARVC/D patients.</AbstractText> |
13,335 | Mitral annular calcification and incident ischemic stroke in treated hypertensive patients: the LIFE study. | Background Fibro-calcification of the mitral annulus (MAC) has been associated with increased risk of ischemic stroke in general populations. This study was performed to assess whether MAC predicts incidence of ischemic stroke in treated hypertensive patients with left ventricular hypertrophy (LVH). Methods Baseline and follow-up clinical and echocardiographic parameters were assessed in 939 hypertensive patients with electrocardiogram (ECG) LVH participating in the Losartan Intervention for Endpoint reduction in hypertension (LIFE) echocardiography substudy (66±7 years; 42% women; 11% with diabetes) who did not have aortic or mitral valve stenosis or prosthesis. Results MAC was found in 458 patients (49%). Patients with MAC were older (68±7 vs. 65±7 years); were more often women (47% vs. 37%); had higher baseline systolic blood pressure (BP) (175±14 vs. 172±15mm Hg), left atrial diameter (4.0±0.5 vs. 3.8±0.6cm), and left ventricular mass index (58±13 vs. 55±12g/m(2.7)) and included more patients with proteinuria (30% vs. 21%; all P < 0.01). During a mean follow-up of 4.8 years, 58 participants had an ischemic stroke. Risk of incident ischemic stroke was significantly related to presence of MAC (log rank = 9; P < 0.01). In multivariable Cox regression analysis models, MAC was associated with increased risk of ischemic stroke (hazard ratio = 1.78-2.35), independent of age, baseline or time-varying systolic BP, prevalence or incidence of atrial fibrillation, history of previous cerebrovascular disease, and other well-recognized confounders, such as sex, time-varying left ventricular mass, left atrial diameter, and urinary albumin/creatinine ratio (all P < 0.05). Conclusions MAC is common in treated hypertensive patients with ECG LVH and is an independent predictor of incident ischemic stroke. |
13,336 | Prevalence of echocardiographic left-atrial enlargement in hypertension: a systematic review of recent clinical studies. | Left atrial enlargement (LAE) is a marker of hypertensive heart disease associated with increased cardiovascular risk. We reviewed recent literature about the prevalence of LAE, as assessed by echocardiography, to update our information about the clinical relevance of this cardiac phenotype in human hypertension.</AbstractText>We performed a search of MEDLINE using the key words "left atrial enlargement," "left atrial dilatation," "left atrial size," "hypertension," "echocardiography," and "atrial fibrillation" to identify relevant papers. We considered full articles published in English from January 1, 2000 to July 1, 2012 reporting studies involving adult individuals.</AbstractText>We analyzed a total of 15 studies, including 10,141 untreated and treated subjects. LAE was defined according to 11 different criteria (4 studies applied two or three criteria), and its prevalence consistently varied among studies, from 16.0-83.0%, with a prevalence in the pooled population of 32%. A gender-based analysis of 9 studies (8,588 patients) showed the prevalence of LAE as being similar in women and men (OR, 1.23; 95% CI, 0.83-1.83; P = 0.30). Data provided by 10 studies (n = 9,354 patients) showed the prevalence of left-ventricular hypertrophy as being significantly higher in patients with LAE (68.2%) than in their counterparts without LAE (41.8%) (OR, 2.97; 95% CI, 2.68-3.29; P < 0.01).</AbstractText>Our analysis shows that LAE is present in a relevant fraction of the hypertensive population. Because LAE is an independent predictor of cardiovascular events, the accurate detection of this phenotype may improve the evaluation of risk in hypertensive patients.</AbstractText> |
13,337 | Calcium signalling microdomains and the t-tubular system in atrial mycoytes: potential roles in cardiac disease and arrhythmias. | The atria contribute 25% to ventricular stroke volume and are the site of the commonest cardiac arrhythmia, atrial fibrillation (AF). The initiation of contraction in the atria is similar to that in the ventricle involving a systolic rise of intracellular Ca(2+) concentration ([Ca(2+)](i)). There are, however, substantial inter-species differences in the way systolic Ca(2+) is regulated in atrial cells. These differences are a consequence of a well-developed and functionally relevant transverse (t)-tubule network in the atria of large mammals, including humans, and its virtual absence in smaller laboratory species such as the rat. Where T-tubules are absent, the systolic Ca(2+) transient results from a 'fire-diffuse-fire' sequential recruitment of Ca(2+) release sites from the cell edge to the centre and hence marked spatiotemporal heterogeneity of systolic Ca(2+). Conversely, the well-developed T-tubule network in large mammals ensures a near synchronous rise of [Ca(2+)](i). In addition to synchronizing the systolic rise of [Ca(2+)](i), the presence of T-tubules in the atria of large mammals, by virtue of localization of the L-type Ca(2+) channels and Na(+)-Ca(2+) exchanger antiporters on the T-tubules, may serve to, respectively, accelerate changes in the amplitude of the systolic Ca(2+) transient during inotropic manoeuvres and lower diastolic [Ca(2+)](i). On the other hand, the presence of T-tubules and hence wider cellular distribution of the Na(+)-Ca(2+) exchanger may predispose the atria of large mammals to Ca(2+)-dependent delayed afterdepolarizations (DADs); this may be a determining factor in why the atria of large mammals spontaneously develop and maintain AF. |
13,338 | Anatomical characteristics of the left atrial appendage in cardiogenic stroke with low CHADS2 scores. | Strokes develop even in patients with low CHADS₂ scores, and the left atrial appendage (LAA) is the embolic source 90% of the time. We focused on the LAA morphology as a new predictor of strokes.</AbstractText>To clarify the anatomical characteristics of the LAA for risk stratification of strokes in patients with nonvalvular atrial fibrillation (AF) who have low CHADS₂ scores.</AbstractText>Among 80 patients who underwent catheter ablation of AF with contrast-enhanced computed tomography, the LAA characteristics were compared between 30 patients with histories of strokes and 50 age-matched controls. The LAA anatomy was classified into 4 types--"cactus," "cauliflower," "chicken wing," and "windsock"--discriminated by the computed tomography measurements of the length, angle, and number of lobes of the LAA.</AbstractText>The average CHADS₂ score did not differ significantly between patients with stroke and controls (0.8 ± 0.8 vs 0.6 ± 0.7; P = .277). Eight (26.7%) patients with stroke had CHA₂DS₂-VASc scores of 0. The left atrial size, LAA flow velocity, left ventricular function, and serum brain natriuretic peptide level were also unable to predict strokes. However, a "cauliflower" LAA, defined as a main lobe of less than 4 cm long without forked lobes, was significantly more common in patients with stroke (odds ratio 3.857; 95% confidence interval 1.482-10.037; P = .005). The CHA₂DS₂-VASc score-adjusted logistic regression analysis revealed the cauliflower LAA as an independent predictor of a stroke (odds ratio 3.355; 95% confidence interval 1.243-9.055; P = .017).</AbstractText>The LAA anatomy might be useful for predicting strokes in patients with nonvalvular AF who have low CHADS₂ scores.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,339 | [Survival of out-hospital cardiac arrests attended by a mobile intensive care unit in Asturias (Spain) in 2010]. | To evaluate attendance timings, out- and in-hospital characteristics, and survival of cardiac arrests attended by an advanced life support unit in Asturias (Spain) in 2010. Factors related to survival upon admission and at discharge were also analyzed.</AbstractText>A retrospective, observational trial was carried out involving a cohort of out-hospital cardiac arrests (OHCA) occurring between 1 January 2010 and 31 December 2010, with one year of follow-up from OHCA.</AbstractText>Health Care Area IV of the Principality of Asturias, with a population of 342,020 in 2010.</AbstractText>All patients with OHCA and attended by an advanced life support unit were considered.</AbstractText>Demographic data, the etiology of cardiac arrest, bystander cardiopulmonary resuscitation (CPR), attendance timings and survival upon admission, at discharge and after one year.</AbstractText>A total of 177 OHCA were included. Of these, 120 underwent CPR by the advanced life support team. Sixty-six of these cases (55%) were caused by presumed heart disease. A total of 63 patients (52.5%) recovered spontaneous circulation, and 51 (42.5%) maintained circulation upon admission to hospital. Thirteen patients (10.8%) were discharged alive. After one year, 11 patients were still alive (9.2%) - 9 of them (7.5%) with a Cerebral Performance Category (CPC) score of 1. Ventricular fibrillation and short attendance timings were related to increased survival.</AbstractText>The survival rate upon admission was better than in other series and similar at discharge. Initial rhythm and attendance timings were related. Public automated external defibrillators (AED) were not used, and bystander CPR was infrequent.</AbstractText>Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.</CopyrightInformation> |
13,340 | In situ lung perfusion is a valuable tool to assess lungs from donation after circulatory death donors category I-II. | Donations after circulatory death (DCD) lung grafts are an alternative to extend the donor pool in lung transplantation. This study investigates the use of an in situ lung perfusion system (ISLP) in the donor to evaluate category I-II lungs. Pigs were sacrificed by ventricular fibrillation. All animals underwent 20 min of cardiopulmonary resuscitation and 5 min hands-off period after which heparin was administered. In group [WI-1], this was followed by 1 h of warm ischemia (WI) and 2 h of topical cooling (TC). In group [WI-2], 2 h of WI was followed by 1 h of TC. In group [WI-0], there was a minimal period of WI and no TC. In all three groups, the lungs were then evaluated during 60 min with ISLP. [WI-0] lungs showed a significantly higher compliance and Δ PO2 /FiO2 compared with [WI-1] and [WI-2]. PaCO2 and lactate production were higher in [WI-2] versus [WI-0]. Wet/Dry weight ratio was significantly higher in [WI-2] compared with [WI-0] in two lung biopsy locations. A high W/D weight ratio was correlated with a lower compliance, higher lactate production, and a higher PaCO2 . ISLP is an effective way to assess the quality of lungs from category I-II DCD donors. |
13,341 | Differences in clinical and echocardiographic parameters between paroxysmal and persistent atrial flutter in the AURUM 8 study: targets for prevention of persistent arrhythmia? | Cavotricuspid isthmus-dependent atrial flutter (AFL) can occur in a paroxysmal or persistent pattern. The aim of this study was to identify clinical, echocardiographic, and electrophysiological risk factors independently associated with persistence of AFL.</AbstractText>Patients of the recently published AURUM 8 study with paroxysmal versus persistent AFL were compared with respect to clinical and echocardiographic baseline characteristics as well as procedural parameters. The AURUM 8 study is a randomized, multicenter clinical trial comparing the efficacy and safety of gold versus platinum-iridium 8-mm-tip ablation. AFL was paroxysmal in 218 patients and persistent in 210 patients.</AbstractText>Univariate analysis revealed that patients with persistent AFL had higher New York Heart Association class (P = 0.002), shorter time since 1st AFL episode (median 0.18 vs 0.34, P = 0.037), a higher prevalence of previous coronary artery bypass grafting surgery (17% vs 9%, P = 0.02), left ventricular hypertrophy (17% vs 8%, P = 0.005), dyspnea during AFL (P < 0.001), mitral regurgitation (P = 0.002), tricuspid regurgitation (P = 0.049), and pulmonary hypertension (P = 0.01). Palpitations during AFL were less frequent in patients with persistent AFL (P = 0.001). Multivariate analysis revealed that age, weight, AFL diagnosis after initiation of class IC or III antiarrhythmic drugs for atrial fibrillation, history of left ventricular hypertrophy, dyspnea during AFL and mitral regurgitation on echocardiography were significant independent variables associated with persistent AFL. A history of atrial fibrillation and palpitations during AFL were independently associated with paroxysmal AFL.</AbstractText>We were able to identify clinical and echocardiographic risk factors associated with persistence of typical AFL. Treatment of these risk factors can potentially not only prevent the transition from paroxysmal to persistent AFL, but maybe also the development or initiation of AFL in general.</AbstractText>©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,342 | Glutathione oxidation unmasks proarrhythmic vulnerability of chronically hyperglycemic guinea pigs. | Chronic hyperglycemia in type-1 diabetes mellitus is associated with oxidative stress (OS) and sudden death. Mechanistic links remain unclear. We investigated changes in electrophysiological (EP) properties in a model of chronic hyperglycemia before and after challenge with OS by GSH oxidation and tested reversibility of EP remodeling by insulin. Guinea pigs survived for 1 mo following streptozotocin (STZ) or saline (sham) injection. A treatment group received daily insulin for 2 wk to reverse STZ-induced hyperglycemia (STZ + Ins). EP properties were measured using high-resolution optical action potential mapping before and after challenge of hearts with diamide. Despite elevation of glucose levels in STZ compared with sham-operated (P = 0.004) and STZ + Ins (P = 0.002) animals, average action potential duration (APD) and arrhythmia propensity were not altered at baseline. Diamide promoted early (<10 min) formation of arrhythmic triggers reflected by a higher arrhythmia scoring index in STZ (P = 0.045) and STZ + Ins (P = 0.033) hearts compared with sham-operated hearts. APD heterogeneity underwent a more pronounced increase in response to diamide in STZ and STZ + Ins hearts compared with sham-operated hearts. Within 30 min, diamide resulted in spontaneous incidence of ventricular tachycardia and ventricular fibrillation (VT/VF) in 3/6, 2/5, 1/5, and 0/4 STZ, STZ + Ins, sham-operated, and normal hearts, respectively. Hearts prone to VT/VF exhibited greater APD heterogeneity (P = 0.010) compared with their VT/VF-free counterparts. Finally, altered EP properties in STZ were not rescued by insulin. In conclusion, GSH oxidation enhances APD heterogeneity and increases arrhythmia scoring index in a guinea pig model of chronic hyperglycemia. Despite normalization of glycemic levels by insulin, these proarrhythmic properties are not reversed, suggesting the importance of targeting antioxidant defenses for arrhythmia suppression. |
13,343 | Ischemic post-conditioning and vasodilator therapy during standard cardiopulmonary resuscitation to reduce cardiac and brain injury after prolonged untreated ventricular fibrillation. | We investigated the effects of ischemic postconditioning (IPC) with and without cardioprotective vasodilatory therapy (CVT) at the initiation of cardiopulmonary resuscitation (CPR) on cardio-cerebral function and 48-h survival.</AbstractText>Prospective randomized animal study. Following 15 min of ventricular fibrillation, 42 Yorkshire farm pigs weighing an average of 34 ± 2 kg were randomized to receive standard CPR (SCPR, n=12), SCPR+IPC (n=10), SCPR+IPC+CVT (n=10), or SCPR+CVT (n=10). IPC was delivered during the first 3 min of CPR with 4 cycles of 20s of chest compressions followed by 20-s pauses. CVT consisted of intravenous sodium nitroprusside (2mg) and adenosine (24 mg) during the first minute of CPR. Epinephrine was given in all groups per standard protocol. A transthoracic echocardiogram was obtained on all survivors 1 and 4h post-ROSC. The brains were extracted after euthanasia at least 24h later to assess ischemic injury in 7 regions. Ischemic injury was graded on a 0-4 scale with (0=no injury to 4 ≥ 50% neural injury). The sum of the regional scores was reported as cerebral histological score (CHS). 48 h survival was reported.</AbstractText>Post-resuscitation left ventricular ejection (LVEF) fraction improved in SCPR+CVT, SCPR+IPC+CVT and SCPR+IPC groups compared to SCPR (59% ± 9%, 52% ± 14%, 52% ± 14% vs. 35% ± 11%, respectively, p<0.05). Only SCPR+IPC and SCPR+IPC+CVT, but not SCPR+CVT, had lower mean CHS compared to SCPR (5.8 ± 2.6, 2.8 ± 1.8 vs. 10 ± 2.1, respectively, p<0.01). The 48-h survival among SCPR+IPC, SCPR+CVT, SCPR+IPC+CVT and SCPR was 6/10, 3/10, 5/10 and 1/12, respectively (Cox regression p<0.01).</AbstractText>IPC and CVT during standard CPR improved post-resuscitation LVEF but only IPC was independently neuroprotective and improved 48-h survival after 15 min of untreated cardiac arrest in pigs.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,344 | Long-term follow-up of a pediatric cohort with short QT syndrome. | The purpose of this study was to define the clinical characteristics and long-term follow-up of pediatric patients with short QT syndrome (SQTS).</AbstractText>SQTS is associated with sudden cardiac death. The clinical characteristics and long-term prognosis in young patients have not been reported.</AbstractText>This was an international case series involving 15 centers. Patients were analyzed for electrocardiography characteristics, genotype, clinical events, Gollob score, and efficacy of medical or defibrillator (implantable cardioverter-defibrillator [ICD]) therapy. To assess the possible prognostic value of the Gollob score, we devised a modified Gollob score that excluded clinical events from the original score.</AbstractText>Twenty-five patients 21 years of age or younger (84% males, median age: 15 years, interquartile range: 9 to 18 years) were followed up for 5.9 years (interquartile range: 4 to 7.1 years). Median corrected QT interval for heart rate was 312 ms (range: 194 to 355 ms). Symptoms occurred in 14 (56%) of 25 patients and included aborted sudden cardiac death in 6 patients (24%) and syncope in 4 patients (16%). Arrhythmias were common and included atrial fibrillation (n = 4), ventricular fibrillation (n = 6), supraventricular tachycardia (n = 1), and polymorphic ventricular tachycardia (n = 1). Sixteen patients (84%) had a familial or personal history of cardiac arrest. A gene mutation associated with SQTS was identified in 5 (24%) of 21 probands. Symptomatic patients had a higher median modified Gollob score (excluding points for clinical events) compared with asymptomatic patients (5 vs. 4, p = 0.044). Ten patients received medical treatment, mainly with quinidine. Eleven of 25 index cases underwent ICD implantation. Two patients had appropriate ICD shocks. Inappropriate ICD shocks were observed in 64% of patients.</AbstractText>SQTS is associated with aborted sudden cardiac death among the pediatric population. Asymptomatic patients with a Gollob score of <5 remained event free, except for an isolated episode of supraventricular tachycardia, over an average 6-year follow-up. A higher modified Gollob score of 5 or more was associated with the likelihood of clinical events. Young SQTS patients have a high rate of inappropriate ICD shocks.</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,345 | The effect of routine magnesium supplementation on fetal cardiac time intervals: a fetal magnetocardiographic study. | Magnesium deficiency in pregnancy is frequent, and in consequence magnesium supplementation is widely used. As magnesium crosses the placental barrier and since the fetal kidney does not excrete magnesium as efficiently as the mature kidney, effects on fetal cardiac time intervals are probable, but still unknown.</AbstractText>Sixty pregnant women were included in an observational study: 31 patients received oral routine magnesium supplementation. In addition to routine fetal echocardiography, fetal magnetocardiography (fMCG) was used to investigate electrophysiological rhythm patterns with high temporal resolution. fMCG tracings were analyzed according to a predefined procedure for fetal cardiac time interval (CTI)-detection. fCTI findings (P-wave, PQ-segment, PR-interval, QRS complex, ST segment, T-wave and QTc interval) were registered.</AbstractText>Significant widening of the QRS-complex (p=0.004) was demonstrated in fetuses whose mothers received magnesium supplementation (240 mg/day) relative to the control group.</AbstractText>Magnesium exposed fetuses demonstrated a prolonged ventricular arousal, but healthy neonatal outcome was found in all exposed fetuses. Although fMCG is a preclinical method and limited in its availability, the procedure could help to monitor fetuses.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,346 | Extracorporeal membrane oxygenation to support cardiopulmonary resuscitation in a sheep model of refractory ischaemic cardiac arrest. | Survival after out-of-hospital cardiac arrest remains limited. It is therefore imperative to develop new resuscitation techniques. We aimed to determine the potential role of extracorporeal membrane oxygenation assisted CPR (ECPR) in an animal model of refractory ischaemic cardiac arrest.</AbstractText>Twelve sheep were assigned to either ECPR (n=6) or 'conventional' (n=6) resuscitation. All sheep had coronary occlusion, followed by induction of ventricular fibrillation (VF). CPR was than commenced for 10 min in both groups, followed by randomisation to ECPR or CPR for a further 10 min. At 23 min post induction of VF, advanced life support measures were commenced with direct cardioversion, adrenaline and amiodarone. Outcomes measures included rates of return of spontaneous circulation (ROSC), and analysis of VF wave form.</AbstractText>Baseline haemodynamics were similar between the two groups. CPR consistently produced coronary perfusion pressures (CPP) greater than 15 mmHg in both groups, with significantly increased CPP post commencement of ECMO in the ECPR group (17.84±2 mmHg vs 22.94±3 mmHg, p=0.04). Number of shocks, pH, lactate and oxygenation were also comparable. Significantly greater rates of ROSC were seen in the ECPR sheep, 3/6 (50%) vs 0/6 (0%) (p=0.032), which was also associated with significantly increased VF amplitude measures (0.51±0.08 mV vs 0.42±0.06 mV, p=0.04).</AbstractText>This study indicates that ECPR increases return of circulation and coronary perfusion pressure in a sheep model of ischaemic VF arrest. Our findings have supported the development of a pilot trial into the effectiveness and feasibility of ECPR in the clinical setting.</AbstractText>Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
13,347 | Predicting favourable outcomes in the setting of radiofrequency catheter ablation of long-standing persistent atrial fibrillation: a pilot study assessing the value of left atrial appendage peak flow velocity. | Catheter ablation is an effective and potentially curative treatment in patients with atrial fibrillation (AF).</AbstractText>To test the hypothesis that left atrial appendage peak flow velocity (LAV) assessed by echocardiography can accurately predict successful catheter ablation as well as favourable outcome in the setting of long-standing persistent AF.</AbstractText>This prospective pilot study enrolled 40 patients with long-standing persistent AF (age 60 ± 11 years; persistence of AF 4.2 ± 2 years) who underwent a first catheter ablation procedure using a standardized sequential stepwise protocol. LAV was assessed before the catheter ablation procedure along with classical factors (age, sex, left atrial area, AF cycle length, AF duration and left ventricular ejection fraction), all of which were tested using logistic regression for ability to predict restoration of sinus rhythm during catheter ablation as well as absence of recurrence during a 1-year follow-up.</AbstractText>Eighteen patients (45%) experienced AF termination during the procedure and 18 patients (45%) did not develop any recurrence during the first 12 months. Multivariable analysis demonstrated that high LAV (>0.3 m/s) was the only independent predictor of AF termination (odds ratio 5.91, 95% confidence interval 1.06-32.88; P=0.04) and absence of recurrence at 1 year (odds ratio 4.33, 95% confidence interval 1.05-17.81; P=0.04).</AbstractText>This pilot study demonstrated the feasibility and importance of LAV measurement in the setting of long-standing persistent AF to predict successful catheter ablation and favourable mid-term outcome.</AbstractText>Copyright © 2012. Published by Elsevier Masson SAS.</CopyrightInformation> |
13,348 | Slower heart rate and altered rate dependence of ventricular repolarization in patients with lone atrial fibrillation. | Electrophysiological alterations in atrial fibrillation (AF) may be genetically based and may lead to changes in ventricular repolarization. Short QT syndrome is a rare channelopathy with abbreviated ventricular repolarization and a propensity for AF.</AbstractText>To determine if minor unrecognized forms of short QT syndrome can explain some cases of lone AF.</AbstractText>We prospectively compared QT intervals in 66 patients with idiopathic lone AF and 132 age- and sex-matched controls. QT intervals were measured during sinus rhythm in each of the 12 surface electrocardiogram leads and corrected using Bazett's formula (QTc). QT intervals were also corrected using other formulae. Uncorrected QT and heart rate regression lines were compared between AF patients and controls.</AbstractText>AF patients presented with a slower resting heart rate (64 ± 10 beats per minute [bpm] vs 69 ± 9 bpm; P=0.0006). QTc intervals were shorter in AF patients in 11/12 electrocardiogram leads (significant in 7/12, borderline in 2/12; mean QTc 381 ± 21 ms vs 388 ± 22 ms; P=0.02). QTc intervals were also shorter in AF patients, significantly or not, using other correction formulae. For similar heart rates, uncorrected QT intervals were shorter in patients when heart rates were greater than 70 bpm and longer when heart rates were less than 60 bpm. AF patients displayed steeper QT/heart rate regression line slopes than controls (P=0.009).</AbstractText>Heart rate is significantly slower and the rate dependence of ventricular repolarization is significantly altered in patients with lone AF compared with controls. Further study is warranted to determine if AF induces subsequent ventricular repolarization changes or if these modifications are caused by an underlying primary electrical disease.</AbstractText>Copyright © 2012 Elsevier Masson SAS. All rights reserved.</CopyrightInformation> |
13,349 | Higher degree of left atrial structural remodeling in patients with atrial fibrillation and left ventricular systolic dysfunction. | Catheter ablation significantly improves the left ventricular (LV) function in patients with atrial fibrillation (AF) and LV systolic dysfunction. In this study, we compared the degree of left atrial structural remodeling (LA-SRM) in patients with normal versus reduced LV ejection fraction (LVEF). We also studied the impact of LA-SRM on LVEF improvement in patients undergoing ablation of AF.</AbstractText>We categorized 384 patients into 2 groups based on their cardiac function: reduced LVEF group (LVEF ≤50%; n = 105) and normal LVEF group (LVEF > 50%; n = 279). LVEF was determined prior and mean 8 ± 3 months after catheter ablation for AF. Percentage of LA-SRM was quantified using LGE-MRI and patients were classified into 4 groups based on the amount of structural remodeling in their LA wall: minimal ≤ 5%, mild = 5-20%, moderate = 20-35%, and extensive ≥ 35%. The average preablation LA-SRM (21.5 ± 13.2% vs 15.4 ± 10.0%; P < 0.001) was significantly higher in reduced LVEF group than normal LVEF group. Among the 105 patients with reduced LVEF, while there was a modest 11.7 ± 8.4% average increase in LVEF following ablation, the greatest increase was seen in patients with less extensive LA-SRM (minimal = 19.3 ± 5.1%, n = 3, P = 0.02 and mild = 16.6 ± 9.9%, n = 48, P < 0.001). Patients with moderate and extensive fibrosis had an average EF improvement of 8.7 ± 11.1% and 2.8 ± 6.4%, respectively (n = 39, P < 0.001 and n = 15, P = 0.11, respectively).</AbstractText>Patients with LV systolic dysfunction displayed a comparatively greater LA-SRM than patients with normal LVEF. Patients with lesser LA-SRM experienced a greater improvement in LVEF after catheter ablation for AF.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,350 | Noninvasive panoramic mapping of human atrial fibrillation mechanisms: a feasibility report. | Recent developments in body surface mapping and computer processing have allowed noninvasive mapping of atrial activation responsible for various cardiac arrhythmias with increasingly greater resolution. We developed specific algorithms to identify localized sources and atrial propagation occurring simultaneously during ongoing atrial fibrillation (AF).</AbstractText>We report the feasibility of noninvasive panoramic mapping of human AF mechanisms and its validation by successful ablation. We used a commercially available mapping system using an array of 252 body surface electrodes and noncontrast thoracic CT scan to obtain high-resolution images of the biatrial geometry and the relative electrode positions. On the surface unipolar electrograms acquired during AF we developed specific signal-analysis process combining filtering, wavelet transform, and phase mapping. At least 5 windows with spontaneous, long ventricular pauses were selected for mapping. The incidence, location and characteristics of localized sources (foci and rotors) were assessed on the cumulative duration of all recorded windows. In a patient with paroxysmal AF, noninvasive maps showed multiple single or repetitive discharges from 3 pulmonary veins (PVs), a rotor meandering along the right venous ostia, and their mutual interplay. All areas outside the left posterior wall were passively activated. AF terminated during isolation of right PV. In a patient with persistent AF for 7 months, a rotor was identified recurrently, drifting in the left atrial inferior and posterior wall and in the roof. It was not stationary for more than 2 rotations. The right atrial free wall was activated over the Bachman's bundle by a passive wavefront propagating in a counterclockwise pattern. Ablation at the rotor locations abruptly converted AF into atrial tachycardia after 10 minutes of radiofrequency application. Further mapping and ablation confirmed a counterclockwise cavotricuspid isthmus-dependent flutter.</AbstractText>This report demonstrates the feasibility of noninvasive panoramic mapping of AF in identifying active sources, which include unstable rotors and PV foci, and its validation by ablation results.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,351 | Impaired ventricular repolarization dynamics in patients with early repolarization syndrome. | Almost all current investigations on early repolarization syndrome (ERS) have focused on the J-wave characteristics and ST-segment configuration; however, few have reported on ventricular repolarization indexes in ERS.</AbstractText>A total of 145 subjects were enrolled: 10 ERS patients, 45 uneventful ER pattern (ERP) subjects, and 90 healthy controls without J waves or ST-segment elevation. Ambulatory ECG-derived parameters (QT, QTc(B), QTc(F), T peak-Tend(Tpe), and QT/RR slope) were measured and statistically compared. Among the groups, there was no significant difference in the average QT and QTc(B); however, ERS patients had the shortest QTc(F) and longest Tpe (QTc(F): 396.2 ± 19 vs 410.4 ± 20 vs 419.2 ± 19 milliseconds, P = 0.036, Tpe: 84.9 ± 12 vs 70.4 ± 11 vs 66.9 ± 15 milliseconds, P < 0.001, for the ERS, ERP, and control groups, respectively). Importantly, the 24-hour QT/RR slope was significantly smaller in the ERS than ERP and control groups (QT/RR: 0.105 ± 0.01 vs 0.154 ± 0.02 vs 0.161 ± 0.03, respectively; P < 0.001). When analyzing the diurnal and nocturnal QT/RR slopes, ERS patients had small diurnal and nocturnal QT/RR slopes while the ERP and control groups had large diurnal and small nocturnal QT/RR slopes (diurnal QT/RR: 0. 077 ± 0.01 vs 0.132 ± 0.03 vs 0.143 ± 0.03, P < 0.001; nocturnal QT/RR: 0.093 ± 0.02 vs 0.129 ± 0.03 vs 0.130 ± 0.04, P = 0.02 in the ERS, ERP, and control groups, respectively).</AbstractText>ERS patients had a continuously depressed diurnal and nocturnal adaptation of the QT interval to the heart rate. Such abnormal repolarization dynamics might provide a substrate for reentry and be an important element for developing ventricular fibrillation in the ERS cohort.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,352 | Role of tumor necrosis factor-α in the pathogenesis of atrial fibrosis and development of an arrhythmogenic substrate. | Although tumor necrosis factor-α (TNF-α) levels are increased in patients with atrial fibrillation (AF), its role in the pathogenesis of AF is unclear. We investigated whether direct delivery of TNF-α could induce atrial fibrosis.</AbstractText>TNF-α (4 μg/kg) was injected into the tail vein of 20 male Swiss albino mice (TNF group) and saline into 20 control mice (CON group). The dose was carefully chosen to avoid any significant decrease in left ventricular (LV) function. Animals were killed after 16 weeks and their atria examined for fibrosis. We found increased atrial fibrosis in the TNF group compared with the CON group [372.8±21.5 arbitrary units (a.u.) vs. 56.9±6.5 a.u., respectively, mean±SEM; P<0.0001] and decreased connexin-40 immunofluorescence [7.5±0.4 a.u vs. 40.4±1.9 a.u, respectively; P<0.0001]. Transforming growth factor-β [TGF-β: 95.6±1.8 a.u vs. 29.4±5.8 a.u; P<0.001], α-smooth muscle actin (α-SMA: 97.9±13.0 a.u vs. 50.1±18.5 a.u; P<0.05] and matrix metalloproteinase 2 (MMP-2)/GAPDH levels [157.3±26.4 a.u vs. 105.8±13.3 a.u; P<0.05] were also increased in the TNF group.</AbstractText>TNF-α is involved in the pathogenesis of atrial fibrosis and altered connexin-40 expression in mice through the TGF-β signaling pathway, activation of myofibroblasts and increased secretion of MMPs. Collectively, these changes may contribute to the arrhythmogenic substrate and development of AF. </AbstractText> |
13,353 | Impact of defibrillation testing on predicted ICD shock efficacy: implications for clinical practice. | Lack of consensus regarding defibrillation testing methods for implantable cardioverter-defibrillators relates to risks of repeated fibrillation episodes.</AbstractText>To provide recommendations for testing protocols, repeating testing of patients with high defibrillation threshold (DFT), and interpreting testing after implantable cardioverter-defibrillator system revision.</AbstractText>We constructed a computer model of defibrillation probability-of-success curves using data from 564 patients. Then, we compared 13 safety margin (SM) or DFT protocols in 50,000 simulated patients to identify those with the best balance of sensitivity and predictive value for detecting patients at high risk for failed defibrillation. Conditional retesting of patients with high DFT was simulated, both without and with revision that lowered defibrillation energy by one-third.</AbstractText>SM protocols were more efficient than DFT protocols; 2/2 successes at 20 J or 1/1 at 16 J performed best. Patients who failed testing had a mean probability of defibrillation of 94% at 35 J, but great uncertainty regarding that probability (range 67.0%-100%). When they repeated testing, 62% passed, with 48% owing to regression to the mean. If system revision was performed before retesting, 84% passed; the fraction of patients at high risk reduced (4.7% to 2.7%, with 43% relative reduction); but 3.5% underwent unnecessary revisions. Testing and revision of patients with high DFT benefitted 2.5% of the patients.</AbstractText>SM protocols are superior to DFT protocols for implant testing. For patients who fail testing, there is substantial uncertainty in defibrillation efficacy. After a system revision that does not alter defibrillation efficacy, 62% of these patients pass retesting.</AbstractText>Copyright © 2013. Published by Elsevier Inc.</CopyrightInformation> |
13,354 | The Impact of Sub-valvular Apparatus Preservation on Prosthetic Valve Dysfunction During Mitral Valve Replacement. | Sub-valvular apparatus preservation (SAP) during mitral valve replacement (MVR) is not a new concept. Some surgeons prefer to excise the apparatus.</AbstractText>The aim of this study was to reduce the risk of prosthetic valve dysfunction.</AbstractText>This retrospective study included 151 patients with the mean age of 46 years who underwent MVR (Female/male = 93/58). In the group I consisting of 39 patients, MVR with chordae preservation was performed (Bi-leaflet preservation = 20; posterior leaflet preservation = 19). In the group II consisting of 112 patients, sub-valvular apparatus was resected completely during MVR. Preoperative patients' characteristics, including age, sex, functional status, left ventricular ejection fraction, and end-diastolic or end-systolic dimensions were statistically similar in both groups. Mean follow-up period was 60.3 ± 26 months.</AbstractText>The improvement of functional status was seen in almost all survivors but was more obvious in the group I. In early follow-up, 56.4% of group I cases and 44.1% of group II patients were classified as New York Heart Association class I. These rates were 84.2% and 71.2% in mid-term follow-up, respectively (P < 0.001). Mortality rate was significantly lower in the group I (2.6%) compared to the group II (8.9%) (P = 0.03). There was a trend for higher frequency of postoperative atrial fibrillation in the group II compared to that in the group I (52.7% vs. 38.5%, P = 0.12).The incidence of prosthetic valve dysfunction (PVD) was 5.1% in the group I and 4.5% in the group II, but this difference was not statistically significant (P = 0.56).</AbstractText>Preservation of mitral annulus and papillary muscle continuity may enhance post- MVR cardiac performance with low mortality and morbidity rates. The risk of PVD was not significantly higher than conventional MVR in our series.</AbstractText> |
13,355 | Innovations in heart rhythm disturbances: cardiac electrophysiology, arrhythmias, and cardiac pacing. | This article reviews the most relevant articles published in 2012 in the field of arrhythmias, on subjects that include clinical arrhythmology, ablation, cardiac pacing, and the genetics of sudden cardiac death. |
13,356 | The stability of electrically induced ventricular fibrillation. | The first recorded heart rhythm for cardiac arrest patients can either be ventricular fibrillation (VF) which is treatable with a defibrillator, or asystole or pulseless electrical activity (PEA) which are not. The time course for the deterioration of VF to either asystole or PEA is not well understood. Knowing the time course of this deterioration may allow for improvements in emergency service delivery. In addition, this may improve the diagnosis of possible electrocutions from various electrical sources including utility power, electric fences, or electronic control devices (ECDs) such as a TASER(®) ECD. We induced VF in 6 ventilated swine by electrically maintaining rapid cardiac capture, with resulting hypotension, for 90 seconds. No circulatory assistance was provided. They were then monitored for 40 minutes via an electrode in the right ventricle. Only 2 swine remained in VF; 3 progressed to asystole; 1 progressed to PEA. These results were used in a logistic regression model. The results are then compared to published animal and human data. The median time for the deterioration of electrically induced VF in the swine was 35 minutes. At 24 minutes VF was still maintained in all of the animals. We conclude that electrically induced VF is long-lived--even in the absence of chest compressions. |
13,357 | Essentials of low-power electrocution: established and speculated mechanisms. | Even though electrocution has been recognized--and studied--for over a century, there remain several common misconceptions among medical professional as well as lay persons. This review focuses on "low-power" electrocutions rather than on the "high-power" electrocutions such as from lightning and power lines. Low-power electrocution induces ventricular fibrillation (VF). We review the 3 established mechanisms for electrocution: (1) shock on cardiac T-wave, (2) direct induction of VF, and (3) long-term high-rate cardiac capture reducing the VF threshold until VF is induced. There are several electrocution myths addressed, including the concept--often taught in medical school--that direct current causes asystole instead of VF and that electrical exposure can lead to a delayed cardiac arrest by inducing a subclinical ventricular tachycardia (VT). Other misunderstandings are also discussed. |
13,358 | A ventricular activity cancellation algorithm based on event synchronous adaptive filter for single-lead electrocardiograms. | Recently, it has become very important to analyze atrial activity (AA) and to detect arrhythmic AAs and, for this, complete ventricular activity (VA) cancellation is prerequisite. There have been several VA cancellation algorithms for multi-lead ECG but VA cancellation algorithm for single-lead is quite a few. In this study, we have modeled thoracic ECG and, based on this model, proposed a novel VA cancellation algorithm based on event synchronous adaptive filter (ESAF). In this ESAF, the AF ECG was treated as a primary input and event-synchronous impulse train (ESIT) as a reference. And, ESIT was generated so to be synchronized with the ventricular activity by detecting QRS complex. To evaluate the performance, it was applied to the AA estimation problem in atrial fibrillation electrocardiograms. As results, even with low computational cost, this ESAF based algorithm showed better performance than the ABS method and comparable performance to algorithm based on PCA (principal component analysis) or SVD (singular value decomposition). We also proposed an expanded version of ESAF for some AF ECGs with bimorphic VAs and this also showed reasonable performance. Ultimately, our proposed algorithm was found to estimate AA precisely even though it is possible to implement in real-time. We expect our algorithm to replace the most widely used method, that is, the ABS (averaged beat subtraction) method. |
13,359 | Sequential algorithm for the detection of the shockable rhythms in electrocardiogram. | We suggest a sequential algorithm for the detection of the ventricular fibrillation (VF) and ventricular tachycardia (VT) of a rate above 180 bpm, so called shockable rhythms. The built-in algorithm for ECG analysis embedded in the portable bio-signal sensing module is aimed to discriminate between shockable and non-shockable rhythms and its accuracy is analyzed. An algorithm for VF/VT detection is proposed to analyze every 1 s ECG episode using the past 8 s episodes. The method is tested with 844,587 ECG episodes from the widely accepted databases. A sensitivity of 86.8 % and a specificity of 99.4 % were obtained and compared with the previous results. |
13,360 | Single camera system for multi-wavelength fluorescent imaging in the heart. | Optical mapping has been a powerful method to measure the cardiac electrophysiological phenomenon such as membrane potential(V(m)), intracellular calcium(Ca(2+)), and the other electrophysiological parameters. To measure two parameters simultaneously, the dual mapping system using two cameras is often used. However, the method to measure more than three parameters does not exist. To exploit the full potential of fluorescence imaging, an innovative method to measure multiple, more than three parameters is needed. In this study, we present a new optical mapping system which records multiple parameters using a single camera. Our system consists of one camera, custom-made optical lens units, and a custom-made filter wheel. The optical lens units is designed to focus the fluorescence light at filter position, and form an image on camera's sensor. To obtain optical signals with high quality, efficiency of light collection was carefully discussed in designing the optical system. The developed optical system has object space numerical aperture(NA) 0.1, and image space NA 0.23. The filter wheel was rotated by a motor, which allows filter switching corresponding with needed fluorescence wavelength. The camera exposure and filter switching were synchronized by phase locked loop, which allow this system to record multiple fluorescent signals frame by frame alternately. To validate the performance of this system, we performed experiments to observe V(m) and Ca(2+) dynamics simultaneously (frame rate: 125fps) with Langendorff perfused rabbit heart. Firstly, we applied basic stimuli to the heart base (cycle length: 500ms), and observed planer wave. The waveforms of V(m) and Ca(2+) show the same upstroke synchronized with cycle length of pacing. In addition, we recorded V(m) and Ca(2+) signals during ventricular fibrillation induced by burst pacing. According to these experiments, we showed the efficacy and availability of our method for cardiac electrophysiological research. |
13,361 | Development of a patch type embedded cardiac function monitoring system using dual microprocessor for arrhythmia detection in heart disease patient. | A patch type embedded cardiac function monitoring system was developed to detect arrhythmias such as PVC (Premature Ventricular Contraction), pause, ventricular fibrillation, and tachy/bradycardia. The overall system is composed of a main module including a dual processor and a Bluetooth telecommunication module. The dual microprocessor strategy minimizes power consumption and size, and guarantees the resources of embedded software programs. The developed software was verified with standard DB, and showed good performance. |
13,362 | Defibrillation success rates for electrically-induced fibrillation: hair of the dog. | Accidental electrocutions kill about 1000 individuals annually in the USA alone. There has not been a systematic review or modeling of elapsed time duration defibrillation success rates following electrically-induced VF. With such a model, there may be an opportunity to improve the outcomes for industrial electrocutions and further understand arrest-related-deaths where a TASER(®) electrical weapon was involved. We searched for MedLine indexed papers dealing with defibrillation success following electrically-induced VF with time durations of 1 minute or greater post VF induction. We found 10 studies covering a total of 191 experiments for defibrillation of electrically-induced VF for post-induction durations out to 16 minutes including 0-9 minutes of pre-shock chest compressions. The results were fitted to a logistic regression model. Total minutes of VF and use of pre-shock chest compressions were significant predictors of success (p &#60; .00005 and p= .003 respectively). The number of minutes of chest compressions was not a predictor of success. With no compressions, the 90% confidence of successful defibrillation is reached at 6 minutes and the median time limit for success is 9.5 minutes. However, with pre-shock chest compressions, the modeled data suggest a 90% success rate at 10 minutes and a 50% rate at 14 minutes.1. |
13,363 | Hysteresis in DI independent mechanisms in threshold for transition between 1:1 and 2:2 rhythms in pigs. | Previous studies have shown hysteresis in transition from 1:1 to 2:2 rhythms in action potential durations (APD) during decreasing and increasing cycle length pacing. As cycle lengths were constant, when alternans of APD occurred, so did of preceding diastolic intervals (DIs), which engaged the restitution mechanism, i.e. dependence of APD on preceding DI, making it impossible to determine whether the hysteresis originates from the DI independent or dependent mechanism. By using pacing with explicit control of DI, in the present study we investigated whether hysteresis in activation threshold exists in DI independent mechanism of alternans of APD. Transmembrane potentials were recorded from the left ventricles of 6 farm pigs, and the state transition was obtained from two pacing protocols where DIs decreased and increased in steps of 10 msec between 50 and 20 msec with 30 (15) beats at each DI level. Results showed hysteresis: for the 30 (15) beats protocol, onset and termination of alternans occurred at 27 (33) and 47 (49) msec DIs; average alternans amplitude was 22 (13) and 26 (15) msec for decreasing and increasing DIs. Because constant DI pacing was used, restitution dependent effect was eliminated, therefore, observation of hysteresis in our results suggests that restitution independent mechanisms such as activation memory also contribute to the hysteresis in this state transition. |
13,364 | Human electrophysiological and pharmacological properties of XEN-D0101: a novel atrial-selective Kv1.5/IKur inhibitor. | The human electrophysiological and pharmacological properties of XEN-D0101 were evaluated to assess its usefulness for treating atrial fibrillation (AF). XEN-D0101 inhibited Kv1.5 with an IC50 of 241 nM and is selective over non-target cardiac ion channels (IC50 Kv4.3, 4.2 μM; hERG, 13 μM; activated Nav1.5, >100 μM; inactivated Nav1.5, 34 μM; Kir3.1/3.4, 17 μM; Kir2.1, >>100 μM). In atrial myocytes from patients in sinus rhythm (SR) and chronic AF, XEN-D0101 inhibited non-inactivating outward currents (Ilate) with IC50 of 410 and 280 nM, respectively, and peak outward currents (Ipeak) with IC50 of 806 and 240 nM, respectively. Whereas Ilate is mainly composed of IKur, Ipeak consists of IKur and Ito. Therefore, the effects on Ito alone were estimated from a double-pulse protocol where IKur was inactivated (3.5 µM IC50 in SR and 1 µM in AF). Thus, inhibition of Ipeak is because of IKur reduction and not Ito. XEN-D0101 significantly prolonged the atrial action potential duration at 20%, 50%, and 90% of repolarization (AF tissue only) and significantly elevated the atrial action potential plateau phase and increased contractility (SR and AF tissues) while having no effect on human ventricular action potentials. In healthy volunteers, XEN-D0101 did not significantly increase baseline- and placebo-adjusted QTc up to a maximum oral dose of 300 mg. XEN-D0101 is a Kv1.5/IKur inhibitor with an attractive atrial-selective profile. |
13,365 | Differential effects of the peroxynitrite donor, SIN-1, on atrial and ventricular myocyte electrophysiology. | Oxidative stress has been implicated in the pathogenesis of heart failure and atrial fibrillation and can result in increased peroxynitrite production in the myocardium. Atrial and ventricular canine cardiac myocytes were superfused with 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1), a peroxynitrite donor, to evaluate the acute electrophysiologic effects of peroxynitrite. Perforated whole-cell patch clamp techniques were used to record action potentials. SIN-1 (200 µM) increased the action potential duration (APD) in atrial and ventricular myocytes; however, in the atria, APD prolongation was rate independent, whereas in the ventricle APD, prolongation was rate dependent. In addition to prolongation of the action potential, beat-to-beat variability of repolarization was significantly increased in ventricular but not in atrial myocytes. We examined the contribution of intracellular calcium cycling to the effects of SIN-1 by treating myocytes with the SERCA blocker, thapsigargin (5-10 µM). Inhibition of calcium cycling prevented APD prolongation in the atrial and ventricular myocytes, and prevented the SIN-1-induced increase in ventricular beat-to-beat APD variability. Collectively, these data demonstrate that peroxynitrite affects atrial and ventricular electrophysiology differentially. A detailed understanding of oxidative modulation of electrophysiology in specific chambers is critical to optimize therapeutic approaches for cardiac diseases. |
13,366 | Defibrillation waveform duration adjustment increases the proportion of acceptable defibrillation thresholds in patients implanted with single-coil defibrillation leads. | The aim of this study was to determine whether defibrillation waveform duration adjustment with single-coil defibrillation leads can be used to increase the proportion of patients with satisfactory defibrillation thresholds (DFTs). A retrospective analysis of the DFT levels for 105 patients with implantable cardioverter-defibrillator devices and a single-coil defibrillation lead was performed. Two groups of patients were compared: 34 patients who had undergone waveform tuning (group A) and 71 patients with a fixed-tilt waveform (group B). Additional data including demographics, etiology, New York Heart Association functional class, left ventricular ejection fraction, high-voltage lead impedance and medications were gathered to determine what effect these variables had on the DFT levels. Of the 34 patients who had undergone waveform adjustment (group A), 27 (79%) were found to have satisfactory DFTs, while 41 (58%) of the 71 patients with fixed-tilt devices (group B) had satisfactory DFTs. Waveform duration adjustment was found to significantly increase the proportion of patients with satisfactory DFTs (p = 0.03). |
13,367 | [Clinical and cardiac imaging characteristics of patients with left ventricular apical hypoplasia]. | To analyze the clinical and cardiac imaging characteristics of patients with left ventricular apical hypoplasia (LVAH).</AbstractText>From January 2008 to January 2012, seven patients [3 male/4 female, age: 6 - 44 (19.9 ± 14.2) years] with LVAH were included in this cohort. Transthoracic echocardiogram was performed in all patients, cardiovascular MRI was performed in 3 patients and cardiovascular CT in another 2 patients. In addition, one LVAH patient underwent cardiac catheterization and angiography examination.</AbstractText>Four out of 7 patients complained chest discomfort. Precordial murmur was heard in 3 patients. Atrial fibrillation was evidenced by electrocardiogram in 3 patients. Left ventricular end-diastolic diameter [(57.9 ± 11.6) mm] increased while left ventricule (LV) longitudinal diameter reduced in all patients. Left ventricular systolic function was reduced in 2 patients and mean LVEF was (47.6 ± 17.2)%. The interventricular septum bulged towards the right, and the ventricular septum thickness was (7.3 ± 1.2) mm. The papillary muscles were dominant on the flattened LV anteroapical region. The right ventricle elongated and wrapped around the hypoplastic left ventricular apex, and the dimension of right ventricle was (19.7 ± 7.6) mm. Focal fat replacement of the left ventricular apical wall was evidenced in 5 patients underwent cardiovascular MRI or CT examinations.</AbstractText>Clinical symptoms are non-specific in LVAH patients. Truncated and spherical LV, abnormal origin of papillary muscles in the flattened LV anterior apex and an elongated right ventricle wrapping around the LV apex as well as focal fat replacement of the left ventricular apical wall are typical imaging characteristics of LVAH.</AbstractText> |
13,368 | Expression of matrix metalloproteinases, their inhibitors, and lysyl oxidase in myocardial samples from dogs with end-stage systemic and cardiac diseases. | To compare the degree of mRNA expression for matrix metalloproteinases (MMPs), tissue inhibitors (TIMPs), and lysyl oxidase in myocardial samples from dogs with cardiac and systemic diseases and from healthy control dogs.</AbstractText>Myocardial samples from the atria, ventricles, and septum of 8 control dogs, 6 dogs with systemic diseases, 4 dogs with dilated cardiomyopathy (DCM), and 5 dogs with other cardiac diseases.</AbstractText>Degrees of mRNA expression for MMP-1, -2, -3, -9, and -13; TIMP-1, -2, -3, and -4; and lysyl oxidase were measured via quantitative real-time PCR assay. Histologic examination of the hearts was performed to identify pathological changes.</AbstractText>In myocardial samples from control dogs, only TIMP-3 and TIMP-4 mRNA expression was detected, with a significantly higher degree in male versus female dogs. In dogs with systemic and cardiac diseases, all investigated markers were expressed, with a significantly higher degree of mRNA expression than in control dogs. Furthermore, the degree of expression for MMP-2, TIMP-1, and TIMP-2 was significantly higher in dogs with DCM than in dogs with systemic diseases and cardiac diseases other than DCM. Expression was generally greater in atrial than in ventricular tissue for MMP-2, MMP-13, and lysyl oxidase in samples from dogs with atrial fibrillation.</AbstractText>Degrees of myocardial MMP, TIMP, and lysyl oxidase mRNA expression were higher in dogs with cardiac and systemic diseases than in healthy dogs, suggesting that expression of these markers is a nonspecific consequence of end-stage diseases. Selective differences in the expression of some markers may reflect specific pathogenic mechanisms and may play a role in disease progression, morbidity and mortality rates, and treatment response.</AbstractText> |
13,369 | Aborted sudden cardiac death due to radiofrequency ablation within the coronary sinus and subsequent total occlusion of the circumflex artery. | We report a case of aborted sudden cardiac death and subsequent development of malignant drug-refractory incessant ventricular tachycardia/fibrillation in a patient with acute coronary artery occlusion following radiofrequency ablation within the CS. Catheter ablation is a well-established therapy for treatment of atrial fibrillation (AF). In patients with longstanding persistent AF extensive left atrial ablation and ablation inside the coronary sinus (CS) is frequently performed. Perimitral flutter following AF ablation is the most common form of left atrial macroreentry, especially in patients with previous ablation of complex fractionated electrograms and incomplete linear lesion sets within the left atrium. Successful ablation of this type of tachycardia is generally difficult and in about 60-70% patients requires additional ablation within the CS to achieve termination of tachycardia or/and left atrial isthmus (LAI) block. A limited number of case reports have been published describing acute coronary artery occlusion during or immediately after LAI ablation within the CS. This case exhibits a potential lethal risk of radiofrequency ablation within the CS. |
13,370 | Clinical factors associated with left ventricular ejection fraction disparity in patients with left ventricular dysfunction undergoing multimodality imaging. | Drug and device therapy for heart failure is increasingly determined based on left ventricular ejection fraction. Significant disparity frequently exists between echocardiographic and nuclear scintigraphic techniques, even when testing is performed nearly simultaneously in clinically stable patients. In 119 patients with left ventricular dysfunction who underwent both echocardiography and stress testing with nuclear imaging within seven days (but with significant disparity in reported left ventricular ejection fraction), we identified four clinical variables which were associated with left ventricular ejection fraction difference. These clinical variables included atrial fibrillation, left ventricular hypertrophy, severe mitral regurgitation and paced rhythm. |
13,371 | Prehospital electrocardiographic manifestations of acute myocardial ischemia independently predict adverse hospital outcomes. | Prehospital electrocardiography (PH ECG) is becoming the standard of care for patients activating Emergency Medical Services for symptoms of acute coronary syndrome (ACS). Little is known about the prognostic value of ischemia found on PH ECG.</AbstractText>The purpose of this study was to determine whether manifestations of acute myocardial ischemia on PH ECG are predictive of adverse hospital outcomes.</AbstractText>This study was a retrospective analysis of all PH ECGs recorded in 630 patients who called 911 for symptoms of ACS and were enrolled in a prospective clinical trial. ST-segment monitoring software was added to the PH ECG device with automatic storage and transmission of ECGs to the destination Emergency Department. Patient medical records were reviewed for adverse hospital outcomes.</AbstractText>In 630 patients who called 911 for ACS symptoms, 270 (42.9%) had PH ECG evidence of ischemia. Overall, 37% of patients with PH ECG ischemia had adverse hospital outcomes compared with 27% of patients without PH ECG ischemia (p < 0.05). Those with PH ECG ischemia were 1.55 times more likely to have adverse hospital outcomes than those without PH ECG ischemia (95% CI 1.09-2.21; p < 0.05), after controlling for other predictors of adverse hospital outcomes (i.e., age, sex, and medical history).</AbstractText>Evidence of ischemia on PH ECG is an independent predictor of adverse hospital outcomes. ST-segment monitoring in the prehospital setting can identify high-risk patients with symptoms of ACS and provide important prognostic information at presentation to the Emergency Department.</AbstractText>Published by Elsevier Inc.</CopyrightInformation> |
13,372 | Susceptibility to ischemia-induced ventricular fibrillation in isolated female rat hearts varies moderately with estrous cycle stage. | The vast majority of studies employing the isolated perfused rat heart model to study ischemic arrhythmias have used male rats only. The objective of this study was to determine the susceptibility to ischemia-induced ventricular fibrillation (VF) in isolated female rat hearts in each stage of the estrous cycle that corresponds with a different endogenous reproductive hormonal environment.</AbstractText>Hearts were isolated from female rats under pentobarbital anesthesia and perfused with modified Krebs solution containing 3mM K(+). Experiments were grouped according to estrous cycle stage that was determined by prior vaginal lavage (n=10-13 per group). A group of male rat hearts was used as the control. Regional ischemia was induced by coronary ligation and maintained for 30min. The incidence of VF was determined from the ECG.</AbstractText>The incidence of VF in male hearts was 100%, while the incidence of VF in female hearts was also high but varied moderately with stage of the estrous cycle (diestrus 70%, metestrus 100%, proestrus 90%, estrus 69%; P>0.05). Compared to male hearts, the onset of VF was similar in all groups except for hearts excised from rats in proestrus, in which it was delayed. There was no difference between groups in an arrhythmia score, ischemic zone size, or baseline electrocardiographic or hemodynamic variables.</AbstractText>In conclusion, the susceptibility of isolated female rat hearts to ischemic VF is comparable to that of male rat hearts, meaning that isolated female rat hearts can be used as controls in studies to assess antiarrhythmic drug efficacy. Since female rats can be used for isolated heart studies of ischemic VF, the need to cull female rats is reduced. However, the variation in VF susceptibility in female rat hearts that is associated with the different stages of the estrous cycle may affect statistical power that could potentially lead to Type II statistical errors. This problem can be prevented with careful randomization.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,373 | Acute myocardial infarction as presentation of an infiltrative lung neoplasia. | We report the case of a 51-year-old woman who presented with acute myocardial infarction as initial symptom of an infiltrative lung neoplasia. The patient was admitted to our center following an out-of-hospital cardiac arrest due to ventricular fibrillation which was cardioverted. On electrocardiography an anterior wall ST-elevation was found and urgent coronary angiography was performed. Left anterior descending coronary artery was occluded and after thrombus aspiration, an image of diffuse loss of lumen diameter and absence of coronary branches was compatible with an extrinsic compression. Such findings along with a lingula consolidation on chest X-ray examination suggested a thoracic neoplasia. Enhanced-chest computed tomography showed a mass located in the lingula with extensive mediastinal infiltration involving pericardium and myocardium. Anatomopathologic examination confirmed the presence of lung adenocarcinoma. <<b>Learning objective:</b> In patients with neoplasms should be suspected cardiac tumor infiltration in those with acute myocardial infarction. Since differential diagnosis between true AMI electrocardiographic (ECG) changes and pseudo-AMI ECG changes in patients with secondary cardiac tumors assumed to be difficult, such TTE or IVUS findings of extra-cardiac tumor could help physicians to make an accurate diagnosis.>. |
13,374 | Defibrillation success with high frequency electric fields is related to degree and location of conduction block. | We recently demonstrated that high frequency alternating current (HFAC) electric fields can reversibly block propagation in the heart by inducing an oscillating, elevated transmembrane potential (Vm) that maintains myocytes in a refractory state for the field duration and can terminate arrhythmias, including ventricular fibrillation (VF).</AbstractText>To quantify and characterize conduction block (CB) induced by HFAC fields and to determine whether the degree of CB can be used to predict defibrillation success.</AbstractText>Optical mapping was performed in adult guinea pig hearts (n = 14), and simulations were performed in an anatomically accurate rabbit ventricular model. HFAC fields (50-500 Hz) were applied to the ventricles. A novel power spectrum metric of CB-the loss of spectral power in the 1-30 Hz range, termed loss of conduction power (LCP)-was assessed during the HFAC field and compared with defibrillation success and VF vulnerability.</AbstractText>LCP increased with field strength and decreased with frequency. Optical mapping experiments conducted on the epicardial surface showed that LCP and the size of CB regions were significantly correlated with VF initiation and termination. In simulations, subsurface myocardial LCP and CB sizes were more closely correlated with VF termination than surface values. Multilinear regression analysis of simulation results revealed that while CB on both the surface and the subsurface myocardium was predictive, subsurface myocardial CB was the better predictor of defibrillation success.</AbstractText>HFAC fields induce a field-dependent state of CB, and defibrillation success is related to the degree and location of the CB.</AbstractText>Copyright © 2013. Published by Elsevier Inc.</CopyrightInformation> |
13,375 | Routine preprocedural transesophageal echocardiography might not be necessary for stroke prevention evaluation in AF patients on anticoagulation therapy. | Preprocedural transesophageal echocardiography (TEE) is used to reduce the stroke during atrial fibrillation (AF) ablation. This study evaluated whether routine preprocedural TEE in addition to multidetector computed tomography (MDCT) is necessary to prevent periprocedural stroke in AF ablation.</AbstractText>Each patient underwent MDCT and TEE (group 1, n=247) or MDCT alone (group 2, n=103) for the initial evaluation before AF ablation. In group 2, TEE was performed only in patients who had left atrial (LA) thrombus or blood stasis in MDCT.</AbstractText>There was no difference in sex, CHADS2 score, or LA dimension between the two groups. In group 1, a thrombus was detected in 12 (5%) and 6 (2%) patients by the MDCT and TEE, respectively. All (100%) patients, who were revealed to have thrombus in TEE, also had a thrombus in MDCT. In group 2, 3 (3%) patients exhibited LA thrombus in MDCT, among whom thrombus was observed in only one patient (1%) in TEE. AF ablation was not performed in patients with thrombus. While one patient had a periprocedural stroke in group 1, no patient had in group 2 (P=0.52).</AbstractText>The overall periprocedural stroke rate was low (0.3%) in AF patients on anticoagulation therapy. The preprocedural MDCT detected all patients with the LA thrombus. In AF patients with low CHADS2 score, optimal anticoagulation and relatively preserved left ventricular ejection fraction, routine preprocedural TEE in addition to the MDCT might not be necessary to decrease the periprocedural stroke rate.</AbstractText>Copyright © 2012. Published by Elsevier Ireland Ltd.</CopyrightInformation> |
13,376 | Specific organized substrates of ventricular fibrillation: comparison of 320-slice CT heart images in non-ischemic ventricular fibrillation subjects with non-ischemic sustained and non-sustained ventricular tachycardia subjects. | If specific organized substrates of ventricular-fibrillation (VF) are identified, they may provide important-information for prevention of sudden-cardiac-death. To identify specific organized substrates of VF, we compared 320-slice CT heart images in non-ischemic VF subjects with non-ischemic sustained and non-sustained ventricular-tachycardia (VT) subjects.</AbstractText>Retrospective analysis of a total of 103 subjects who had VF (17 subjects; age, 59 ± 16 years), sustained VT (20 subjects; 62 ± 19 years), or non-sustained VT (66 subjects; 60 ± 15 years) underwent 320-slice CT (Aquilion one).</AbstractText>After excluding 26 ischemic subjects with >50% stenosis in any coronary arteries on CT, myocardial infarction, or coronary vasospastic angina, a total of 77 non-ischemic subjects (12 VF subjects; age, 58 ± 18 years), (13 sustained VT subjects; 55 ± 20 years) or (52 non-sustained VT subjects; 58 ± 15 years) were analyzed. On CT, myocardial abnormal-late-enhancement was significantly more frequent in the VF group (75%, all myocardial abnormal-late-enhancement in left-ventricle) than in the sustained VT group (31%) and the non-sustained VT group (35%) (both P<0.01). Myocardial fatty change was significantly more frequent in the sustained VT group (54%) than in the VF group (17%) and the non-sustained VT group (12%) (both P<0.01). Final diagnoses of the non-ischemic VF and sustained groups included four subjects in each case with normal cardiac structure on transthoracic echocardiogram; the former included two subjects who had abnormal-late-enhancement on CT without specific ECG findings.</AbstractText>Myocardial abnormal-late-enhancement and fatty change on CT may be substrates of VF or sustained VT in non-ischemic subjects. 320-slice CT can evaluate both coronary arteries and myocardium.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,377 | Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): an on-treatment analysis. | In the Ventricular Tachycardia Ablation in Coronary Heart Disease (VTACH) study, an intention-to-treat approach was used and may have diminished the observed degree of treatment effect. We present a subanalysis of the VTACH study by treatment actually received.</AbstractText>The VTACH study was a prospective, open, randomized controlled trial, undertaken in 16 European centers, comparing defibrillator implantation with and without ventricular tachycardia (VT) ablation in patients with stable VT, previous myocardial infarction, and reduced left-ventricular ejection fraction. Of the 52 patients in the ablation group, 7 (13%) did not receive VT ablation and 19% of patients assigned to implantable cardioverter defibrillator (ICD) only treatment group crossed over and had an ablation. The primary endpoint (first recurrence of any documented VT or ventricular fibrillation [VF]) was reached after a median of 19.5 months in the ablation group and 5.9 months in the ICD only group (P = 0.01). Overall, 685 VT/VF events occurred per year of follow-up in 22 patients of the ablation group and 4,986 events in 43 patients of the control group (P = 0.024). In the ICD only group, median numbers of VT/VF episodes were 25 (IQR 5.8-45.3) and 1.5 (IQR 0-24.8) per patient and year before and after crossover (n = 12), respectively.</AbstractText>On-treatment analysis of the VTACH study emphasizes the effectiveness of VT ablation in patients receiving ICD treatment because of monomorphic VT post myocardial infarction. VT ablation clearly prolonged time to recurrence of VT/VF episodes and markedly decreased VT/VF burden.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,378 | A KCNQ1 mutation causes a high penetrance for familial atrial fibrillation. | Atrial fibrillation (AF) is the most common cardiac arrhythmia, and its incidence is expected to grow. A genetic predisposition for AF has long been recognized, but its manifestation in these patients likely involves a combination of rare and common genetic variants. Identifying genetic variants that associate with a high penetrance for AF would represent a significant breakthrough for understanding the mechanisms that associate with disease.</AbstractText>Candidate gene sequencing in 5 unrelated families with familial AF identified the KCNQ1 missense mutation p.Arg231His (R231H). In addition to AF, several of the family members have abnormal QTc intervals, syncope or experienced sudden cardiac arrest or death. KCNQ1 encodes the voltage-gated K(+) channel that conducts the slowly activating delayed rectifier K(+) current in the heart. Functional and computational analyses suggested that R231H increases KCNQ1 current (I(KCNQ1)) to shorten the atrial action potential (AP) duration. R231H is predicted to minimally affect ventricular excitability, but it prevented the increase in I(KCNQ1) following PKA activation. The unique properties of R231H appeared to be caused by a loss in voltage-dependent gating.</AbstractText>The R231H variant causes a high penetrance for interfamilial early-onset AF. Our study indicates R231H likely shortens atrial refractoriness to promote a substrate for reentry. Additionally, R231H might cause abnormal ventricular repolarization by disrupting PKA activation of IKCNQ1 . We conclude genetic variants, which increase IKs during the atrial AP, decrease the atrial AP duration, and/or shorten atrial refractoriness, present a high risk for interfamilial AF.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,379 | Long-term prognostic value of restitution slope in patients with ischemic and dilated cardiomyopathies. | An action potential duration (APD) restitution curve with a steep slope ≥1 has been associated with increased susceptibility for malignant ventricular arrhythmias. We aimed to evaluate the "restitution hypothesis" and tested ventricular APD restitution slope as well as effective refractory period (ERP)/APD ratio for long-term prognostic value in patients with ischemic (ICM) or dilated cardiomyopathy (DCM).</AbstractText><AbstractText Label="METHODOLOGY/PRINCIPAL FINDINGS" NlmCategory="RESULTS">Monophasic action potentials were recorded in patients with ICM (n = 32) and DCM (n = 42) undergoing routine programmed ventricular stimulation (PVS). Left ventricular ejection fraction was 32±7% and 28±9%, respectively. APD and ERP were measured at baseline stimulation (S(1)) and upon introduction of one to three extrastimuli (S(2)-S(4)). ERP/APD ratios and the APD restitution curve were calculated and the maximum restitution slope was determined. After a mean follow-up of 6.1±3.0 years, the combined end-point of mortality and and/or implantable cardioverter-defibrillator shock was not predicted by restitution slope or ERP/APD ratios. Comparing S(2) vs. S(3) vs. S(4) extrastimuli for restitution slope (1.5±0.6 vs. 1.4±0.4 vs. 1.3±0.5; p = NS), additional extrastimuli did not lead to a steepening restitution slope. ERP/APD ratio decreased with additional extrastimuli (0.98±0.09 [S(1)] vs. 0.97±0.10 [S(2)] vs. 0.93±0.11 [S(3)]; p = 0.03 S(1) vs. S(3)). Positive PVS was strongly predictive of outcome (p = 0.006).</AbstractText><AbstractText Label="CONCLUSIONS/SIGNIFICANCE" NlmCategory="CONCLUSIONS">Neither ventricular APD restitution slope nor ERP/APD ratios predict outcome in patients with ICM or DCM.</AbstractText> |
13,380 | Osborn waves during therapeutic hypothermia in a young ST-ACS patient after out-of-hospital cardiac arrest. | A 37 year-old male patient was admitted to the intensive care unit after an out-of-hospital cardiac arrest due to ventricular fibrillation in a course of ST-segment elevation acute coronary syndrome. On admission, the patient was unconscious with a Glasgow Coma Scale (GCS) score of 5. A percutaneous coronary intervention and mild therapeutic hypothermia (HT), defined as maintaining body temperature between 32°C and 34°C, were performed. During HT on ECG, we observed Osborn waves, which resolved spontaneously after re-warming. After five days of recovery, the patient scored 15 on GCS and did not show any neurological deficits. |
13,381 | Catheter ablation of atrial fibrillation in patients with hypertrophic cardiomyopathy: atrial fibrillation type determines the success rate. | Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is generally associated with deterioration of the clinical status, functional capacity, and quality of life. It is also an independent risk factor for stroke and death. Studies evaluating the effectiveness of AF ablation in this cohort are relatively scant, have included relatively few patients, and their results are somewhat conflicting. Thus, the aim of this study was to assess the safety and efficacy of catheter ablation of AF in patients with HCM.</AbstractText>Thirty patients (10 females; mean age 48.7 ± 11 years) with drug-refractory paroxysmal (n = 14), persistent (n = 7), or long-persistent (> 1 year; n = 9) AF were prospectively recruited into the study. Eleven patients were in New York Heart Association (NYHA) class I, 13 patients were in NYHA class II, and 6 patients were in NYHA class III. Mean atrial volume was 180 ± 47 mL, interventricular septum thickness was 20.5 ± 6.3 mm, and left atrial area was 29.8 ± 6.2 cm2. Ablation protocol was adjusted to the clinical and electrophysiological status of the patients. Pulmonary vein isolation and bidirectional cavo-tricuspid isthmus block were performed in all patients. In addition, left atrial linear lesions were created and complex fragmented atrial potentials were ablated in patients with persistent and long-persistent AF, as well as during repeated procedures.</AbstractText>At 12 months, stable sinus rhythm (SR) was present in 16 (53%) patients, significantly more frequently in patients with paroxysmal AF (71% in SR) compared to those with persistent (57.1% in SR) or long-persistent (22% in SR) AF. A significant reduction of AF burden was observed in 85.7% of patients with paroxysmal AF, 71.4% of patients with persistent AF, and 55.5% of patients with long-persistent AF. Single procedure success rate was 33% (10 patients), and repeat ablation procedures were performed in 13 patients. No periprocedural complications occurred. Thromboembolic events were noted in 2 patients with arrhythmia recurrence during the follow-up, including stroke in 1 patient and peripheral embolism in the other patient. In both these patients, heart failure worsening was observed during these events, and anticoagulation was inadequate in one of them. Five of 16 patients in whom stable SR was observed during the follow-up were off antiarrhythmic drug therapy at final evaluation. In the other 6 patients, antiarrhythmic drug therapy was continued due to ventricular arrhythmias. Successfully treated patients more often had paroxysmal AF (successful ablation: paroxysmal AF in 10 of 16 patients; unsuccessful ablation: paroxysmal AF in 4 of 14 patients; p = 0.009) and were younger (45 ± 11.5 years vs. 52.6 ± 9.2 years; p = 0.046). In addition, a trend toward a reduced need for cardioversion at the end of the procedure was also observed in these patients (3 patients in the successful ablation group vs. 8 patients in the unsuccessful ablation group; p = 0.056). In multivariate regression analysis, paroxysmal AF was the only independent predictor of a successful outcome.</AbstractText>Catheter ablation of AF in patients with HCM is an effective and safe therapeutic option, particularly in patients with paroxysmal AF. Effectiveness of ablation is significantly smaller in patients with persistent AF and even more so in those with long-persistent AF. Repeated procedures were often necessary. Continued antiarrhythmic drug therapy is often required due to a significant degree of atrial remodelling.</AbstractText> |
13,382 | Unusual case of severe arrhythmia developed after acute intoxication with tosylchloramide. | Drugs not commonly considered to be cardioactive agents may cause prolongation of the QT interval with resultant torsades de pointes and ventricular fibrillation. This form of drug toxicity often causes cardiac arrest or sudden death.</AbstractText>After accidental ingestion of tosylchloramide a caucasian 77-year-old woman, with a family history of cardiovascular disease and hypertension, was admitted to the intensive care unit following episodes of torsades de pointes with a prolonged QT/QTc interval (640/542 ms). The patient received an implantable cardioverter-defibrillator, was discharged from the hospital with normal QT/QTc interval and did not experience additional ventricular arrhythmias during one year of follow-up.</AbstractText>This is the first report concerning an unusual case of torsades de pointes after accidental intoxication by ingestion of tosylchloramide. The pronounced impact of the oxidyzing agent tosylchloramide on the activity of some of the ion channels regulating the QT interval was identified as a probable cause of the arrhythmia.</AbstractText> |
13,383 | Ventricular extrasystoles with interpolation or postponed compensatory pause during atrial fibrillation: fact or fiction? | A Holter recording obtained from a patient with atrial fibrillation showed ventricular extrasystoles often in bigeminal rhythm. Most extrasystoles were followed by a long return cycle, and only in a few instances the postextrasystolic interval was short. The latter phenomenon was interpreted as a manifestation of poor retrograde concealed penetration of the ventricular impulse into the atrioventricular (A-V) junction: accordingly, an ensuing relatively early fibrillation impulse reached the ventricular chamber, since it did not find the A-V node refractory. These events are similar to what happens in interpolated ventricular extrasystoles occurring during sinus rhythm, the absent or minimal concealed retrograde penetration of the ectopic impulse into the A-V node being necessary to permit anterograde conduction of the ensuing sinus impulse. Analysis of the recording also revealed that a very long (>2 second) interval between two consecutive narrow beats only occurred after an "interpolated" extrasystole. This was interpreted with the same mechanism underlying the "postponed compensatory pause" observed at times after interpolated ventricular extrasystoles during sinus rhythm: the minimal or nil penetration of the ventricular ectopic impulse into the A-V junction, followed by conduction of an ensuing early atrial impulse, "shifts to the right" the A-V nodal refractory period, preventing conduction of several further supraventricular impulses and generating a pause. Both interpolated ventricular extrasystoles and the phenomenon of "postponed compensatory pause" are, thus, conceivable during atrial fibrillation, although no definite demonstration is possible. |
13,384 | Association between atrial fibrillatory rate and heart rate variability in patients with atrial fibrillation and congestive heart failure. | Even if atrial fibrillatory rate (AFR) has been related to clinical outcome in patients with atrial fibrillation (AF), its relation with ventricular response has not been deeply studied. The aim of this study was to investigate the relation between AFR and RR series variability in patients with AF.</AbstractText>Twenty-minute electrocardiograms in orthogonal leads were processed to extract AFR, using spatiotemporal QRST cancellation and time frequency analysis, and RR series in 127 patients (age 69 ± 11 years) with congestive heart failure (NYHA II-III) enrolled in the MUSIC study (MUerte Subita en Insufficiencia Cardiaca). Heart rate variability and irregularity were assessed by time domain parameters and entropy-based indices, respectively and their correlation with AFR investigated.</AbstractText>Variability measures seem not to be related to AFR, while irregularity measures do. A significant correlation between AFR and variability parameters of heart rate variability during AF was found only in patients not treated with antiarrhythmics drugs (correlation = 0.56 P < 0.05 for pNN50), while this correlation was lost in patients taking rate- or rhythm-control drugs. A significant positive correlation between AFR and indices of RR irregularity was found, showing that a higher AFR is related to a less organized RR series (correlation = 0.33 P < 0.05 for regularity index for all patients, correlation increased in subgroups of patients treated with the same drug).</AbstractText>These results suggest that a higher AFR is associated with a higher degree of irregularity of ventricular response that is observed regardless of the use of rate-controlling drugs.</AbstractText>©2012, Wiley Periodicals, Inc.</CopyrightInformation> |
13,385 | Surgical timing of degenerative mitral regurgitation: what to consider. | Severe primary mitral regurgitation (MR) is a progressive condition which engenders significant mortality and morbidity if left untreated. The optimal timing of surgery in patients with MR of degenerative origin continues to be debated, especially for those who are asymptomatic. Apart from symptoms, current authoritative guidelines recommend intervention when there is incipient left ventricular dysfunction, pulmonary hypertension or new onset atrial fibrillation. This review focuses on the asymptomatic subject with severe MR, and examines contemporary clinical decision-making and management strategies, including the 2012 European guidelines on valvular heart disease. We discuss the rationale for risk stratifying the asymptomatic individual, and highlight current and novel diagnostic tools that may have a useful role, with an emphasis on echocardiographic imaging. |
13,386 | Management of moderate secondary mitral regurgitation at the time of aortic valve surgery. | To define the impact of surgical strategy [concomitant mitral valve surgery or isolated aortic valve replacement (AVR)] in patients with moderate secondary mitral regurgitation (MR) at the time of AVR.</AbstractText>From January 1999 to December 2009, 3339 patients underwent AVR of whom 255 had secondary MR >2+ and constituted the study population. Patients were stratified into two groups, with (Group A, n = 94, 36.8%) and without concomitant mitral valve surgery (Group B, n = 161, 63.2%). Follow-up up to 12 years (1076 patient-years) was analysed for survival, valve-related events and persistent MR. Predictors of late mortality and persistent MR were further analysed. A case-match analysis [age, gender, New York Heart Association (NYHA) and left ventricular ejection fraction] was performed, excluding patients with coronary artery disease (CAD).</AbstractText>The mean age of the population was 67.0 ± 11.7 years, 63.5% male and 64.7% in NYHA III-IV. Group B patients were significantly older and had higher incidence of coronary disease, hypertension and mitral calcification. They also had a higher ejection fraction and transaortic gradients, and lower MR grade (mean MR: 2.8 vs 3.2) and pulmonary artery pressure. Mitral surgery consisted mainly of annuloplasty procedures (96%). Only 2 patients from the entire cohort were reoperated on/for the mitral valve. Thirty-day mortality rate was 0.3%. There was no difference in long-term survival and valve-related complications, even after case-matched analysis. CAD, history of cerebrovascular accident, permanent atrial fibrillation, renal failure and persistence of MR emerged as independent predictors of late mortality (P < 0.05). MR improved in 67.4% of patients from Group B against 82.3% from Group A (P = 0.011). Atrial fibrillation (AF) and higher MR grade at discharge were the only independent predictors for persistent MR (P < 0.05). Patients with persistent MR early after AVR had decreased late survival (hazard ratio: 4.9, P = 0.001).</AbstractText>Secondary MR improves after AVR even without mitral surgery. Concomitant mitral surgery was significantly associated with greater improvement of postoperative MR, but had no significant impact on survival. However, patients who did not improve immediately after AVR had compromised survival. Patients in AF should have mitral valve repair at the time of surgery.</AbstractText> |
13,387 | Utility of NT-proBNP for identifying LV failure in patients with acute exacerbation of chronic bronchitis. | NT-proBNP has been widely regarded as a useful tool for diagnosis or exclusion of heart failure (HF) in many settings. However, in patients with acute exacerbation of chronic bronchitis (AECB), its roles have not been well described. The objective of this study was to evaluate the diagnostic performance of NT-proBNP for identifying left ventricular (LV) failure in such patients.</AbstractText>311 AECB patients and 102 stable chronic bronchitis patients with no history of HF were enrolled. Plasma NT-proBNP concentrations were measured using Roche Elecsys. The European Society of Cardiology (ESC) diagnostic principles were adopted to identify HF and the diagnostic performance of NT-proBNP was evaluated by ROC. Our results showed, the median NT-proBNP level in patients with LV failure [4828.4 (2044.4-9203.6) ng/L] was significantly higher than that in those without LV failure [519.2 (179.1-1409.8) ng/L, p<0.001] and stable controls [207.5 (186.5-318.2) ng/L, p<0.001]. LV failure, renal function, atrial fibrillation and systolic pulmonary artery pressure were independent predictors of NT-proBNP levels (all p<0.05). The area under ROC curve (AUC) of NT-proBNP for identifying LV failure was 0.884, significantly superior to clinical judgment alone (AUC 0.835, p = 0.0294). At the optimal cutoff value of 935.0 ng/L, NT-proBNP yielded sensitivity 94.4%, specificity 68.2%, accuracy 74.3% and negative predictive value 97.6%. Adding the results of NT-proBNP to those of clinical judgment improved the diagnostic accuracy for LV failure.</AbstractText>As a tool for diagnosis or exclusion of HF, NT-proBNP can help physicians identify LV failure in patients with AECB.</AbstractText> |
13,388 | Atrial selectivity in Na+channel blockade by acute amiodarone. | Na(+) channel blockers are often used to treat atrial fibrillation (AF), but may sometimes cause ventricular contractile dysfunction. However, amiodarone, a multi-channel blocker with Na(+) channel block, causes less contractile dysfunction. In this study, we tested the hypothesis that Na(+) channel block by amiodarone is selective in atrial myocytes (AM) compared with ventricular myocytes (VM).</AbstractText>Na(+) currents (INa) were measured using whole-cell patch-clamp technique in isolated rabbit AM and VM. Amiodarone inhibited INa in AM (IC50: 1.8 ± 1.1 μM; n = 8) much more than in VM (40.4 ± 11.9 μM; n = 7, P < 0.01). Amiodarone at 10 μM shifted the steady-state inactivation relationship in AM (-16.2 ± 1.7 mV shift, n = 12) compared with VM (-5.9 ± 0.7 mV shift; n = 13; P < 0.01). For mexiletine, the inhibition of INa and inactivation curve shifts were comparable for AM and VM. The effects of amiodarone and mexiletine on conduction velocity (CV) in Langendorff-perfused rabbit hearts were evaluated using an optical mapping system. The decrease of CV by 3 μM amiodarone was significantly larger in the atrium (-18.9 ± 3.8% change; n = 5) compared with the ventricle (-3.7 ± 3.7%; n = 5; P < 0.01). In contrast, mexiletine reduced CV equally in the atrium and the ventricle.</AbstractText>Amiodarone preferentially inhibits INa of AM compared with VM. Atrial selective Na(+) channel block by amiodarone may contribute to treating AF with less effect on ventricular contractility than other Na(+) channel blockers.</AbstractText> |
13,389 | Magnetic resonance imaging in clinical cardiac electrophysiology. | Radiofrequency ablation is routinely used to treat numerous cardiac arrhythmias originating in the atrium and the ventricle. The process of ablation was pioneered to treat supraventricular tachycardias originating from fixed electrical circuits. These circuits could be identified using innovative electrophysiological maneuvers, which have been refined over the years to achieve excellent cure rates using fluoroscopy. More recently, electrophysiology ablation procedures have been greatly expanded to treat more diffuse arrhythmias like atrial fibrillation and ventricular tachycardia that are sustained by a remodeled myocardium or scar tissue. Given that there is no fixed circuit to target during most of these ablations, especially atrial fibrillation, there is a need to better visualize the substrate or the remodeling in the myocardium. Currently, when ablating atrial fibrillation or ventricular tachycardias, it is routine to use a cardiac CT or intra-cardiac echocardiogram to provide a three-dimensional anatomical structural map of the heart. This approach does not provide any substrate information like fibrosis or scar tissue in the myocardium. MRI has excellent soft-tissue visualization characteristics and has been used extensively to characterize the myocardial tissue as scar or fibrosis. This structural remodeling information of the myocardium is increasingly being used, along with the three-dimensional structural information in the ablation procedures, with the goal of improving the outcome. In addition MRI can also be used to visualize radiofrequency ablation lesions, potentially leading to significant improvement in procedural outcomes. |
13,390 | Evaluation of patients with cardiac amyloidosis using echocardiography, ECG and right heart catheterization. | To characterize patients with cardiac amyloidosis using echocardiography, electrocardiogram (ECG) and right heart catheterization (RHC).</AbstractText>Fourteen patients with biopsy verified light chain or transthyretin cardiac amyloidosis were included. All patients had heart failure with markedly elevated NT-proBNP. Echocardiography demonstrated biventricular hypertrophy, left atrial enlargement and normal to slightly reduced left ventricular ejection fraction. Tissue Doppler septal é was low and median E/é was high. Within 6 months RHC was performed in eight of the patients. The restrictive filling pattern demonstrated by echocardiography corresponded well to median pulmonary wedge pressure (21 mmHg). Systolic pulmonary artery pressure (SPAP) was increased, whereas cardiac output and stroke volume were seen to be decreased with both methods. ECG demonstrated: low voltage (36%), abnormal R-progression (65%), ST-T abnormalities (71%) and high incidence of fibrillation (36%). In addition, a case report following the treatment of melphalan and dexamethasone is presented with improvement of hypertrophy, SPAP, left ventricular mass and é.</AbstractText>These findings should lead to a suspicion of cardiac amyloidosis and suggest further investigation.</AbstractText> |
13,391 | Catheter ablation of ventricular fibrillation storm in a long QT syndrome genotype carrier with normal QT interval. | Patients with long QT syndrome can sometimes present with a ventricular fibrillation (VF) storm. Catheter ablation of culprit premature ventricular complexes responsible for the triggering of the VF episodes may be required in rare cases of electrical storm that do not respond to conventional measures, and this can be life-saving. We describe a case of emergency catheter ablation in a young woman with a normal corrected QT interval, who presented with malignant VF storm for the first time. We also discuss the diagnostic and management challenges involved, as well as the value of genetic testing in refining the diagnosis. |
13,392 | Early detection of ischemia by implantable cardioverter defibrillator capable of intracardiac electrogram monitoring in a case of old myocardial infarction. | A 72-year-old man received an implantation of implantable cardioverter defibrillator with intracardiac electrogram (ICEG) monitoring because ventricular fibrillation occurred in a case of old myocardial infarction with reduced left ventricular function. A year later, he came to our hospital for a regular checkup. Unexpectedly, ST depression was recorded by ICEG monitoring. He had no significant symptoms at the time, but had had exertional chest discomfort about 3 or 4 weeks before. The patient subsequently underwent successful revascularization, which potentially prevented the recurrence of acute myocardial infarction. ST depression has not been recorded by ICEG monitoring since the revascularization. |
13,393 | [Magnetic resonance imaging of dilated cardiomyopathy]. | Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy with a prevalence of 1 out of 2,500 in adults. Due to mild clinical symptoms in the early phase of the disease, the true prevalence is probably even much higher. Patients present with variable clinical symptoms ranging from mild systolic impairment of left ventricular function to congestive heart failure. Even sudden cardiac death may be the first clinical symptom of DCM. The severity of the disease is defined by the degree of impairment of global left ventricular function. Arrhythmias, such as ventricular or supraventricular tachycardia, atrioventricular (AV) block, ventricular extrasystole and atrial fibrillation are common cardiac manifestations of DCM. Magnetic resonance imaging (MRI) plays an important role in the exact quantification of functional impairment of both ventricles and in the evaluation of regional wall motion abnormalities. With its excellent ability for the assessment of myocardial structure, it is becoming increasingly more important for risk stratification and therapy guidance. |
13,394 | Clinical significance of the assessment of the systolic and diastolic myocardial function of the left atrium in patients with paroxysmal atrial fibrillation and low CHADS(2) index treated with catheter ablation therapy. | The purpose of this study was to determine the clinical significance of the assessment of the diastolic and systolic myocardial function of the left atrium in patients with paroxysmal atrial fibrillation (AF) and low CHADS(2) scores treated with catheter ablation therapy. In a cohort of 84 symptomatic patients with paroxysmal AF and low CHADS(2) scores (≤1), the clinical significance of the systolic and diastolic myocardial function of the left atrium (assessed using 2-dimensional speckle-tracking echocardiography) were studied to predict the risk for recurrence of AF after catheter ablation therapy in the course of a follow-up period of ≥1 year. During a mean follow-up period of 19.2 ± 5.4 months, patients with left atrial (LA) myocardial diastolic dysfunction (LA strain <18.8%) had a significantly higher rate of recurrence of AF (42.4% vs 9.8%, p <0.05) compared to those without LA diastolic dysfunction. In line with this finding, patients with impaired LA myocardial systolic function (LA strain rate >-0.85 s(-1)) had worse outcomes after catheter ablation therapy than those with normal LA systolic function (rate of recurrence of AF 42.9% vs 12.5%, respectively, p <0.05). In relation to these results, in a logistic regression analysis including co-morbidities, left ventricular dysfunction, LA enlargement, and LA myocardial alterations, diastolic and systolic LA myocardial dysfunction were the principal variable associated with the recurrence of AF (odds ratios 6.8 and 5.2, respectively). In conclusion, in symptomatic patients with paroxysmal AF and low CHADS(2) scores, these findings suggest that the assessment of diastolic and systolic LA myocardial function using 2-dimensional speckle-tracking echocardiography could be of great utility to distinguish those patients with high or low risk for recurrence of AF after catheter ablation therapy. |
13,395 | Impact of shock energy and ventricular rhythm on the success of first shock therapy: the ALTITUDE first shock study. | The efficacy of shock in converting different ventricular tachyarrhythmias has not been well characterized in a large natural-practice setting.</AbstractText>To determine shock success rate by energy and ventricular rhythm in a large cohort of patients with implantable cardioverter-defibrillators.</AbstractText>Two thousand patients with 5279 shock episodes were randomly sampled for analysis from the LATITUDE remote monitoring system. Within an episode, the rhythm preceding therapy (shock or antitachycardia pacing [ATP]) was adjudicated. Patients who died after unsuccessful implantable cardioverter-defibrillator shocks did not transmit final remote monitoring data and were not included in the study.</AbstractText>Of 3677 shock episodes for ventricular tachyarrhythmia, 2679 were treated with shock initially and were classified as monomorphic ventricular tachycardia ( n = 1544), polymorphic/monomorphic ventricular tachycardia (n = 371), or ventricular fibrillation (n = 764). The success rate after the first, second, and final shock averaged 90.3%, 96.4%, and 99.8%, respectively. After unsuccessful initial ATP (n = 998), the first, second, and final shock was successful in 84.8%, 92.9%, and 100% of the episodes. The success rate after the first or second shock was significantly lower after failed ATP compared to shock as first therapy (both P<.001). Among episodes treated initially with shock, the success rate for monomorphic ventricular tachycardia (89.2%) when treated with energy level ≤ 20 J was significantly higher than that for ventricular fibrillation (80.8%) (P = .04). The level of shock energy was a significant predictor of the success of the first shock (odds ratio 1.16; 95% confidence interval 1.03-1.30; P = .013).</AbstractText>The success rate of first shock as first therapy is approximately 90%, but was lower after failed ATP. Programming a higher level of energy after ATP is suggested.</AbstractText>Copyright © 2013. Published by Elsevier Inc.</CopyrightInformation> |
13,396 | A new biomarker--index of cardiac electrophysiological balance (iCEB)--plays an important role in drug-induced cardiac arrhythmias: beyond QT-prolongation and Torsades de Pointes (TdPs). | In the present study, we investigated whether a new biomarker - index of cardiac electrophysiological balance (iCEB=QT/QRS) - could predict drug-induced cardiac arrhythmias (CAs), including ventricular tachycardia/ventricular fibrillation (VT/VF) and Torsades de Pointes (TdPs).</AbstractText>The rabbit left ventricular arterially-perfused-wedge was used to investigate whether the simple iCEB measured from the ECG is reflective of the more difficult measurement of λ (effective refractory period×conduction velocity) for predicting CAs induced by a number of drugs.</AbstractText>Dofetilide concentration-dependently increased iCEB and λ, predicting potential risk of drug-induced incidence of early afterdepolarizations (EADs) starting at 0.01μM. Digoxin (1 and 5μM), encainide (5 and 20μM) and propoxyphene (10 and 100μM) markedly reduced both iCEB and λ, predicting their ability to induce non-TdP-like VT/VF. At 10μM, both NS1643 and levcromakalim significantly decreased λ and iCEB, which was preceded with presence of non-TdP-like VT/VF. Isoprenaline (0.05 to 0.5μM) significantly reduced both λ and iCEB, which was associated with a high incidence of non-TdP-like VT/VF in most preparations. Other biomarkers (i.e. transmural dispersion of T-wave and instability of the QT interval) predicted only dofetilide-induced long QT and EADs, but did not predict drug-induced risk of non-TdP-like VT/VF.</AbstractText>Our data from 7 reference drugs of known pro-arrhythmic effects suggests that 1) this non-invasive iCEB predicts potential risk of drug-induced CAs beyond long QT and TdP; 2) iCEB is more useful than the current biomarkers (i.e. transmural dispersion and instability) in predicting potential risks for drug-induced non-TdP-like VT/VF.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,397 | [Mortality of interventricular septum rupture after acute myocardial infarction with surgical management]. | ventricular septal rupture is a rare complication of myocardial infarction. It is considered the most serious mechanical disturbance in these cases. The mortality of patients during the hospital period receiving surgical treatment for this complication is described.</AbstractText>a case series study, including patients with ventricular septal rupture posterior to myocardial infarction, detected with a retrospective review of records of patients subjected to surgical repair from December 2005 to December 2010.</AbstractText>a total of 20 patients were included, with an average age of 56 years (48-65 years), male gender in 16 cases (80%), and a male: female relation of 4:1. Ten (50%) of the patients died; five due to multiple organ failure, one from nosocomial pneumonia, two from ventricular fibrillation, and two from refractory shock secondary to biventricular failure during the surgery. The factors identified for poor prognosis were the average time of 145 minutes on cardiopulmonary bypass, and acute kidney injury in six cases, requiring replacement therapy.</AbstractText>ventricular septal rupture is a rare complication with a high mortality. Without surgical treatment mortality can reach almost 100%. The mortality of this pathology treated with surgical closing in our hospital was 50%, similar to other published reports. Our findings confirm that although surgery for ventricular septal rupture has a high mortality it should be carried out because it is a surgical emergency.</AbstractText> |
13,398 | Echocardiographic parameters to predict inadequate defibrillation safety margin in patients receiving implantable cardioverter defibrillators for primary prevention. | Implantable cardioverter defibrillators (ICDs) have become an important part of the management of patients with congestive heart failure. At the time of ICD implantation, ventricular fibrillation (VF) is induced to assess adequate energy required for defibrillation. There are multiple parameters which influence the defibrillation safety margin (DSM); however, these factors are not well-established when ICDs are implanted for the primary prevention of sudden cardiac death (SCD) in patients with severe systolic dysfunction. We evaluated multiple clinical and echocardiographic parameters as predictors of adequate DSM in patients referred for ICD implantation for the primary prevention of SCD.</AbstractText>We prospectively enrolled 41 patients for ICD implantation with clinical indications for the primary prevention of SCD. Two blinded independent readers evaluated the prespecified echocardiographic parameters. These included left ventricular (LV) mass, indices of right ventricular and LV systolic and diastolic functions, and LV geometric dimensions. Basic clinical demographics, including age, gender, comorbidities, and etiology of cardiomyopathy, were also evaluated. DSM was established using our standard protocol for defibrillation testing which includes VF with successful first shock terminating VF at a value at least 10 J below the maximum output of the implanted device. High defibrillation thresholds (DFT) were defined as >21 J.</AbstractText>The mean age is 61.8 ± 14.7 years, with men comprising the majority of the patients (73 %). The only clinical variables which predicted the high DFT were age (in years) (54.5 ± 17.5 vs. 65.7 ± 11.3, p = 0.044), QRS duration (in milliseconds) (116.0 ± 29.5 vs. 110.5 ± 21.8, p = 0.03), LV mass (in grams) (241.0 ± 77.9 vs. 181.9 ± 52.3, p = 0.006), and LV mass index (in grams per square meter) (111.1 ± 38.2 vs. 86.4 ± 21.1, p = 0.02). On multivariate logistic regression analysis, LV mass was the only independent predictor of low DFT (≤22 J) in patients with ICD implanted for the primary prevention of SCD.</AbstractText>LV mass may help predict an adequate DSM in patients who are referred for ICD implantation for the primary prevention of SCD. These results may help distinguish the patients who may require high-energy devices prior to the implantation procedure. These results may help distinguish patients requiring high-energy devices, coils, or advanced programming prior to implantation and appropriate referral to electrophysiologists.</AbstractText> |
13,399 | "GIOSAT": a tool to assess CanMEDS competencies during simulated crises. | Our objective was to develop and evaluate a Generic Integrated Objective Structured Assessment Tool (GIOSAT) to integrate Medical Expert and intrinsic (non-medical expert) CanMEDS competencies with non-technical skills for crisis simulation.</AbstractText>An assessment tool was designed and piloted using two pediatric anesthesia scenarios (laryngospasm and hyperkalemia). Following revision of the tool, we used previously recorded videos of anesthesia residents (n = 50) who managed one of two intraoperative advanced cardiac life support (ACLS) scenarios (ventricular tachycardia or ventricular fibrillation). Four independent trained raters, blinded to the residents' level of training, analyzed the video recordings using the GIOSAT scale. Inter-rater reliability was calculated using intraclass correlations (ICCs) for single raters (single measure) and the average of the four raters (average measure), and construct validity was investigated by correlating GIOSAT scores with postgraduate year of residency (PGY).</AbstractText>Total GIOSAT scores for the ACLS scenarios had single measure ICCs of 0.62 and average measure ICCs of 0.85. Inter-rater reliability was substantial for both Medical Expert and intrinsic competencies (single measure ICCs 0.69 and 0.62, respectively; average measure ICCs 0.90 and 0.82, respectively). We found significant correlations between PGY level and total GIOSAT score (r = 0.36; P = 0.011) and between PGY level and Medical Expert competencies (r = 0.42; P = 0.003); however, correlations were not found between PGY level and intrinsic CanMEDS competencies (r = 0.24; P = 0.09).</AbstractText>Inter-rater reliability of the total GIOSAT scores using four trained raters was substantial. Significant correlation between PGY and (i) total GIOSAT score and (ii) Medical Expert competencies supports construct validity. Evidence of validity was not obtained for intrinsic CanMEDS competencies.</AbstractText> |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.