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15,500 | Atrial fibrillation as the initial clinical manifestation of cardiac sarcoidosis: a case report and review of the literature. | Cardiac sarcoidosis is an unusually rare form of sarcoidosis that often remains silent clinically; although if not screened for and diagnosed early can lead to disastrous consequences, which include sudden death. In addition to sudden death, cardiac sarcoidosis can present with myriad manifestations, including congestive heart failure and conduction blocks, as well as atrial or ventricular arrhythmias. We hereby present a case report of 45-year-old African-American male who repeatedly presented in the emergency room with episodes of paroxysomal supraventricular tachycardia (PSVT) as well as atrial fibrillation of unknown origin. Detailed workup led to a successful diagnosis of cardiac sarcoidosis, which is being treated with 1 mg/kg of steroids daily. Our focus on this report is that with recent advances in imaging technology, cardiac sarcoidosis can be detected more easily than before. Therefore, a high degree of clinical suspicion and systematic evaluation to uncover the cardiac involvement is warranted to improve outcomes of patients with sarcoidosis and cardiac involvement. |
15,501 | Defibrillation threshold testing fails to show clinical benefit during long-term follow-up of patients undergoing cardiac resynchronization therapy defibrillator implantation. | The utility of defibrillation threshold testing in patients undergoing implantable cardioverter-defibrillator (ICD) implantation is controversial. Higher defibrillation thresholds have been noted in patients undergoing implantation of cardiac resynchronization therapy defibrillators (CRT-D). Since the risks and potential benefits of testing may be higher in this population, we sought to assess the impact of defibrillation safety margin or vulnerability safety margin testing in CRT-D recipients.</AbstractText>A total of 256 consecutive subjects who underwent CRT-D implantation between January 2003 and December 2007 were retrospectively reviewed. Subjects were divided into two groups based on whether (n= 204) or not (n= 52) safety margin testing was performed. Patient characteristics, tachyarrhythmia therapies, procedural results, and clinical outcomes were recorded. Baseline characteristics, including heart failure (HF) severity, were comparable between the groups. Four cases of HF exacerbation (2%), including one leading to one death, were recorded in the tested group immediately post-implantation. No complications were observed in the untested group. After a mean follow-up of 32 ± 20 months, the proportion of appropriate shocks in the two groups was similar (31 vs. 25%, P = 0.49). There were three cases of failed appropriate shocks in the tested group, despite adequate safety margins at implantation, whereas no failed shocks were noted in the untested group. Survival was similar in the two groups.</AbstractText>Defibrillation efficacy testing during implant of CRT-D was associated with increased morbidity and did not predict the success of future device therapy or improve survival during long-term follow-up.</AbstractText> |
15,502 | Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial. | Active compression-decompression cardiopulmonary resuscitation (CPR) with decreased intrathoracic pressure in the decompression phase can lead to improved haemodynamics compared with standard CPR. We aimed to assess effectiveness and safety of this intervention on survival with favourable neurological function after out-of-hospital cardiac arrest.</AbstractText>In our randomised trial of 46 emergency medical service agencies (serving 2·3 million people) in urban, suburban, and rural areas of the USA, we assessed outcomes for patients with out-of-hospital cardiac arrest according to Utstein guidelines. We provisionally enrolled patients to receive standard CPR or active compression-decompression CPR with augmented negative intrathoracic pressure (via an impedance-threshold device) with a computer-generated block randomisation weekly schedule in a one-to-one ratio. Adults (presumed age or age ≥18 years) who had a non-traumatic arrest of presumed cardiac cause and met initial and final selection criteria received designated CPR and were included in the final analyses. The primary endpoint was survival to hospital discharge with favourable neurological function (modified Rankin scale score of ≤3). All investigators apart from initial rescuers were masked to treatment group assignment. This trial is registered with ClinicalTrials.gov, number NCT00189423.</AbstractText>2470 provisionally enrolled patients were randomly allocated to treatment groups. 813 (68%) of 1201 patients assigned to the standard CPR group (controls) and 840 (66%) of 1269 assigned to intervention CPR received designated CPR and were included in the final analyses. 47 (6%) of 813 controls survived to hospital discharge with favourable neurological function compared with 75 (9%) of 840 patients in the intervention group (odds ratio 1·58, 95% CI 1·07-2·36; p=0·019]. 74 (9%) of 840 patients survived to 1 year in the intervention group compared with 48 (6%) of 813 controls (p=0·03), with equivalent cognitive skills, disability ratings, and emotional-psychological statuses in both groups. The overall major adverse event rate did not differ between groups, but more patients had pulmonary oedema in the intervention group (94 [11%] of 840) than did controls (62 [7%] of 813; p=0·015).</AbstractText>On the basis of our findings showing increased effectiveness and generalisability of the study intervention, active compression-decompression CPR with augmentation of negative intrathoracic pressure should be considered as an alternative to standard CPR to increase long-term survival after cardiac arrest.</AbstractText>US National Institutes of Health grant R44-HL065851-03, Advanced Circulatory Systems.</AbstractText>Copyright © 2011 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
15,503 | Successful therapeutic hypothermia in patients with congenital long QT syndrome. | Therapeutic hypothermia has been shown to improve neurological outcomes in patients who remain comatose following resuscitation from cardiac arrest. While there are numerous reports of patients who have had a successful course after induction of therapeutic hypothermia, such therapeutic intervention has not been described in patients with congenital long QT syndrome (LQTS). We report outcomes in two patients with LQTS who had therapeutic hypothermia following a ventricular fibrillation arrest. Careful and routine monitoring of the QT interval in this patient population is necessary due to the potential for worsening electrical instability during induced hypothermia. |
15,504 | Ventricular fibrillation following successful DC cardioversion for atrial fibrillation. | Cardioversion remains an important therapy in the management of atrial fibrillation. Here, we report a case where direct current cardioversion resulted in a sudden dramatic change of heart rate that was associated with multiple ventricular fibrillation arrests in a manner akin to that previously observed post-atrioventricular node ablation. |
15,505 | Predictive value of B-type natriuretic peptide levels in patients with paroxysmal and persistent atrial fibrillation undergoing pulmonary vein isolation. | Atrial fibrillation (AF) is the most common cardiac arrhythmia reducing the health-related quality of life. Radiofrequency catheter ablation (CA) became the therapy of choice in patients with drug-resistant AF with success rates between 30% and 86%. However, CA remains a challenging intervention with major complications in about 5% of cases. Therefore, stratification into high and low success patient groups would be helpful. The aim of this study was to investigate the predictive value of B-type natriuretic peptide (BNP) on the outcome of pulmonary vein isolation (PVI) in patients with paroxysmal (PAF) and persistent (Pers-AF) atrial fibrillation.</AbstractText>In 73 patients (median age 53 years, 77% men) undergoing PVI for drug-refractory PAF (n = 45) or Pers-AF (n = 28), the serum BNP concentration was measured before and 3 months after the ablation procedure to assess any association of pre- and post-interventional BNP concentrations with therapeutic outcome. The patients had suffered from AF for a median of 40 months. No patient had structural heart disease or an impaired left-ventricular ejection fraction.</AbstractText>A total of 54 patients (74%) had stable sinus rhythm 3 months after PVI. The median baseline BNP levels in both PAF and Pers-AF patients were significantly lower in patients with a 3-month successful PVI than those in which it was unsuccessful, 57.5 pg/ml (20.4-87.9) versus 159.0 pg/ml (124.1-177.5; p = 0.001) in PAF patients and 90.3 pg/ml (41.0-155.0) versus 176 pg/ml (89.6-297.4; p = 0.026) in patients with Pers-AF, respectively. A multiple logistic regression analysis identified pre-interventional BNP levels as the only independent predictor for 3-month PVI outcomes (p = 0.010). Nevertheless, in this study, the predictive value of BNP for PVI outcomes was not high enough to permit individual outcome prediction. After successful PVI, BNP levels were significantly lower in patients with PAF and Pers-AF (median changes -16.9 and -23.8 pg/ml; p = 0.010 and p = 0.022, respectively), but not in patients with AF in follow-up (median change 9.0 pg/ml and -29.6 pg/ml; p = 1.000 and p = 0.109, respectively).</AbstractText>Pre-ablation BNP level seems to be an independent marker for successful PVI procedures in patients with paroxysmal and persistent AF; however, the observed level of association is moderate.</AbstractText> |
15,506 | Minocycline attenuates ischemia-induced ventricular arrhythmias in rats. | Minocycline has been shown to protect against myocardial ischemia-reperfusion injury. This study investigated the effects of minocycline on ischemia-induced ventricular arrhythmias in rats. Anesthetized male rats were once treated with minocycline (45mg/kg, i.p.) 1h before ischemia in the absence and/or presence of 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002, 0.3mg/kg, i.v., a PI3K inhibitor) and 5-hydroxydecanoic acid [5-HD, 10mg/kg, i.v., a specific inhibitor of mitochondrial ATP-sensitive potassium (K(ATP)) channels] which were once injected 10min before ischemia and then subjected to ischemia for 30min. Ventricular arrhythmias were assessed. L-type Ca(2+) current was measured by the patch-clamp technique. During the 30-minute ischemia, minocycline significantly reduced the incidence of ventricular fibrillation (VF) (P<0.05). The duration of VT+VF, the number of VT+VF episodes and the severity of arrhythmias were all significantly reduced by minocycline compared to those in myocardial ischemia group (P<0.05 for all). Administration of LY294002 or 5-HD abolished the protective effects of minocycline on VF incidence, the duration of VT+VF, the number of VT+VF episodes and the severity of arrhythmias (P<0.05 for all). In addition, minocycline inhibited L-type Ca(2+) currents of normal myocardial cell membrane in a dose-dependent manner. This study suggested that minocycline could attenuate ischemia-induced ventricular arrhythmias in rats in which PI3K/Akt signaling pathway, mitochondrial K(ATP) channels and L-type Ca(2+) channels may be involved. |
15,507 | Extracorporeal life support following out-of-hospital refractory cardiac arrest. | Extracorporeal life support (ECLS) has recently shown encouraging results in the resuscitation of in-hospital (IH) refractory cardiac arrest. We assessed the use of ECLS following out-of-hospital (OH) refractory cardiac arrest.</AbstractText>We evaluated 51 consecutive patients who experienced witnessed OH refractory cardiac arrest and received automated chest compression and ECLS upon arrival in the hospital. Patients with preexisting severe hypothermia who experienced IH cardiac arrest were excluded. A femorofemoral ECLS was set up on admission to the hospital by a mobile cardiothoracic surgical team.</AbstractText>Fifty-one patients were included (mean age, 42 ± 15 years). The median delays from cardiac arrest to cardiopulmonary resuscitation and ECLS were, respectively, 3 minutes (25th to 75th interquartile range, 1 to 7) and 120 minutes (25th to 75th interquartile range, 102-149). Initial rhythm was ventricular fibrillation in 32 patients (63%), asystole in 15 patients (29%) patients and pulseless rhythm in 4 patients (8%). ECLS failed in 9 patients (18%). Only two patients (4%) (95% confidence interval, 1% to 13%) were alive at day 28 with a favourable neurological outcome. There was a significant correlation (r = 0.36, P = 0.01) between blood lactate and delay between cardiac arrest and onset of ECLS, but not with arterial pH or blood potassium level. Deaths were the consequence of multiorgan failure (n = 43; 47%), brain death (n = 10; 20%) and refractory hemorrhagic shock (n = 7; 14%), and most patients (n = 46; 90%) died within 48 hours.</AbstractText>This poor outcome suggests that the use of ECLS should be more restricted following OH refractory cardiac arrest.</AbstractText> |
15,508 | Improvements of cardiac electrophysiologic stability and ventricular fibrillation threshold in rats with myocardial infarction treated with cardiac stem cells. | Arrhythmia is of concern after cardiac stem cell transplantation in repairing infarcted myocardium. However, whether transplantation improved the ventricular fibrillation threshold and whether severe malignant ventricular arrhythmia is induced in the myocardial infarction model are still unclear. We sought to investigate the electrophysiologic characteristics and ventricular fibrillation threshold in rats with myocardial infarction by treatment with allogeneic cardiac stem cells.</AbstractText>Prospective, randomized, controlled study.</AbstractText>University-affiliated hospital.</AbstractText>Male Sprague-Dawley rats.</AbstractText>Myocardial infarction was induced in 20 male Sprague-Dawley rats. Two weeks later, animals were randomized to receive 5 × 10(6) cardiac stem cells labeled with PKH26 in phosphate buffer solution or a phosphate buffer solution-alone injection into the infarcted anterior ventricular-free wall.</AbstractText>Six weeks after the cardiac stem cell or phosphate buffer solution injection, electrophysiologic characteristics and ventricular fibrillation threshold were measured at the infarct area, infarct marginal zone, and noninfarct zone. Labeled cardiac stem cells were observed in 5-μm cryostat sections from each harvested heart. The unipolar electrogram activation recovery time dispersions were shorter in the cardiac stem cell group compared with those at the phosphate buffer solution group (15.5 ± 4.4 vs. 38.6 ± 14.9 msecs, p = .000177). Malignant ventricular arrhythmias were significantly (p = .00108) less inducible in the cardiac stem cell group (one of ten) than the phosphate buffer solution group (nine of ten). The ventricular fibrillation thresholds were greatly improved in the cardiac stem cell group compared with the phosphate buffer solution group. Labeled cardiac stem cells were identified in the infarct zone and infarct marginal zone and expressed Connexin-43, von Willebrand factor, α-smooth muscle actin, and α-sarcomeric actin.</AbstractText>Cardiac stem cells may modulate the electrophysiologic abnormality and improve the ventricular fibrillation threshold in rats with myocardial infarction treated with allogeneic cardiac stem cells and cardiac stem cell express markers that suggest muscle, endothelium, and vascular smooth muscle phenotypes in vivo.</AbstractText> |
15,509 | Influenza A(H1N1) infection and severe cardiac dysfunction in adults: A case series. | While viral myocarditis and heart failure are recognized and feared complications of seasonal influenza A infection, only limited information is available for 2009 influenza A(H1N1)-induced heart failure.</AbstractText>This case series summarizes the disease course of four patients with 2009 influenza A(H1N1) infection who were treated at our institution from November 2009 until September 2010. All patients presented with severe cardiac dysfunction (acute heart failure, cardiogenic shock or cardiac arrest due to ventricular fibrillation) as the leading symptom of influenza A(H1N1) infection. Two patients most likely had pre-existent cardiac pathologies, and three required catecholamine therapy to maintain hemodynamic function. Except for one patient who died before influenza A(H1N1) infection had been diagnosed, all patients received antiviral therapy with oseltamivir and supportive critical care. Acute respiratory distress syndrome due to influenza A(H1N1) infection developed in one patient. Heart function normalized in two of the three surviving patients but remained impaired in the other one at hospital discharge.</AbstractText>Influenza A(H1N1) infection may be associated with severe cardiac dysfunction which can even be the leading clinical symptom at presentation. During an influenza pandemic, a thorough history may reveal flu-like symptoms and should indicate testing for H1N1 infection also in critically ill patients with acute heart failure.</AbstractText> |
15,510 | Serial assessment of the electrocardiographic strain pattern for prediction of new-onset heart failure during antihypertensive treatment: the LIFE study. | Although the presence of the electrocardiographic (ECG) strain pattern has been associated with an increased risk of developing heart failure (HF), the relationship of regression vs. persistence vs. development of new ECG strain to subsequent HF is unclear.</AbstractText>Electrocardiographic strain was evaluated at baseline and at year-1 in 7265 hypertensive patients without HF treated with atenolol- or losartan-based regimens. During 3.9 ± 0.7 years of follow-up after the year-1 ECG, 154 patients (2.1%) were hospitalized for HF. Five-year HF incidence was lowest in patients with no ECG strain (1.6%), intermediate in patients with regression of strain (5.4%), and highest in patients with persistent (7.1%) or new strain (7.0%; P< 0.0001 across groups). In the Cox multivariable analyses adjusting for the known predictive value of in-treatment ECG left ventricular hypertrophy by the Cornell product and Sokolow-Lyon voltage, in-treatment QRS duration, systolic and diastolic pressure, incident myocardial infarction and atrial fibrillation, randomized treatment and other risk factors for HF, regression of strain [hazards ratio (HR) 2.4, 95% confidence interval (CI) 1.2-5.0], persistence of strain (HR 1.9, 95% CI 1.2-3.2), and development of new ECG strain (HR 2.3, 95% CI 1.2-4.4) were all independently associated with an increased risk of new HF compared with the absence of ECG strain on both baseline and year-1 ECGs.</AbstractText>The development of new ECG strain or persistence of ECG strain between baseline and year-1 is associated with an increased risk of HF. The regression of ECG strain between baseline and year-1 does not convey a decreased risk of HF.</AbstractText>http://clinicaltrials.gov/ct/show/NCT00338260.</AbstractText> |
15,511 | Performance of an automated external defibrillator during simulated rotor-wing critical care transports. | This study aimed to evaluate whether an automated external defibrillator (AED) was accurate enough to analyze the heart rhythm during a simulated rotor wing critical care transport. We hypothesized that AED analysis of the simulated rhythms during a helicopter flight would result in significant errors (i.e., inappropriate shocks, analysis delay).</AbstractText>Three commercial AEDs were tested for analyzing the heart rhythm in a helicopter using a manikin and a human volunteer. Ventricular fibrillation (VF), sinus rhythm, and asystole were simulated by using an arrhythmia simulator of the manikin. The intervals from analysis to shock recommendation were collected on a stationary and in-motion helicopter. Sensitivity and specificity of three AEDs were also calculated. Vibration intensities were measured with a digital vibration meter placed on the chest of the manikin/human volunteer both on the stretcher and on the floor of the helicopter.</AbstractText>All AEDs correctly recommended shock delivery for the cardiac rhythms of the manikin. Sensitivity for VF was 100.0% (95% CI 91.2-100.0) and specificity for sinus rhythm and asystole were 100.0% (95% CI 91.2-100.0). Although the recorded ECG rhythms of the volunteer in an in-motion helicopter showed baseline artifacts, all AEDs analyzed the cardiac rhythm of the volunteer correctly and did not recommend shock delivery. On the floor of the helicopter, the median measured vibration intensity was 6.6 m/s(2) (IQR 5.5-7.7 m/s(2)) with significantly less vibrations transmitted to the manikin/human volunteer chest (manikin median 3.1 m/s(2), IQR 2.2-4.0 m/s(2); human volunteer median 0.95 m/s(2), IQR 0.65-1.25 m/s(2)).</AbstractText>This study suggested that current AEDs could analyze the heart rhythm correctly during simulated helicopter transport. Further studies using an animal model would be needed before applying to patients.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,512 | Exploiting correlation of ECG with certain EMD functions for discrimination of ventricular fibrillation. | Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia. A high impulse current is required in this stage to save lives. In this paper, an empirical mode decomposition (EMD) based algorithm is presented to separate VF from other arrhythmias. The characteristics of the VF signal has high degree of similarity with the intrinsic mode functions (IMFs) of the EMD decomposition in comparison to other ECG pathologies. This high correlation between the VF signal and its certain IMFs is exploited to separate VF from other cardiac pathologies. Reliable databases are used to verify effectiveness of our algorithm and the results demonstrate superiority of our proposed technique compared to other well-known techniques of VF discrimination. |
15,513 | Occupational affiliation does not influence practical skills in cardiopulmonary resuscitation for in-hospital healthcare professionals. | D-CPR (Defibrillator Cardiopulmonary Resuscitation) is a technique for optimal basic life support during cardiopulmonary resuscitation (CPR). Guidelines recommend that healthcare professionals can perform CPR with competence. How CPR training and provision is organized varies between hospitals, and it is our impression that in Sweden this has generally improved during the last 15-20 years. However, some hospitals still do not have any AED (Automated External Defibrillators). The aim was to investigate potential differences in practical skills between different healthcare professions before and after training in D-CPR.</AbstractText>Seventy-four healthcare professionals were video recorded and evaluated for adherence to a modified Cardiff Score. A Laerdal Resusci Anne manikin in connection to PC Skill reporting System was used to evaluate CPR quality. A simulated CPR situation was accomplished during a 5-10 min scenario of ventricular fibrillation. Paired and unpaired statistical methods were used to examine differences within and between occupations with respect to the intervention.</AbstractText>There were no differences in skills among the different healthcare professions, except for compressions per minute. In total, the number of compression per minute and depth improved for all groups (P < 0.001). In total, 41% of the participants used AED before and 96% of the participants used AED after the intervention (P < 0.001). Before intervention, it took a median time of 120 seconds until the AED was used; after the intervention, it took 82 seconds.</AbstractText>Nearly all healthcare professionals learned to use the AED. There were no differences in CPR skill performances among the different healthcare professionals.</AbstractText> |
15,514 | Effects of chronic amiodarone on the electrical restitution in the human ventricle with reference to its antiarrhythmic efficacy. | Dynamic instability of ventricular refractoriness represented by electrical restitution operates synergistically with tissue heterogeneity to increase the propensity for functional reentry leading to ventricular tachycardia/fibrillation (VT/VF). Little is known about the effect of chronic amiodarone on the electrical restitution in the human ventricle.</AbstractText>Restitution kinetics of monophasic action potential duration (MAPD(90)) in the right ventricular outflow tract (RVOT) and apex (RVA), and of inverse of conduction time from RVOT to RVA (CT(-1)), were estimated by an S1-S2 protocol in 22 patients treated with amiodarone (180 ± 33 mg/day for 7 ± 9 months) and in 30 without treatment. In the untreated patients, the restitution kinetics of CT(-1) was steeper in the group with structural heart disease (SHD) (UNT(SHD+), n = 18) than without SHD (UNT(SHD-), n = 12), whereas MAPD(90) restitution parameters were comparable. In the amiodarone-treated patients (all with SHD), the shortest diastolic interval to produce a ventricular response (DI(min)) was increased, the maximum slope of MAPD(90) was flattened, and the magnitude of CT(-1) restitution was reduced as compared with UNT(SHD+). Sustained VT/VF was induced in 7 of 18 UNT(SHD+) (38.9%) and in 4 of 22 amiodarone-treated patients (18.2%, P = 0.07). Concomitant presence of increased CT(-1) restitution and dispersion of MAPD(90) restitution was required for the VT/VF induction. The suppression of VT/VF in the amiodarone-treated patients was associated with a smaller magnitude of CT(-1) restitution in the presence of limited dispersion of MAPD(90) restitution.</AbstractText>Chronic amiodarone flattens restitution kinetics of MAPD(90) and CT(-1) in the human ventricle, which could be antiarrhythmic in patients with limited tissue heterogeneity.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,515 | Preprocedural predictors of atrial fibrillation recurrence following pulmonary vein antrum isolation in patients with paroxysmal atrial fibrillation: long-term follow-up results. | The objective of this study was to identify the simple preprocedural parameters of atrial fibrillation (AF) recurrence following single ablation procedure in patients with paroxysmal AF during long-term follow-up period.</AbstractText>Consecutive 474 patients (61 ± 10 years; 364 males, left atrial (LA) diameter 37.6 ± 5.1 mm) with drug-refractory paroxysmal AF who underwent AF ablation were analyzed. Pulmonary vein antrum isolation (PVAI), cavotricuspid isthmus line creation with bidirectional conduction block, and elimination of all non-PV triggers of AF were performed in all patients. With a mean follow-up of 30 ± 13 months after single procedure, 318 patients (67.1%) were in sinus rhythm without any antiarrhythmic drugs. Multivariate analysis using Cox's proportional hazards model, including the age, gender, duration of AF, body mass index, LA size, left ventricular ejection fraction, and presence of hypertension and structural heart disease as variables, demonstrated that LA size was an independent predictor of AF recurrences after PVAI with a 7.2% increase in the probability for every 1 mm increase in LA diameter (P = 0.0007). When the patients were categorized into 3 groups according to the LA diameter, the patients with moderate (40-50 mm) and severe dilatation (>50 mm) had a 1.30-fold (P = 0.0131) and 2.14-fold (P = 0.0057) increase, respectively, in the probability of recurrent AF as compared with the patients with normal LA diameter (≤40 mm).</AbstractText>In the long-term follow-up period, LA size was the best preprocedural predictor of AF recurrence following single ablation procedure in the patients with paroxysmal AF, even in the patients with a relatively small LA.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,516 | Congestive heart failure after extensive catheter ablation for atrial fibrillation: prevalence, characterization, and outcome. | This study sought to describe a new complication of catheter ablation for atrial fibrillation (AF): new onset congestive heart failure (CHF) after extensive ablation for AF.</AbstractText>Data from 12 patients developing CHF after ablation were prospectively collected. All patients underwent extensive ablation for AF including circumferential pulmonary venous ablation and complex fractionated atrial electrograms guided ablation. CHF was diagnosed using the following criteria: symptoms or signs of heart failure, elevated BNP, and echocardiographic evidence of left ventricular diastolic dysfunction. Twelve patients (5 persistent and 7 permanent AF) had CHF after extensive ablation out of 484 consecutive AF patients who underwent catheter ablation (prevalence 2.5%). None of these 12 patients had CHF prior to the procedure. The mean onset of the symptoms was 39 ± 14 hours after the index procedure. Dyspnea and pulmonary rales were the most observed symptoms or signs. White blood cell count, serum CRP, BNP, and echocardiographic parameters of left ventricular diastolic dysfunction (E/A, E/E') were significantly increased after the onset of symptoms. All patients had complete recovery with supportive therapy within 3 days of the onset of symptoms.</AbstractText>In this single-center experience, CHF after extensive ablation for AF was a well-recognized complication with a relatively high incidence of 2.5%. Measurement of BNP, CRP, and E/A, E/E' is useful in managing these patients.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,517 | Sudden death of an immunocompetent young adult caused by novel (swine origin) influenza A/H1N1-associated myocarditis. | The main cause of death from novel (swine origin) influenza A/H1N1 infection is acute respiratory distress syndrome. Most fatal cases are immunocompromised patients or patients with a severe underlying disease. Here, we report a fatal case of acute interstitial myocarditis associated with novel influenza A/H1N1 infection in an immunocompetent young woman. A previously healthy 18-year-old woman experienced malaise, diarrhea, and fever for several days prior to a sudden collapse at home. Autopsy revealed a predominantly lymphocytic myocarditis in the absence of a significant respiratory tract infection. Infection with novel (swine origin) influenza A/H1N1 was confirmed by PCR analysis of blood as well as myocardial tissue. Influenza-caused diarrhea with consecutive hypokalemia potentially contributed to the fatal outcome of the myocarditis, characterized by ventricular fibrillation. In conclusion, sudden death by myocarditis may be a rare complication of novel influenza A/H1N1 infection in otherwise healthy individuals, even in the absence of significant respiratory tract infection. |
15,518 | Low levels of the omega-3 index are associated with sudden cardiac arrest and remain stable in survivors in the subacute phase. | In previous studies, low blood levels of n-3 fatty acids (FA) have been associated with increased risk of cardiac death, and the omega-3 index (red blood cell (RBC) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) expressed as weight percentage of total FA) has recently been proposed as a new risk factor for death from coronary artery disease, especially following sudden cardiac arrest (SCA). As blood samples often haven been harvested after the event, the aim of our study was to evaluate the stability of RBC fatty acids following SCA. The total FA profile, including the omega-3 index, was measured three times during the first 48 h in 25 survivors of out-of-hospital cardiac arrest (OHCA), in 15 patients with a myocardial infarction (MI) without SCA and in 5 healthy subjects. We could not demonstrate significant changes in the FA measurements in any of the groups, this also applied to the omega-6/omega-3 ratio and the arachidonic acid (AA)/EPA ratio. Furthermore, we compared the omega-3 index in 14 OHCA-patients suffering their first MI with that of 185 first-time MI-patients without SCA; mean values being 4.59% and 6.48%, respectively (p = 0.002). In a multivariate logistic regression analysis, a 1% increase of the omega-3 index was associated with a 58% (95% CI: 0.25-0.76%) reduction in risk of ventricular fibrillation (VF). In conclusion, the omega-3 index remained stable after an event of SCA and predicted the risk of VF. |
15,519 | The GeoForm annuloplasty ring for the surgical treatment of functional mitral regurgitation in advanced dilated cardiomyopathy. | To assess the results of the three-dimensional (3D)-shaped GeoForm ring for the treatment of functional mitral regurgitation (FMR).</AbstractText>Seventy-four patients with severe FMR and systolic dysfunction underwent GeoForm ring implantation. Forty-six patients (62%) were in the New York Heart Association (NYHA) class III-IV. Concomitant procedures were coronary artery bypass grafting (CABG) (33 patients (pts)), tricuspid repair (23 pts), atrial fibrillation ablation (20 pts), aortic valve replacement (eight pts) and left-ventricular (LV) reconstruction (five pts).</AbstractText>Hospital mortality was 9%. Three more patients died after hospital discharge. Overall survival was 81.1 ± 6.6% at 3.5 years. The 67 hospital survivors underwent clinical and echocardiographic follow-up at a mean follow-up period of 1.9 ± 1.25 years (median 1.7 years). MR was absent or mild in 83% of the patients (56/67), moderate in 7% (5/67), and moderate to severe in the remaining 9% (6/67). At 3.5 years, overall freedom from MR ≥ 3+ was 85.1 ± 8% and freedom from MR ≥ 2+ was 75.1 ± 8.6%. Statistical analysis identified preoperative asymmetric tethering with prevalent restricted motion of the posterior leaflet as the only predictor of recurrence of MR ≥ 2+ (hazard ratio (HR) 6.1, p=0.005). Reverse LV remodeling was demonstrated in 31 of the 54 patients eligible for this specific analysis (31/54, 57%): Both LV end-diastolic and end-systolic volumes indexed significantly decreased (both p=0.0001) as well as systolic pulmonary artery pressure (SPAP) (p=0.006). Ejection fraction increased from 33 ± 8% to 43 ± 8% (p<0.0001). Stress echocardiography was performed in a subgroup of eight patients. Mean mitral area at rest was 2.2 ± 0.3 cm² and did not change during stress. Cardiac output significantly increased in all patients during exercise. Although mean and peak transmitral gradients were 3.3 ± 1.3 and 8.1 ± 2.2 mmHg at rest and 6.6 ± 2.5 and 14.8 ± 3.9 mmHg under stress, respectively (both p<0.003), the increase in SPAP was not statistically significant (28 ± 3.0 vs 31 ± 7.5 mm Hg, p=0.17), revealing a preserved cardiac adaptation to exercise.</AbstractText>The GeoForm ring is effective in relieving FMR in most of the patients with dilated cardiomyopathy. In presence of prevalent restricted motion of the posterior leaflet, recurrence of significant MR is more likely to occur. Clinically relevant mitral stenosis was not detected during exercise.</AbstractText>Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
15,520 | Iodine-123 mIBG Imaging for Predicting the Development of Atrial Fibrillation. | we investigated whether cardiac sympathetic nervous system (SNS) activity measured by iodine-123 meta-iodobenzylguanidine ((123)I-mIBG) imaging would be associated with both the occurrence of heart failure (HF) and the transit to permanent atrial fibrillation (AF) in patients with paroxysmal AF.</AbstractText>atrial fibrillation occurs suddenly and transiently and can persist, and results in the occurrence of HF. An important feature of AF and HF is their propensity to coexist not only because they share antecedent risk factors, but also because the one may directly predispose the heart to the other. However, a useful modality for predicting the occurrences of both those has not been established in patients with paroxysmal AF.</AbstractText>the (123)I-mIBG scintigraphy was performed to evaluate cardiac SNS activity presented as the heart/mediastinum ratio in 98 consecutive patients (age 66 ± 13 years, 63.3% male) with idiopathic paroxysmal AF and preserved left ventricular ejection fraction (≥ 50%).</AbstractText>during 4 ± 3.6 years of follow-up, the transit to permanent AF was associated with the occurrence of HF (34.3% in 12 of 35 patients with permanent AF vs. 6.3% in 4 of 63 patients without, p < 0.0001). Lower heart/mediastinum ratio and lower left ventricular ejection fraction were the independent predictors of the transit to permanent AF with adjusted hazard ratios of 3.44 (95% confidence interval [CI]: 1.9 to 6.2, p < 0.0001) and 1.04 (95% CI: 1.01 to 1.08, p = 0.014). Further, these factors and higher plasma brain natriuretic peptide concentration were the independent predictors of the occurrence of HF with permanent AF, with adjusted hazard ratios of 5.08 (95% CI: 1.5 to 17.5, p = 0.011), 1.11 (95% CI: 1.03 to 1.19, p = 0.004), and 1.004 (95% CI: 1.001 to 1.008, p = 0.014).</AbstractText>cardiac SNS abnormality was associated with the occurrence of both HF and permanent AF in paroxysmal AF patients, and (123)I-mIBG imaging may be a useful modality for predicting the development of AF.</AbstractText>2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,521 | Real-time 3D echo in patient selection for cardiac resynchronization therapy. | this study investigated the use of 3-dimensional (3D) echo in quantifying left ventricular mechanical dyssynchrony (LVMD), its interhospital agreement, and potential impact on patient selection.</AbstractText>assessment of LVMD has been proposed as an improvement on conventional criteria in selecting patients for cardiac resynchronization therapy (CRT). Three-dimensional echo offers a reproducible assessment of left ventricular (LV) structure, function, and LVMD and may be useful in selecting patients for this intervention.</AbstractText>we studied 187 patients at 2 institutions. Three-dimensional data from baseline and longest follow-up were quantified for volume, left ventricular ejection fraction (LVEF), and systolic dyssynchrony index (SDI). New York Heart Association (NYHA) functional class was assessed independently. Several outcomes from CRT were considered: 1) reduction in NYHA functional class; 2) 20% relative increase in LVEF; and 3) 15% reduction in LV end-systolic volume. Sixty-two cases were shared between institutions to analyze interhospital agreement.</AbstractText>there was excellent interhospital agreement for 3D-derived LV end-diastolic and end- systolic volumes, EF, and SDI (variability: 2.9%, 1%, 7.1%, and 7.6%, respectively). Reduction in NYHA functional class was found in 78.9% of patients. Relative improvement in LVEF of 20% was found in 68% of patients, but significant reduction in LV end-systolic volume was found in only 41.5%. The QRS duration was not predictive of any of the measures of outcome (area under the curve [AUC]: 0.52, 0.58, and 0.57 for NYHA functional class, LVEF, and LV end-systolic volume), whereas SDI was highly predictive of improvement in these parameters (AUC: 0.79, 0.86, and 0.66, respectively). For patients not fulfilling traditional selection criteria (atrial fibrillation, QRS duration <120 ms, or undergoing device upgrade), SDI had similar predictive value. A cutoff of 10.4% for SDI was found to have the highest accuracy for predicting improvement following CRT.</AbstractText>the LVMD quantification by 3D echo is reproducible between centers. SDI was an excellent predictor of response to CRT in this selected patient cohort and may be valuable in identifying a target population for CRT irrespective of QRS morphology and duration.</AbstractText>2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,522 | Suppression of re-entrant and multifocal ventricular fibrillation by the late sodium current blocker ranolazine. | The purpose of this study was to test the hypothesis that the late Na current blocker ranolazine suppresses re-entrant and multifocal ventricular fibrillation (VF).</AbstractText>VF can be caused by either re-entrant or focal mechanism.</AbstractText>Simultaneous voltage and intracellular Ca(+)² optical mapping of the left ventricular epicardial surface along with microelectrode recordings was performed in 24 isolated-perfused aged rat hearts. Re-entrant VF was induced by rapid pacing and multifocal VF by exposure to oxidative stress with 0.1 mM hydrogen peroxide (H₂O₂).</AbstractText>Rapid pacing induced sustained VF in 7 of 8 aged rat hearts, characterized by 2 to 4 broad propagating wavefronts. Ranolazine significantly (p < 0.05) reduced the maximum slope of action potential duration restitution curve and converted sustained to nonsustained VF lasting 24 ± 8 s in all 7 hearts. Exposure to H₂O₂ initiated early afterdepolarization (EAD)-mediated triggered activity that led to sustained VF in 8 out of 8 aged hearts. VF was characterized by multiple foci, appearing at an average of 6.8 ± 3.2 every 100 ms, which remained confined to a small area averaging 2.8 ± 0.85 mm² and became extinct after a mean of 43 ± 16 ms. Ranolazine prevented (when given before H₂O₂) and suppressed H₂O₂-mediated EADs by reducing the number of foci, causing VF to terminate in 8 out of 8 hearts. Simulations in 2-dimensional tissue with EAD-mediated multifocal VF showed progressive reduction in the number of foci and VF termination by blocking the late Na current.</AbstractText>Late Na current blockade with ranolazine is effective at suppressing both pacing-induced re-entrant VF and EAD-mediated multifocal VF.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,523 | Left atrial strain predicts reverse remodeling after catheter ablation for atrial fibrillation. | The purpose of this study was to assess left atrial (LA) strain during long-term follow-up after catheter ablation for atrial fibrillation and to find predictors for LA reverse remodeling.</AbstractText>The association between LA reverse remodeling and improvement in LA strain after catheter ablation has not been investigated thus far.</AbstractText>In 148 patients undergoing catheter ablation for atrial fibrillation, LA volumes and LA strain were assessed with echocardiography at baseline and after a mean of 13.2 ± 6.7 months of follow-up. The study population was divided according to LA reverse remodeling at follow-up: responders were defined as patients who exhibited 15% or more reduction in maximum LA volume at long-term follow-up. Left atrial systolic (LAs) strain was assessed with tissue Doppler imaging.</AbstractText>At follow-up, 93 patients (63%) were classified as responders, whereas 55 patients (37%) were nonresponders. At baseline, LAs strain was significantly higher in the responders as compared with the nonresponders (19 ± 8% vs. 14 ± 6%; p = 0.001). Among the responders, a significant increase in LAs strain was noted from baseline to follow-up (from 19 ± 8% to 22 ± 9%; p < 0.05), whereas no change was noted among the nonresponders. LAs strain at baseline was an independent predictor of LA reverse remodeling (odds ratio: 1.813; 95% confidence interval: 1.102 to 2.982; p = 0.019).</AbstractText>In the present study, 63% of the patients exhibited LA reverse remodeling after catheter ablation for atrial fibrillation, with a concomitant improvement in LA strain. LA strain at baseline was an independent predictor of LA reverse remodeling.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,524 | A randomized active-controlled study comparing the efficacy and safety of vernakalant to amiodarone in recent-onset atrial fibrillation. | This randomized double-blind study compared the efficacy and safety of intravenous vernakalant and amiodarone for the acute conversion of recent-onset atrial fibrillation (AF).</AbstractText>Intravenous vernakalant has effectively converted recent-onset AF and was well tolerated in placebo-controlled studies.</AbstractText>A total of 254 adult patients with AF (3 to 48 h duration) eligible for cardioversion were enrolled in the study. Patients received either a 10-min infusion of vernakalant (3 mg/kg) followed by a 15-min observation period and a second 10-min infusion (2 mg/kg) if still in AF, plus a sham amiodarone infusion, or a 60-min infusion of amiodarone (5 mg/kg) followed by a maintenance infusion (50 mg) over an additional 60 min, plus a sham vernakalant infusion.</AbstractText>Conversion from AF to sinus rhythm within the first 90 min (primary end point) was achieved in 60 of 116 (51.7%) vernakalant patients compared with 6 of 116 (5.2%) amiodarone patients (p < 0.0001). Vernakalant resulted in rapid conversion (median time of 11 min in responders) and was associated with a higher rate of symptom relief compared with amiodarone (53.4% of vernakalant patients reported no AF symptoms at 90 min compared with 32.8% of amiodarone patients; p = 0.0012). Serious adverse events or events leading to discontinuation of study drug were uncommon. There were no cases of torsades de pointes, ventricular fibrillation, or polymorphic or sustained ventricular tachycardia.</AbstractText>Vernakalant demonstrated efficacy superior to amiodarone for acute conversion of recent-onset AF. Both vernakalant and amiodarone were safe and well tolerated in this study. (A Phase III Superiority Study of Vernakalant vs Amiodarone in Subjects With Recent Onset Atrial Fibrillation [AVRO]; NCT00668759).</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,525 | A case of inefficient defibrillation during thoracotomy. | We describe the case of an accidental intraoperative ventricular fibrillation that could not be interrupted by a 35-J shock fired by an implantable cardioverter defibrillator (ICD). We believe that the iatrogenic pneumothorax induced by thoracotomy during the epicardial lead implant temporarily changed the intrathoracic impedance, causing an increase in defibrillation threshold. This possible change in impedance with resulting ineffective interruption of arrhythmia should be taken in consideration when a thoracotomy is planned in a patient bearing an ICD.  |
15,526 | Cardiogenetic screening of first-degree relatives after sudden cardiac death in the young: a population-based approach. | To investigate the yield of cardiogenetic screening of relatives of young sudden cardiac death (SCD) and sudden unexplained death (SUD) victims in a population-based setting.</AbstractText>A population-based study was carried out between 2000 and 2006. Records of the hospital, death declaration certificates, and resuscitation records were reviewed for SCD and SUD cases (1-40 years). Information on autopsy results and cardiogenetic screening of the victims' first-degree relatives was collected. Relatives were invited for additional cardiogenetic screening when this had not yet been performed. The search led to 16 cases of SCD/SUD and 4 cases of aborted SCD/SUD. Causes of SCD/SUD were myocardial infarction (n = 3), arrhythmogenic right ventricular cardiomyopathy (ARVC) (n = 2), long-QT syndrome (n = 1), hypertrophic cardiomyopathy (n = 2), left ventricular hypertrophy due to aortic stenosis (n = 1), and unknown cause of death (n = 7). Causes of aborted SCD/SUD were myocardial infarction (n = 2), idiopatic ventricular fibrillation (n = 1), and the Brugada syndrome (n = 1). The cardiogenetic screening of 37 relatives of 12 victims led to a diagnosis of Brugada syndrome in 3 relatives and the suspicion of ARVC in 2 relatives. The yield of screening of these relatives was 14% (95% confidence interval: 3-25%).</AbstractText>In the usual care, relatives of (aborted) SCD and SUD victims are often not referred for cardiogenetic screening. Screening is often not performed according to a systematic approach, and the detection rate of inherited diseases in relatives of (aborted) SCD and SUD victims in a population-based setting, although substantial, is lower than expected based on previous studies.</AbstractText> |
15,527 | Probability of ventricular fibrillation: allometric model based on the ST deviation. | Allometry, in general biology, measures the relative growth of a part in relation to the whole living organism. Using reported clinical data, we apply this concept for evaluating the probability of ventricular fibrillation based on the electrocardiographic ST-segment deviation values.</AbstractText>Data collected by previous reports were used to fit an allometric model in order to estimate ventricular fibrillation probability. Patients presenting either with death, myocardial infarction or unstable angina were included to calculate such probability as, VFp = δ + β (ST), for three different ST deviations. The coefficients δ and β were obtained as the best fit to the clinical data extended over observational periods of 1, 6, 12 and 48 months from occurrence of the first reported chest pain accompanied by ST deviation.</AbstractText>By application of the above equation in log-log representation, the fitting procedure produced the following overall coefficients: Average β = 0.46, with a maximum = 0.62 and a minimum = 0.42; Average δ = 1.28, with a maximum = 1.79 and a minimum = 0.92. For a 2 mm ST-deviation, the full range of predicted ventricular fibrillation probability extended from about 13% at 1 month up to 86% at 4 years after the original cardiac event.</AbstractText>These results, at least preliminarily, appear acceptable and still call for full clinical test. The model seems promising, especially if other parameters were taken into account, such as blood cardiac enzyme concentrations, ischemic or infarcted epicardial areas or ejection fraction. It is concluded, considering these results and a few references found in the literature, that the allometric model shows good predictive practical value to aid medical decisions.</AbstractText> |
15,528 | The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest. | Partial pressure of end-tidal carbon dioxide (PetCO2) during cardiopulmonary resuscitation (CPR) correlates with cardiac output and consequently has a prognostic value in CPR. In our previous study we confirmed that initial PetCO2 value was significantly higher in asphyxial arrest than in ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) cardiac arrest. In this study we sought to evaluate the pattern of PetCO2 changes in cardiac arrest caused by VF/VT and asphyxial cardiac arrest in patients who were resuscitated according to new 2005 guidelines.</AbstractText>The study included two cohorts of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity (PEA), and cardiac arrest due to arrhythmia with initial rhythm VF or pulseless VT. PetCO2 was measured for both groups immediately after intubation and repeatedly every minute, both for patients with or without return of spontaneous circulation (ROSC). We compared the dynamic pattern of PetCO2 between groups.</AbstractText>Between June 2006 and June 2009 resuscitation was attempted in 325 patients and in this study we included 51 patients with asphyxial cardiac arrest and 63 patients with VF/VT cardiac arrest. The initial values of PetCO2 were significantly higher in the group with asphyxial cardiac arrest (6.74 ± 4.22 kilopascals (kPa) versus 4.51 ± 2.47 kPa; P = 0.004). In the group with asphyxial cardiac arrest, the initial values of PetCO2 did not show a significant difference when we compared patients with and without ROSC (6.96 ± 3.63 kPa versus 5.77 ± 4.64 kPa; P = 0.313). We confirmed significantly higher initial PetCO2 values for those with ROSC in the group with primary cardiac arrest (4.62 ± 2.46 kPa versus 3.29 ± 1.76 kPa; P = 0.041). A significant difference in PetCO2 values for those with and without ROSC was achieved after five minutes of CPR in both groups. In all patients with ROSC the initial PetCO2 was again higher than 1.33 kPa.</AbstractText>The dynamic pattern of PetCO2 values during out-of-hospital CPR showed higher values of PetCO2 in the first two minutes of CPR in asphyxia, and a prognostic value of initial PetCO2 only in primary VF/VT cardiac arrest. A prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until final values. This difference seems to be a useful criterion in pre-hospital diagnostic procedures and attendance of cardiac arrest.</AbstractText> |
15,529 | Device-detected atrial tachyarrhythmias predict adverse outcome in real-world patients with implantable biventricular defibrillators. | The purpose of this analysis was to evaluate the correlation between atrial tachycardia (AT) or atrial fibrillation (AF) and clinical outcomes in heart failure (HF) patients implanted with a cardiac resynchronization therapy defibrillator (CRT-D).</AbstractText>In HF patients, AT and AF have high prevalence and are associated with compromised hemodynamic function.</AbstractText>Forty-four Italian cardiological centers followed up 1,193 patients who received a CRT-D according to current guidelines for advanced HF, New York Heart Association functional class ≥ II, left ventricular ejection fraction ≤ 35%, and QRS complex ≥ 120 ms. All patients were in sinus rhythm at implant.</AbstractText>During a median follow-up period of 13 months, AT/AF >10 min occurred in 361 of 1,193 (30%) patients. The composite end point (deaths or HF hospitalizations) occurred in 174 of 1,193 (14.6%). Multivariate time-dependent Cox regression analyses showed that composite end point risk was higher among patients with device-detected AT/AF (hazard ratio [HR]: 2.16, p = 0.032), New York Heart Association functional class III or IV compared with II (HR: 2.09, p = 0.002), and absence of beta-blockers (HR: 1.36, p = 0.036). Furthermore, the composite end point risk was inversely associated with left ventricular ejection fraction (HR: 1.04, p = 0.045), increasing by a factor of 4% for each 1% decrease in left ventricular ejection fraction.</AbstractText>In HF patients with CRT-D, device-detected AT/AF is associated with a worse prognosis. Continuous device diagnostics monitoring and Web-based alerts may inform the physician of AT/AF occurrences and identify patients at risk of cardiac deterioration or patients with suboptimal rate or rhythm control. (Italian ClinicalService Project; NCT01007474).</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,530 | Establishment of a reperfusion model in rabbits with acute myocardial infarction. | Clinically effective cardioprotection under acute myocardial infarction (AMI) can only be achieved by establishing the mechanisms of reperfusion-induced cardiac cell death. In spite of the numerous earlier studies on the prevention of ischemia-reperfusion injury of myocardium, the problem of cardiac cell death upon reperfusion is not yet resolved. Even though animal models provide an immense opportunity in the understanding of the mechanisms of ischemia-reperfusion injury, clinically relevant animal models through which translation of this knowledge into clinic are lacking. In this work, we have established a reperfusion model in rabbits with induced AMI by obstructing and releasing the left anterior ventricular branch of left circumflex coronary artery, which is clinically more relevant. This was achieved by cutting the two left ribs of the rabbit followed by obstructing and releasing the artery unlike the traditional approach, which involves incision through sternum and blocking the anterior descending coronary artery. This animal model of ischemia-reperfusion more closely mimics the physiological condition and also the trauma the animal suffers is much smaller with higher survival rate and thus is a potentially better model for studying the pathology related to ischemia-reperfusion injury. |
15,531 | Safety and efficacy of ibutilide in cardioversion of atrial flutter and fibrillation. | This article reviews the safety and efficacy of ibutilide for use in patients with atrial fibrillation and flutter. Ibutilide, a class III antiarrhythmic agent, is primarily used for conversion of atrial flutter and fibrillation and is a good alternative to electrical cardioversion. Ibutilide has a conversion rate of up to 75% to 80% in recent-onset atrial fibrillation and flutter; the conversion rate is higher for atrial flutter than for atrial fibrillation. It is also safe in the conversion of chronic atrial fibrillation/flutter among patients receiving oral amiodarone therapy. Ibutilide pretreatment facilitates transthoracic defibrillation and decreases the energy requirement of electrical cardioversion by both monophasic and biphasic shocks. Pretreatment with ibutilide before electrical defibrillation has a conversion rate of 100% compared with 72% with no pretreatment. Ibutilide is also safe and efficient in the treatment of atrial fibrillation in patients who have had cardiac surgery, and in accessory pathway-mediated atrial fibrillation Where the conversion rate of ibutilide is as high as 95%. There is up to a 4% risk of torsade de pointes and a 4.9% risk of monomorphic ventricular tachycardia. Hence, close monitoring in an intensive care unit setting is warranted during and at least for 4 hours after drug infusion. The anticoagulation strategy is the same as for any other mode of cardioversion. |
15,532 | The relationship between right ventricular pacing and atrial fibrillation burden and disease progression in patients with paroxysmal atrial fibrillation: the long-MinVPACE study. | In patients requiring permanent pacemaker implantation for sinus node disease (SND) or atrioventricular (AV) block, right ventricular (RV) pacing has been demonstrated to increase the risk of developing atrial fibrillation (AF). The effects of RV pacing in patients with paroxysmal AF are less well defined. Short- and medium-term studies have suggested no significant correlation between RV pacing and atrial fibrillation burden (AFB) measurement; we sought to assess for an effect in the long-term.</AbstractText>Sixty-six patients were randomized to receive either conventional dual chamber pacing (DDDR, n = 33), or dual chamber minimal ventricular pacing (MinVP, n = 33), for a period of at least 1 year. Patients were reviewed every 6 months and all pacemaker data were downloaded. The primary outcome measures were device-derived AFB and progression to persistent AF. The mean duration of study follow-up was 1.4 ± 0.6 years. Mean ventricular pacing was less in the MinVP cohort compared with the DDDR cohort (5.8 vs. 74.0%, P < 0.001). At follow-up, the device-derived AFB was significantly lower in the MinVP cohort when compared with the DDDR cohort (12.8 ± 15.3% vs. DDDR 47.6 ± 42.2%, P < 0.001). Kaplan-Meier estimates of time to onset of persistent AF showed significant reductions in the rates of persistent AF for MinVP pacing (9%) when compared with conventional DDDR pacing (42%), P = 0.004.</AbstractText>Right ventricular pacing induces increased AFB in patients with paroxysmal AF in the long term. Dual chamber MinVP algorithms result in reduced AFB and reduced disease progression from paroxysmal to persistent AF in the long term.</AbstractText> |
15,533 | Implantable intravascular defibrillator: evaluation of defibrillation waveforms with inferior vena cava electrode system. | A percutaneously placed, totally intravascular defibrillator has been developed that shocks via a right ventricular (RV) single-coil and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC). This study evaluated the defibrillation threshold (DFT) with this electrode configuration to determine the effect of different biphasic waveform tilts and second-phase durations as well as the contribution of the IVC electrode.</AbstractText>Eight Bluetick hounds (wt = 30-40 kg) were anesthetized and the RV coil (first-phase anode) was placed in the RV apex. The intravascular defibrillator (PICD®, Model no. IIDM-G, InnerPulse Inc., Research Triangle Park, NC, USA) was positioned such that the titanium electrodes were in the SVC and IVC . Ventricular fibrillation was electrically induced and a Bayesian up-down technique was employed to determine DFT with two configurations: RV to SVC + IVC and RV to SVC. Three waveform tilts (65%, 50%, and 42%) and two second-phase durations (equal to the first phase [balanced] and truncated at 3 ms [unbalanced]) were randomly tested. The source capacitance of the defibrillator was 120 μF for all waveforms.</AbstractText>DFT with the IVC electrode was significantly lower than without the IVC electrode for all waveforms tested (527 ± 9.3 V [standard error], 14.5 J vs 591 ± 7.4 V, 18.5 J, P < 0.001). Neither waveform tilt nor second-phase duration significantly changed the DFT.</AbstractText>In canines, a totally intravascular implantable defibrillator with electrodes in the RV apex, SVC, and IVC had a DFT similar to that of standard nonthoracotomy lead systems. No significant effect was noted with changes in tilt or with balanced or unbalanced waveforms.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
15,534 | Ventricular tachyarrhythmias in patients receiving an implantable cardioverter-defibrillator for primary versus secondary prophylaxis indications. | Data on the mechanisms of sudden cardiac death are limited and may be biased by delays in rhythm recording and selection bias in survivors. As a result, the relative contributions of monomorphic ventricular tachycardia (VT) (cycle length [CL] > 260 ms), monomorphic fast VT (FVT) (CL ≤ 260 ms), and polymorphic VT (PMVT)/ventricular fibrillation (VF) have not been well characterized nor compared in patients with and without prior arrhythmic events.</AbstractText>A retrospective cohort study of implantable cardioverter-defibrillator (ICD) recipients with primary or secondary implant indications was used to evaluate intracardiac electrograms (EGMs) for the first spontaneous VT/VF resulting in appropriate ICD therapy. EGMs were categorized into VT, FVT, and PMVT/VF based on CL and morphologic criteria.</AbstractText>Of 616 implants, 145 patients (58 [40%] primary indications) received appropriate ICD therapy for VT/VF over mean follow-up of 3.8 ± 3.2 years. Primary implants had more diabetes (28% vs 12%; P = 0.02) and less antiarrhythmic use (15% vs 33%; P = 0.02). In those patients with spontaneous arrhythmia, PMVT/VF occurred in 20.7% of primary versus 21.8% of secondary implants, FVT in 19.0% versus 21.8%, and VT in 60.3% versus 56.4%, respectively (P = 0.88). Spontaneous VT CL was similar regardless of implant indication (284 ± 56 [primary] vs 286 ± 67 ms [secondary]; P = 0.92).</AbstractText>Monomorphic VT is the most common cause of appropriate ICD therapy regardless of implant indication. These results provide insight into the mechanisms of sudden cardiac death and have implications for the use of interventions designed to limit ICD shocks.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
15,535 | Straight screw-in atrial leads "J-post shaped" in right appendage versus J-shaped systems for permanent atrial pacing: a safety comparison. | The reliability of active-fixation atrial leads has been compared with that of passive-fixation leads; comparisons have also been made between straight and J-shaped screw-in lead systems. However, few data are available on procedural and short-term safety. This retrospective study compared the procedural safety of non-pre-shaped screw-in leads with that of passive- and active-fixation J-shaped leads.</AbstractText>From January 2004 to January 2010, 1,464 patients underwent new pacemaker/implantable cardioverter-defibrillator implantation. Of these, 915 (study population) received a passive- or active-fixation pre-J-shaped lead, or a straight screw-in atrial lead; the remaining 549 patients, who received only a ventricular lead, were excluded. The three study groups were: Group S-FIX (165 patients, 18%), receiving a straight screw-in atrial lead (postshaped in the right appendage); Group J-PASS (690 patients, 75.4%), receiving a passive-fixation J-shaped atrial lead; and Group J-FIX (60 patients, 6.6%), receiving an active-fixation screw-in J-shaped atrial lead. Procedural and short-term complication rates were analyzed up to 3 months postimplantation.</AbstractText>One complication occurred in each group (S-FIX 0.6% vs J-PASS 0.1% vs J-FIX 1.6%, P = 0.3, 0.1, and 0.4, respectively, for each comparison). The rate of atrial lead dislodgement was higher in Group J-PASS than in S-FIX but not J-FIX (Group S-FIX 0 vs Group J-PASS 16 vs Group J-FIX 1 dislodgements; P = 0.04 and 0.7, respectively).</AbstractText>Straight screw-in atrial leads, "J-post shaped" in the right appendage, offer better stability than passive-fixation J-shaped leads and display a similarly acceptable safety profile compared with both the J-shaped systems.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
15,536 | Cardiac rhythm management devices and electroconvulsive therapy: a critical review apropos of a depressed patient with a pacemaker. | Electroconvulsive therapy (ECT) is an effective treatment and, with the proper risk-minimizing strategies, is relatively safe even in depressed patients with cardiovascular diseases. Specifically, patients with cardiac rhythm management devices (CRMDs) require particular attention because no controlled trials exist to support current empirical recommendations. We present a depressed patient with a pacemaker successfully treated with ECT, and we critically review the relevant literature. Pooled results from 63 patients and 821 ECT sessions showed that 90% of ECT sessions have been performed on depressed patients with their pacemakers in sensing mode and rate adaptation, where available, activated as well. Only 4% of sessions were performed with those functions disabled, whereas no data was available for 6% of ECT sessions. Pooled results from case series and reports highlight a discrepancy between current clinical practice and many guidelines. Electroconvulsive therapy is probably safe in depressed patients with asynchronous fixed-rate pacemakers, although there is a risk of ventricular tachycardia and fibrillation. A larger body of case series and reports suggests that there might be no need to convert synchronous demand pacemakers to asynchronous fixed-rate pacing. Regarding patients with implantable cardioverter defibrillators, antitachycardia treatment was deactivated during most ECT sessions. In depressed patients with CRMDs anticholinergics might be best avoided. In all cases, proper ECT procedures, namely, patient and pacemaker electrical isolation, strict grounding and adequate muscle relaxation along with interrogation and monitoring of CRMDs before and after each session should ensure uncomplicated electroconvulsive treatments. |
15,537 | Effects of cilostazol in the heart. | Cilostazol is a selective phosphodiesterase 3 (PDE3) inhibitor approved by the Food and Drug Administration for treatment of intermittent claudication. It has also been used in bradyarrhythmic patients to increase heart rates. Recently, cilostazol has been shown to prevent ventricular fibrillation in patients with Brugada syndrome. Cilostazol is hypothesized to suppress transient outward potassium (Ito) current and increase inward calcium current, thus, maintaining the dome (phase 2) of action potential, decreasing transmural dispersion of repolarization and preventing ventricular fibrillation. Although many PDE3 inhibitors have been shown to increase cardiac arrhythmia in heart failure, cilostazol has presented effects that are different from other PDE3 inhibitors, especially adenosine uptake inhibition. Owing to this effect, cilostazol could be an effective cardioprotective drug, with its beneficial effects in preventing arrhythmia. In this review, the cardiac electrophysiological effects of cilostazol are presented and its possible cardioprotective effects, particularly in preventing ventricular fibrillation, are discussed, with emphasis on the need to further verify its clinical benefits. |
15,538 | Electrophysiological and Pharmacological Characteristics of Triggered Activity Elicited in Guinea-Pig Pulmonary Vein Myocardium. | The pulmonary vein is known as an important source of ectopic beats, initiating frequent paroxysms of atrial fibrillation. We analyzed electrophysiological and pharmacological characteristics of triggered activity elicited in the isolated pulmonary vein from the guinea pig. Immediately after the termination of train stimulation (pacing cycle length of 100 ms), spontaneous activities accompanied with phase-4 depolarization were detected in 43 out of 45 pulmonary vein preparations. Such triggered activities were not observed in the isolated left atrium. The incidence of triggered activity was higher at a shorter pacing cycle length (100 - 200 ms), and the coupling interval was shorter at a shorter pacing cycle length. Verapamil (1 μM), ryanodine (0.1 μM), and pilsicainide (10 μM) suppressed the occurrence of triggered activities. The resting membrane potential of the pulmonary vein myocardium was more positive than that of the left atrium. Carbachol (0.3 μM) hyperpolarized the resting membrane potential and completely inhibited the occurrence of triggered activities. These results suggest that the pulmonary veins have more arrhythmogenic features than the left atrium, possibly through lower resting membrane potential. The electrophysiological and pharmacological characteristics of triggered activity elicited in the pulmonary vein myocardium were similar to those previously reported using ventricular tissues. |
15,539 | Carotid-femoral pulse wave velocity is associated with N-terminal pro-B-type natriuretic peptide level in patients with atrial fibrillation. | To determine the extent to which conduit artery stiffness is associated with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with atrial fibrillation (AF).</AbstractText>Cross-sectional study.</AbstractText>National University Hospital, Singapore.</AbstractText>Cases (n=117) were patients with AF onset <65 years of age without heart failure or structural heart disease. Controls (n=274) were patients without AF who were seen at the general cardiology clinic.</AbstractText>Transthoracic echocardiography, carotid-femoral pulse wave velocity (CFPWV) measured using applanation tonometry and blood draw for plasma NT-proBNP at enrolment for all patients.</AbstractText>Plasma NT-proBNP.</AbstractText>In patients with AF, CFPWV was associated with NT-proBNP after adjusting for hypertension and factors that were univariately associated with NT-proBNP: age at enrolment, type of AF, body mass index, left ventricular mass index, left atrial volume index, mitral E/E', mitral deceleration time and use of β-blockers (β=0.234; 95% CI 0.100 to 0.367; p=0.001). In contrast, CFPWV was not associated with NT-proBNP in controls. In patients with AF, the adjusted mean NT-proBNP level in the highest quartile of CFPWV (350 pg/ml; 95% CI 237 to 517 pg/ml) was fivefold higher than the lowest quartile (69 pg/ml; 95% CI 47 to 103 pg/ml) (p=0.001).</AbstractText>CFPWV is associated with NT-proBNP level in AF. Since elevated NT-proBNP is a marker of adverse cardiovascular outcomes, arterial stiffness may be associated with worse prognosis in patients with AF.</AbstractText> |
15,540 | Management of atrial fibrillation: focus on the role of dronedarone. | Dronedarone is an amiodarone derivative that was approved in the US in July 2009 to reduce the risk of cardiovascular hospitalization in patients with paroxysmal or persistent atrial fibrillation (AF), who are in sinus rhythm (SR), or who will be cardioverted.</AbstractText>This article reviews the pharmacology, adverse effects, and clinical evidence available to date on the use of dronedarone in the management of AF and its potential role in the emergency department setting.</AbstractText>In the EURIDIS and ADONIS studies evaluating the efficacy of dronedarone in maintaining SR, dronedarone significantly reduced the risk of recurrence of AF compared to placebo, by 22% and 27%, respectively. The ERATO study examined the ability of dronedarone to control ventricular rate in permanent AF. The DIONYSOS study demonstrated that recurrences of AF were more frequent with dronedarone. However, discontinuation of therapy due to intolerance was more frequent with amiodarone. Furthermore, the ATHENA study demonstrated that dronedarone reduced mortality and cardiovascular hospitalization by 24% (P < 0.05) in patients in SR but with other associated risks and a history of AF. However, the ANDROMEDA study, evaluating the use of dronedarone in patients with recent decompensated heart failure, and the PALLAS study, evaluating the use of dronedarone in patients with chronic AF, were both terminated prematurely due to a trend toward an increased risk of cardiovascular events.</AbstractText>Dronedarone has been demonstrated to be effective in reducing the incidence of AF recurrence. It appears to be less effective but better tolerated than amiodarone. Dronedarone appears to have a low proarrhythmic risk and is the first anti-arrhythmic that has been demonstrated to reduce cardiovascular mortality and cardiovascular hospitalization in clinically stable patients with other risk factors for recurrent AF. Therefore, dronedarone can be recommended as an anti-arrhythmic of choice in clinically stable patients for maintaining SR. If dronedarone is to be used in a patient with chronic stable heart failure, the patient must be monitored closely for any worsening of heart failure symptoms. The drug must be discontinued should the heart failure symptoms worsen.</AbstractText> |
15,541 | [Management of side-effects of targeted therapies in renal cancer: cardiovascular side-effects]. | Several types of cardiovascular complications can occur during treatment with targeted therapies: heart failure, QTc lengthening, arterial and venous thrombosis. A clinical examination, ECG and cardiac ultrasound are essential before starting treatment with targeted therapy. Patients with no medical history, who are asymptomatic with a normal ECG and a left ventricular ejection fraction (LVEF) greater than 50% can begin molecular targeted therapy (MTT). Patients must be assessed by a cardiologist before the introduction of MTT if they have a history of ischemic or valvular heart disease, heart failure, atrial fibrillation, stroke, transient ischemic attack, or ECG anomalies (Q wave, supraventricular arrhythmia, QT greater than 500ms), or LVEF less than 50%. In patients who are symptomatic (dyspnoea, angina, syncope, embolism etc.) and/or present with a modification to the ECG or alteration to the LVEF, MTT must be stopped and reassessment by a cardiologist is indicated. The restarting of MTT following a cardiovascular complication must be subject to a multidisciplinary discussion taking into account the severity of the cardiac event, its reversibility with cardiac treatment, life expectancy of the patient as well as the expected efficacy of the drug. |
15,542 | Life-threatening Takotsubo Cardiomyopathy. | To report a case of seizure-induced takotsubo cardiomyopathy with rare etiology and rarer complications.</AbstractText>A 50-year-old woman had multiple epileptic seizures and later developed acute heart failure complicated by ventricular fibrillation and shock. A two-dimensional echocardiogram revealed apical ballooning of the left ventricle resembling a takotsubo (a Japanese fisherman's pot used to trap octopi). The apex was also hypokinetic.</AbstractText>The hemodynamic abnormalities normalized with defibrillation, assisted ventilation, inotropic support, and pressor agents. More importantly, the apical ballooning deformity and systolic dysfunction reversed. The echocardiogram normalized three months later. A nuclear treadmill stress test was negative for ischemia.</AbstractText>Apical ballooning of the left ventricle and hypokinesis are typical echocardiographic features in takotsubo cardiomyopathy, a stress-induced heart disease. It may follow severe emotional, physical, and neurologic stressors, in our rare case, grand mal seizures (0.2 % of all takotsubo disease patients). Also rare are life-threatening complications. Based on these observations, in a case with severe stress followed by acute heart failure, takotsubo cardiomyopathy should be a major diagnostic consideration. The dramatic initial triggering event, in our case an epileptic seizure, should not mask the possibility of coexisting takotsubo cardiomyopathy. Awareness of this disease, anticipation of complications, and two-dimensional echocardiography will help channel the management in the right direction.</AbstractText> |
15,543 | Induction of therapeutic hypothermia requires modulation of thermoregulatory defenses. | Hypothermia has been linked to beneficial neurologic outcomes in different clinical situations and its therapeutic value is considered important. For example, in asphyctic neonates and in patients with out-of-hospital cardiac arrest (with ventricular fibrillation as the initial cardiac rhythm), rapid installation of hypothermia has been reported to add substantial therapeutic benefits over nonthermal standard treatments. Yet, in other groups of patients in which the application of therapeutic hypothermia may be applied with clinical benefits, the optimization of therapy remains less straightforward, as the body possesses vigorous defense mechanisms to protect it from inducing hypothermia, that is, especially in conscious patients and/or in those in which the hypothalamus remains intact, such as stroke patients or patients who suffer a myocardial infarction or spinal cord injury. This overview summarizes the body's primary reactions to hypothermia and the defense mechanisms available or evoked. Then, clinically applicable ways to overcome these forceful cold defenses of the body are described to ensure both an optimal induction process for therapeutic hypothermia and maximal subjective comfort for these conscious patients. |
15,544 | Use of therapeutic hypothermia in postcardiac arrest patients by emergency departments. | Since 2003, resuscitation guidelines have recommended the use of induced hypothermia as a therapy for patients who achieve return of spontaneous circulation after cardiac arrest from ventricular fibrillation. The aim of this study was to survey emergency physicians across the United States on their use of therapeutic hypothermia (TH) after cardiac arrest. An 18-question survey was e-mailed to a sample of emergency physicians. Fifty-eight respondents completed the survey. Most (71%) were associated with an emergency medicine residency training program. Annual census ranged from 12,000 to >170,000 visits. TH is used by the majority (69%) of respondents, 79% of which report the presence of a formal institutional protocol. The majority of respondents use TH in arrest rhythms including but not limited to ventricular fibrillation, and 21% begin the process in the prehospital setting. To induce hypothermia, a majority of respondents use commercial cooling products. The average time to target temperature was 95 minutes. The majority of respondents report a goal temperature between 32°C and 34°C. A shivering protocol is used by 76% of respondents, and as a first line medication, 46% use benzodiazepines. For those who do not use TH or do not have a protocol in place, the reasons cited include "too expensive," "too difficult to implement," and "not enough science to warrant it." In this sample of practicing emergency physicians, TH after cardiac arrest is not being used as described in the original literature. Although awareness and implementation of TH have increased, there appears to be a wide variation in the application of this therapy. |
15,545 | The use of hypothermia therapy in cardiac arrest survivors. | The annual incidence of out-of-hospital cardiac arrests in the United States is ∼350,000-450,000 per year. The prognosis for cardiac arrest survivors remains extremely poor. Therapeutic hypothermia (TH) is the only therapy proven to improve survival and neurological outcome in these patients. This article discusses the pathophysiology of neurological injury in cardiac arrest survivors and states the presumed mechanisms by which TH mitigates brain injury in these patients. It reviews the contraindications to the use of this therapy, methods of cooling, and phases of TH and elaborates on the intensive care unit management of TH. The use of TH in ventricular fibrillation survivors has become the standard of care and continues to evolve in its application as an essential therapy in cardiac arrest patients. |
15,546 | Radiofrequency ablation for treatment of atrial fibrillation. | Atrial Fibrillation (AF) is the most common cardiac arrhythmia which represents a major public health problem. The main purpose of this research is to evaluate the Radiofrequency (RF) ablation effects in the patients with chronic AF scheduled for cardiac surgery because of different heart diseases.</AbstractText>The descriptive and prospective study was conducted on 60 patients with AF scheduled for surgery along with RF ablation. The data were collected by questionnaire and included: patients' age, sex, NYHA class, operation type, past medical history, type and cause of valvular heart disease, preoperative ECG (electrocardiogram), duration of surgery, clamping time, cardiopulmonary bypass, and RF ablation time. RF ablation was followed by the main operation. The follow up examination, ECG, and echocardiography were performed 3 and 6 months after operation.</AbstractText>The mean age of patients was 48±10 years (18-71 years). Forty one patients had permanent AF and 19 had the persistent AF. The left ventricular ejection fraction was 48.27±9.75 percent before operation, and reached to 56.27±7.87 percent after the surgery (P<0.001). The mean NYHA class before the surgery was 2.83±0.68 which decreased to 1.34±0.46 6 months after the surgery with RF ablation (P<0.001). One patient (1.6%) died after surgery. Complete relief and freedom from AF recurrence was observed in 70% of patients in the mean follow up in 7 months after the surgery. The sinus rhythm with efficient atrial contraction was established in 100% of discharged patients.</AbstractText>RF ablation is an effective procedure to cure atrial fibrillation in patients undergoing cardiac surgeries.</AbstractText> |
15,547 | Near Field Communication-based telemonitoring with integrated ECG recordings. | Telemonitoring of vital signs is an established option in treatment of patients with chronic heart failure (CHF). In order to allow for early detection of atrial fibrillation (AF) which is highly prevalent in the CHF population telemonitoring programs should include electrocardiogram (ECG) signals. It was therefore the aim to extend our current home monitoring system based on mobile phones and Near Field Communication technology (NFC) to enable patients acquiring their ECG signals autonomously in an easy-to-use way.</AbstractText>We prototypically developed a sensing device for the concurrent acquisition of blood pressure and ECG signals. The design of the device equipped with NFC technology and Bluetooth allowed for intuitive interaction with a mobile phone based patient terminal. This ECG monitoring system was evaluated in the course of a clinical pilot trial to assess the system's technical feasibility, usability and patient's adherence to twice daily usage.</AbstractText>21 patients (4f, 54 ± 14 years) suffering from CHF were included in the study and were asked to transmit two ECG recordings per day via the telemonitoring system autonomously over a monitoring period of seven days. One patient dropped out from the study. 211 data sets were transmitted over a cumulative monitoring period of 140 days (overall adherence rate 82.2%). 55% and 8% of the transmitted ECG signals were sufficient for ventricular and atrial rhythm assessment, respectively.</AbstractText>Although ECG signal quality has to be improved for better AF detection the developed communication design of joining Bluetooth and NFC technology in our telemonitoring system allows for ambulatory ECG acquisition with high adherence rates and system usability in heart failure patients.</AbstractText> |
15,548 | [Differences in atrial remodelling between right and left atria in patients with chronic atrial fibrillation]. | Atrial fibrillation starts in the left atrium and from there the activity invades the atrial tissues and causes an inhomogeneous shortening the duration of atrial action potential duration and refractoriness. The purpose of this study was to compare the voltage-dependent potassium currents in human cells isolated from the right and left atria and to determine whether electrical remodeling produced by chronic atrial fibrillation (CAF) differentially affects voltage-dependent potassium currents involved in atrial repolarization in each atrium as compared to sinus rhythm (SR). The currents were recorded using the whole-cell configuration of the patch-clamp technique. We found that in atrial cardiomyocytes of patients both in SR and in CAF there are three types of cells according to their main voltage-dependent repolarizing potassium current: the Ca(2+)-independent 4-aminopyridine sensitive component of the transient outward current (I(to1)) and the ultrarapid (I(Kur)), rapid (I(Kr)) and slow (I(Ks)) components of the delayed rectifier current. CAF differentially modified the proportion of these 3 types of cells on each atrium: CAF reduced the I(to1) more markedly in the left than in the right atria, while I(Kur) was more markedly reduced in the right than in the left atria. Interestingly, in both atria, CAF markedly increased the I(Ks). This increase was enhanced by isoproterenol and suppressed by atenolol. These changes produce a non-uniform shortening of atrial repolarization that facilitates the reentry of the cardiac impulse and the perpetuation of the arrhythmia. |
15,549 | Cardiac tamponade in acute pancreatitis. | A 47-year-old man presented with severe acute pancreatitis. On hospitalisation day 8, the patient became hypotensive and developed new-onset atrial fibrillation. Echocardiography showed significant pericardial effusion with right ventricular collapse. A pericardial window was made and the effusion drained. There was rapid clinical improvement following the procedure. |
15,550 | Therapeutic hypothermia after cardiac arrest in a 66-year-old man. | Hypoxic-ischaemic brain injury is an important cause of morbidity and mortality following both in- and out-of-hospital cardiac arrest. Despite significant advances in critical care the only intervention proven to increase survival rates after cardiac arrest is mild hypothermia. The authors present a case describing the use of therapeutic hypothermia after ventricular fibrillation cardiac arrest, including its indications and contra-indications, and the techniques that can be used to induce it. |
15,551 | A Cellular Automata-based Model for Simulating Restitution Property in a Single Heart Cell. | Ventricular fibrillation is the cause of the most sudden mortalities. Restitution is one of the specific properties of ventricular cell. The recent findings have clearly proved the correlation between the slope of restitution curve with ventricular fibrillation. This; therefore, mandates the modeling of cellular restitution to gain high importance. A cellular automaton is a powerful tool for simulating complex phenomena in a simple language. A cellular automaton is a lattice of cells where the behavior of each cell is determined by the behavior of its neighboring cells as well as the automata rule. In this paper, a simple model is depicted for the simulation of the property of restitution in a single cardiac cell using cellular automata. At first, two state variables; action potential and recovery are introduced in the automata model. In second, automata rule is determined and then recovery variable is defined in such a way so that the restitution is developed. In order to evaluate the proposed model, the generated restitution curve in our study is compared with the restitution curves from the experimental findings of valid sources. Our findings indicate that the presented model is not only capable of simulating restitution in cardiac cell, but also possesses the capability of regulating the restitution curve. |
15,552 | [Metabolic syndrome impact on arrhythmias genesis in elderly women]. | The article discusses the data of a study aimed at the impact of the metabolic syndrome on arrhythmias in elderly women. Analysis of the data showed that supraventricular arrhythmias were detected in most part of elderly women, ventricular arrhythmias a few less. The share of prognostically unfavorable arrhythmias is small, but they develop linked to the metabolic changes, and dangerous ventricular arrhythmias and atrial fibrillation develop more often in patients with metabolic syndrome. |
15,553 | Earlier Hypothermia Attainment is Associated with Improved Outcomes after Cardiac Arrest. | Therapeutic hypothermia (TH, 32-34ºC) reduces mortality and improves neurologic outcomes after ventricular fibrillation cardiac arrest (CA). The relationship between time to achieve TH and outcomes remains undefined. We hypothesized that a shorter interval from CA to achieve TH would be associated with improved neurologic outcome.</AbstractText>We retrospectively reviewed subjects within or out-of-hospital CA treated with TH between November 2006 and April 2009 at our institution. The time to target temperature was defined as the interval between witnessed CA and first measurement of hypothermia (≤ 34 ºC) and further categorized as early (< 6 hours) or delayed (> 6 hours). Outcomes were assessed at the time of death or discharge using Cerebral Performance Category Score (CPC); good outcome was defined as CPC ≤ 2. Fisher's Exact test was used to assess the univariate relationship between time to TH and outcome.</AbstractText>26 patients achieved TH after in-hospital (39%) and out-of-hospital (61%) CA. Five patients (5/26) reached early target temperature; 80% (4/5) of those had a good neurological outcome. 24% (5/21) of subjects with delayed target temperature achieved a good neurological outcome. The univariate relationship between time to target temperature and neurological outcome was statistically significant (p=0.034).</AbstractText>Attaining TH within 6 hours of in or out-of-hospital CA was associated with a greater likelihood of a good neurological outcome at discharge. Time from CA to achieved TH should be included as a clinically important covariate in future studies of predictors of outcome after CA.</AbstractText> |
15,554 | Targeted temperature management in critical care: a report and recommendations from five professional societies. | Representatives of five international critical care societies convened topic specialists and a nonexpert jury to review, assess, and report on studies of targeted temperature management and to provide clinical recommendations.</AbstractText>Questions were allocated to experts who reviewed their areas, made formal presentations, and responded to questions. Jurors also performed independent searches. Sources used for consensus derived exclusively from peer-reviewed reports of human and animal studies.</AbstractText>Question-specific studies were selected from literature searches; jurors independently determined the relevance of each study included in the synthesis.</AbstractText>1) The jury opines that the term "targeted temperature management" replace "therapeutic hypothermia." 2) The jury opines that descriptors (e.g., "mild") be replaced with explicit targeted temperature management profiles. 3) The jury opines that each report of a targeted temperature management trial enumerate the physiologic effects anticipated by the investigators and actually observed and/or measured in subjects in each arm of the trial as a strategy for increasing knowledge of the dose/duration/response characteristics of temperature management. This enumeration should be kept separate from the body of the report, be organized by body systems, and be made without assertions about the impact of any specific effect on the clinical outcome. 4) The jury STRONGLY RECOMMENDS targeted temperature management to a target of 32°C-34°C as the preferred treatment (vs. unstructured temperature management) of out-of-hospital adult cardiac arrest victims with a first registered electrocardiography rhythm of ventricular fibrillation or pulseless ventricular tachycardia and still unconscious after restoration of spontaneous circulation (strong recommendation, moderate quality of evidence). 5) The jury WEAKLY RECOMMENDS the use of targeted temperature management to 33°C-35.5°C (vs. less structured management) in the treatment of term newborns who sustained asphyxia and exhibit acidosis and/or encephalopathy (weak recommendation, moderate quality of evidence).</AbstractText> |
15,555 | Loss of anti-arrhythmic effect of vagal nerve stimulation on ischemia-induced ventricular tachyarrhythmia in aged rats. | Reduced vagal activity is associated with increased risk for life-threatening arrhythmia during myocardial ischemia (MI); conversely, the increase in vagal tone may provide protective effect against ventricular arrhythmias. In fact, vagal nerve stimulation (VNS) exerted an anti-arrhythmic effect by preserving connexin 43 (Cx43), a gap junction protein in ventricles, in a rat model of MI. We investigated the effects of VNS on ventricular tachyarrhythmia during acute MI and the expression of Cx43 in aged rats. Both adult (3-4 months) and aged (≥ 24 months) male rats were subjected to ischemia of 30 min. VNS was applied before ischemia either alone or in combination with atropine (0.5 mg/kg) or carbenoxolone, a gap junction inhibitor (10 mg/kg). During the 30-min ischemia, the incidence of ventricular tachycardia (VT) or ventricular fibrillation (VF) was higher in aged rats compared with adult rats. VNS significantly suppressed VT and VF in adult rats and these effects were eliminated by atropine or carbenoxolone. In contrast, VNS did not suppress VT and VF in the aged rats. Moreover, ischemia did not change the expression levels of total Cx43 protein in adult and aged rat ventricles. However, the expression level of total Cx43 protein was two times lower in sham-operated aged rats than that in sham-operated adult rats. Thus, in aged rats, loss of anti-arrhythmic effect of VNS is associated with reduced expression of Cx43 protein. These findings suggest that Cx43 may be an important target for inhibiting ischemia-induced VT in adult patients but not in aged patients. |
15,556 | Perioperative cardiac events in endovascular repair of complex aortic aneurysms and association with preoperative studies. | Endovascular repair of complex aortic aneurysms (CAAs) can be performed in high-risk individuals, yet is still associated with significant morbidity, including spinal cord ischemia, cardiac complications, and death. This analysis was undertaken to better define the cardiac risk for CAA.</AbstractText>A prospective database of patients undergoing thoracoabdominal or juxtarenal aortic aneurysm repair with branched and fenestrated endografts was used to retrospectively determine the number of cardiac events, defined as myocardial infarction (MI), atrial fibrillation (AF), and ventricular arrhythmia (VA), that occurred ≤ 30 days of surgery. Postoperative serial troponin measurements were performed in 266 patients. Any additional available cardiac information, including preoperative echocardiography, physiologic stress tests, and history of cardiac disease, was obtained from medical records. The efficacy of preoperative stress testing and the association of various echo parameters were evaluated in the context of cardiac outcomes using univariable and multivariable logistic regression models.</AbstractText>Between August 2001 and December 2007, 395 patients underwent endovascular repair of a thoracoabdominal or juxtarenal aortic aneurysm. The incidence of AF, VA, and 30-day cardiac-related death was 9%, 3%, and 2%, respectively. Overall 30-day mortality was 6%. Univariable analysis showed the presence of mitral annulus calcification was associated with MI (odds ratio [OR], 3.5; 95% confidence interval [CI], 0.9-13.8; P = .07). Left atrium cavity area, ejection fraction, left ventricle mass, and left ventricular mass index were univariably associated with the presence of VA. Multivariable analysis showed only the left atrium cavity area was independently associated with VA (OR, 1.2; 95% CI, 1.0-1.5; P = .07). Stress test was done in 179 patients. Negative stress test results occurred in 152 (85%), of whom 9 (6%) sustained an MI during the 30-day perioperative course. MI occurred in 2 of the 27 patients (7%) who had a positive stress test result.</AbstractText>Endovascular repair of CAA can be performed in high-risk individuals but is associated with significant cardiac risk. It remains difficult to risk stratify patients using preoperative stress testing. Echo evaluation may help to identify patients who may be more likely to develop ventricular arrhythmias in the postoperative period and thus warrant closer monitoring. Postoperative troponin monitoring of all patients undergoing repair of CAA is warranted given the overall risk of MI.</AbstractText>Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
15,557 | B-type natriuretic peptide levels predict functional capacity in postcardiac surgery patients. | Plasma levels of B-type natriuretic peptide (BNP) are often increased in postcardiac surgery patients. The six-minute walking test (6MWT) is useful to assess functional capacity in postcardiac surgery patients. The aim of this study was to determine whether BNP levels are associated with exercise capacity evaluated by 6MWT in patients after cardiac surgery.</AbstractText>Plasma BNP was measured in 101 consecutive patients referred to our center 8 ± 5 days after cardiac surgery who underwent echocardiography and 6MWT. We considered age, sex, diabetes, renal insufficiency, anemia, chronic obstructive pulmonary disease, hypertension, atrial fibrillation, beta-blocker therapy, left ventricular ejection fraction (LVEF), E/E', indexed left atrial volume (iLAV), type of surgery, and plasma BNP levels as potential predictors of reduced performance at 6MWT evaluated as percentages of the predicted values calculated according to the regression equation obtained in healthy individuals.</AbstractText>The mean distance walked at 6MWT was 325 ± 100 m corresponding to 65 ± 20% of the predicted values. This was independent of the LVEF, E/E' or iLAV. Female patients or patients with atrial fibrillation had a reduced performance compared with male patients or patients with sinus rhythm (52 ± 19 vs. 70 ± 19%, P < 0.001; 50 ± 19 vs. 66 ± 19%, P = 0.017, respectively). BNP levels were inversely related to the performance at 6MWT (Pearson's correlation coefficient = -0.25, P = 0.010). At multivariate analysis, female sex (P < 0.001), atrial fibrillation (P = 0.031), and BNP levels (P = 0.040) remained the only independent predictive factors for reduced exercise capacity.</AbstractText>The increase in BNP levels in postcardiac surgery patients is associated with reduced exercise capacity.</AbstractText> |
15,558 | Congestive heart failure in two pet rabbits. | This case report describes congestive heart failure with pleural effusion in two middle-aged, pet house rabbits. Both had a history of acute onset dyspnoea, weakness and weight loss. Bi-atrial enlargement was seen on echocardiography in both rabbits. One rabbit had atrial fibrillation and ventricular premature complexes identified on electrocardiography. There was a radiographically evident pleural effusion in both rabbits and thoracocentesis was undertaken in one rabbit. These findings were confirmed on post-mortem examination. The aetiology for the underlying heart disease was not found, but the potential types of cardiomyopathies are discussed. |
15,559 | Predictors of atrial fibrillation following coronary artery bypass surgery. | New-onset atrial fibrillation is the most common form of rhythm disturbance following coronary artery bypass grafting surgery (CABG). It is still unclear which factors have a significant impact on its occurrence after this procedure. The aim of this study was to evaluate clinical predictors of postoperative atrial fibrillation (POAF) after myocardial revascularization.</AbstractText><AbstractText Label="MATERIAL/METHODS" NlmCategory="METHODS">We performed a retrospective analysis of 322 patients who underwent the first CABG operation without baseline atrial fibrillation. All subjects underwent laboratory blood tests, echocardiography and selective coronarography with ventriculography. Patients were continuously electrocardiographically monitored during the first 48-72 h after the operation for the occurrence of POAF.</AbstractText>POAF was diagnosed in 72 (22.4%) of the patients. Multivariate logistic regression analysis was used to identify the following independent clinical predictors of POAF: age≥65 years (OR 1.78; 95%CI: 1.06-2.76; p=0.043), hypertension (OR 1.97; 95%CI: 1.15-3.21; p=0.018), diabetes mellitus (OR 2.09; 95% CI: 1.31-5.33; p=0.010), obesity (OR 1.51; 95%CI: 1.03-3.87; p=0.031), hypercholesterolemia (OR 2.17, 95%CI: 1.05-4.25; p=0.027), leukocytosis (OR 2.32, 95%CI: 1.45-5.24; p=0.037), and left ventricular segmental kinetic disturbances (OR 3.01; 95%CI: 1.65-4.61, p<0.001).</AbstractText>This study demonstrates that advanced age, hypertension, diabetes, obesity, hypercholesterolemia, leukocytosis, and segmental kinetic disturbances of the left ventricle are powerful risk factors for the occurrence of POAF.</AbstractText> |
15,560 | Arterial wave reflection and subclinical left ventricular systolic dysfunction. | Increased arterial wave reflection is a predictor of cardiovascular events and has been hypothesized to be a cofactor in the pathophysiology of heart failure. Whether increased wave reflection is inversely associated with left-ventricular (LV) systolic function in individuals without heart failure is not clear.</AbstractText>Arterial wave reflection and LV systolic function were assessed in 301 participants from the Cardiovascular Abnormalities and Brain Lesions (CABL) study using two-dimensional echocardiography and applanation tonometry of the radial artery to derive central arterial waveform by a validated transfer function. Aortic augmentation index (AIx) and wasted energy index (WEi) were used as indices of wave reflection. LV systolic function was measured by LV ejection fraction (LVEF) and tissue Doppler imaging (TDI). Mitral annulus peak systolic velocity (Sm), peak longitudinal strain and strain rate were measured. Participants with history of coronary artery disease, atrial fibrillation, LVEF less than 50% or wall motion abnormalities were excluded.</AbstractText>Mean age of the study population was 68.3 ± 10.2 years (64.1% women, 65% hypertensive). LV systolic function by TDI was lower with increasing wave reflection, whereas LVEF was not. In multivariate analysis, TDI parameters of LV longitudinal systolic function were significantly and inversely correlated to AIx and WEi (P values from 0.05 to 0.002).</AbstractText>In a community cohort without heart failure and with normal LVEF, an increased arterial wave reflection was associated with subclinical reduction in LV systolic function assessed by novel TDI techniques. Further studies are needed to investigate the prognostic implications of this relationship.</AbstractText> |
15,561 | Does early surgical intervention improve left ventricular mass regression after mitral valve repair for leaflet prolapse? | Left ventricular hypertrophy is associated with adverse cardiovascular outcomes. It is unclear whether hypertrophy caused by severe chronic mitral regurgitation regresses after mitral valve repair and, if so, which factors promote reverse remodeling and influence its prognostic significance.</AbstractText>Between March 1995 and December 2005, 2589 patients had mitral valve repair. Five hundred thirty patients (346 of whom were male) underwent isolated repair for leaflet prolapse and had echocardiographic data available from which the left ventricular mass index could be calculated. Concomitant preoperative tricuspid valve regurgitation was more than mild in 95 (18%) patients. Those with preoperative atrial fibrillation and other cardiac pathologies necessitating intracardiac repair were not included.</AbstractText>Significant regression of left ventricular mass index occurred during the first 3 years (-28 g/m(2), P < .001) and was maintained during follow-up for more than 3 years (-26 g/m(2), P < .001). Higher preoperative left ventricular ejection fraction and greater preoperative left ventricular mass index independently predicted improved left ventricular mass index regression at 3 years. During follow-up of greater than 3 years, greater preoperative left ventricular mass index persisted in predicting improved mass regression (P < 0.001), and greater than mild preoperative tricuspid valve regurgitation was associated with less mass regression (P < .001). Late recovery of normal left ventricular ejection fraction was impaired in those with the greatest residual left ventricular mass; however, there was no difference in late symptoms or survival.</AbstractText>Performing mitral valve repair before a decrease in left ventricular ejection fraction and the development of significant secondary tricuspid valve regurgitation is associated with a greater likelihood of significant regression of left ventricular mass, possibly predicting improved recovery of normal left ventricular function after surgical intervention. These data provide additional support for early degenerative mitral valve repair.</AbstractText>Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
15,562 | Natriuretic peptide levels predict recurrence of atrial fibrillation after radiofrequency catheter ablation. | the presence of atrial fibrillation (AF) is related to increased levels of natriuretic peptides. In addition, increased natriuretic peptide levels are predictive of the development of AF. However, the role of natriuretic peptides to predict recurrence of AF after radiofrequency catheter ablation (RFCA) is controversial.</AbstractText>the study aimed to investigate the role of natriuretic peptides in the prediction of AF recurrence after RFCA for AF.</AbstractText>pre-procedural amino-terminal pro-atrial natriuretic peptide (NT-proANP) and amino-terminal-pro-B-type natriuretic peptide (NT-proBNP) plasma levels were determined in 87 patients undergoing RFCA for symptomatic drug-refractory AF. In addition, a comprehensive clinical and echocardiographic evaluation was performed at baseline. Left atrial volumes, left ventricular volumes, and function (systolic and diastolic) were assessed. During a 6-month follow-up period, AF recurrence was monitored and defined as any registration of AF on electrocardiogram or an episode of AF longer than 30 seconds on 24-hour Holter monitoring. The role of natriuretic peptide plasma levels to predict AF recurrence after RFCA was studied.</AbstractText>During follow-up, 66 patients (76%) maintained sinus rhythm, whereas 21 patients (24%) had AF recurrence. Patients with AF recurrence had higher baseline natriuretic peptide levels than patients who maintained sinus rhythm (NT-proANP 3.19 nmol/L [2.55-4.28] vs 2.52 nmol/L [1.69-3.55], P = .030; NT-proBNP 156.4 pg/mL [64.1-345.3] vs 84.6 pg/mL [43.3-142.7], P = .036). However, NT-proBNP was an independent predictor of AF recurrence, whereas NT-proANP was not. Moreover, NT-proBNP had an incremental value over echocardiographic characteristics to predict AF recurrence after RFCA.</AbstractText>baseline NT-proBNP plasma level is an independent predictor of AF recurrence after RFCA.</AbstractText> |
15,563 | MRI of the left atrium: predicting clinical outcomes in patients with atrial fibrillation. | Atrial fibrillation is a significant public health burden, with clinically, epidemiologically and economically significant repercussions. In the last decade, catheter ablation has provided an improvement in morbidity and quality of life, significantly reducing long-term healthcare costs and avoiding recurrences compared with drug therapy. Despite recent progress in techniques, current catheter ablation success rates fall short of expectations. Late gadolinium-enhancement cardiovascular MRI is a well-established tool to image the myocardium and, most specifically, the left atrium. Unique imaging protocols allow for left atrial structural remodeling and fibrosis assessment, which has been demonstrated to correlate with clinical outcomes after catheter ablation, assessment of the individual's risks of thromboembolic events, and effective imaging of patients with left atrial appendage thrombus. Late gadolinium-enhancement MRI aids in the individualized treatment of atrial fibrillation, stratifying recurrence risk and guiding specific ablation strategies. Real-time MRI offers significant safety and effectiveness profiles that would optimize the invasive treatment of atrial fibrillation. |
15,564 | Electrical storms in patients with an implantable cardioverter defibrillator. | In some patients with an implantable cardioverter defibrillator (ICD), multiple episodes of electrical storm (ES) can occur. We assessed the prevalence, features, and predictors of ES in patients with ICD.</AbstractText>Eighty-five patients with an ICD were analyzed. ES was defined as the occurrence of two or more ventricular tachyarrhythmias within 24 hours.</AbstractText>Twenty-six patients experienced at least one ES episode, and 16 patients experienced two or more ES episodes. The first ES occurred 209 ± 277 days after ICD implantation. In most ES cases, the index arrhythmia was ventricular tachycardia (65%). There were no obvious etiologic factors at the onset of most ES episodes (57%). More patients with a structurally normal heart (p = 0.043) or ventricular fibrillation (VF) as the index arrhythmia (p = 0.017) were in the ES-free group. Kaplan-Meier estimates and a log-rank test showed that patients with nonischemic dilated cardiomyopathy (DCMP) (log-rank test, p = 0.016) or with left ventricular ejection fraction < 35% (p = 0.032) were more likely to experience ES, and that patients with VF (p = 0.047) were less affected by ES. Cox proportional hazard regression analysis showed that nonischemic DCMP correlated with a greater probability of ES (hazard ratio, 3.71; 95% confidence interval, 1.16-11.85; p = 0.027).</AbstractText>ES is a common and recurrent event in patients with an ICD. Nonischemic DCMP is an independent predictor of ES. Patients with VF or with a structurally normal heart are less likely to experience ES.</AbstractText> |
15,565 | A clinical risk score for atrial fibrillation in a biracial prospective cohort (from the Atherosclerosis Risk in Communities [ARIC] study). | A risk score for atrial fibrillation (AF) has been developed by the Framingham Heart Study; however, the applicability of this risk score, derived using data from white patients, to predict new-onset AF in nonwhites is uncertain. Therefore, we developed a 10-year risk score for new-onset AF from risk factors commonly measured in clinical practice using 14,546 subjects from the Atherosclerosis Risk In Communities (ARIC) study, a prospective community-based cohort of blacks and whites in the United States. During 10 years of follow-up, 515 incident AF events occurred. The following variables were included in the AF risk score: age, race, height, smoking status, systolic blood pressure, hypertension medication use, precordial murmur, left ventricular hypertrophy, left atrial enlargement, diabetes, coronary heart disease, and heart failure. The area under the receiver operating characteristics curve (AUC) of a Cox regression model that included the previous variables was 0.78, suggesting moderately good discrimination. The point-based score developed from the coefficients in the Cox model had an AUC of 0.76. This clinical risk score for AF in the Atherosclerosis Risk In Communities cohort compared favorably with the Framingham Heart Study's AF (AUC 0.68), coronary heart disease (CHD) (AUC 0.63), and hard CHD (AUC 0.59) risk scores and the Atherosclerosis Risk In Communities CHD risk score (AUC 0.58). In conclusion, we have developed a risk score for AF and have shown that the different pathophysiologies of AF and CHD limit the usefulness of a CHD risk score in identifying subjects at greater risk of AF. |
15,566 | Vernakalant: a new drug to treat patients with acute onset atrial fibrillation. | Vernakalant is a new antiarrhythmic drug that acts selectively in the atrium, targeting atrial specific channels: the Kv1.5 channel which carries IK(ur), and the Kir3.1/3.4 channel which carries IK(Ach). Vernakalant can also work to block Ito, late Ina, with minor blockade of IKr currents. Vernakalant is available in both intravenous and oral forms. In phase II and III trials, intravenous vernakalant has been shown to be effective in terminating acute onset atrial fibrillation whose duration is >3 hours and <7 days (∼50% efficiency vs. 10% for placebo). It does not appear to be effective for atrial fibrillation whose duration is >7 days, nor does it appear to be effective for atrial flutter. Studies with oral vernakalant have been designed to evaluate its efficacy and safety in the prevention of atrial fibrillation recurrence. Studies to date have shown that 51% of patients were able to maintain sinus rhythm after 90 days of using oral vernakalant 50 mg/kg twice daily compared with 37% of patients receiving placebo. Vernakalant appears to be a safe drug to use, with the most common side-effects being dysgeusia, sneezing, paresthesias, nausea, and hypotension. In the clinical trials, there were minimal drug-induced ventricular arrhythmias observed. |
15,567 | Oral anticoagulation with warfarin for patients with left ventricular systolic dysfunction. | Patients with systolic heart failure are thought to be at increased risk for thromboembolic events. Although these patients may have increased hypercoaguable markers, the incidence of stroke is thought to be relatively low. Still, oral anticoagulation with warfarin is sometimes prescribed in these patients to prevent potential thromboembolic events. Current guidelines do not recommend warfarin use in patients with systolic heart failure unless indicated for other cardiovascular conditions. Several studies that have attempted to address this controversy have, as a whole, demonstrated that the rates of thromboembolic events in patients with systolic heart failure taking warfarin are similar to those in patients taking placebo, basically showing no additional protective benefit of warfarin. In addition, these studies have shown an increased risk of bleeding with warfarin. However, these trials are of poor quality to date. The 4 post hoc analyses in this article had warfarin added at the investigators' discretion and included patients with indications for warfarin, such as atrial fibrillation. The 3 randomized trials in this article did not attain enrollment numbers to reach any calculated power and were stopped early; thus, they were unable to detect a difference. Since warfarin has shown benefit in patients with atrial fibrillation and in mechanical heart valves to decrease the risk of thromboembolism, it might stand to reason that warfarin would have the same benefit in systolic heart failure patients without the above indications. However, given the current available data, warfarin is not supported in patients with systolic heart failure in the absence of an indication for this drug. |
15,568 | Left ventricular noncompaction. | Left ventricular noncompaction is a rare cardiomyopathy characterized by prominent ventricular hypertrabeculation. Here, we discuss the case of a 30-year-old man who presented with rapidly conducted atrial fibrillation. The images we present demonstrate appearances characteristic of this cardiomyopathy, with prominent trabeculations and an end-diastolic noncompacted to compacted myocardial thickness ratio of more than 2 noted on echocardiography and magnetic resonance imaging. |
15,569 | The role of catheter ablation for ventricular tachycardia in patients with ischemic heart disease. | Catheter ablation has evolved remarkably over the last 2 decades, bringing nonpharmacologic therapy to complex arrhythmias like atrial fibrillation and scar-related ventricular tachycardia. As our therapeutic options have increased for patients with ventricular tachycardia, choosing the right therapy for the right patient has become more complex. Ablation carries acute and perhaps longer-term procedural risk and variable success, whereas drug therapy likewise is limited by both side-effects and efficacy.</AbstractText>Early randomized trials of catheter ablation for ventricular tachycardia and multicenter experiences have recently been published, and further studies are underway to define the appropriate application of this therapy. Randomized trials have demonstrated that catheter ablation can reduce ventricular tachycardia episodes with relatively low risk. Multicenter experience has demonstrated a moderate risk of serious procedural adverse events in this very sick population, but ablation has never been compared directly with antiarrhythmic drug therapy.</AbstractText>There is still little evidence to clarify the relative merits of antiarrhythmic drug therapy in comparison with ablation. The optimal role of either therapy will remain uncertain until the completion of trials currently in progress. Until further evidence is available, most clinicians advocate first-line antiarrhythmic drug therapy, and reserve catheter ablation for when this fails or is not tolerated.</AbstractText> |
15,570 | Impact of prehospital delay in treatment seeking on in-hospital complications after acute myocardial infarction. | Rapid arrival to the hospital for treatment of acute myocardial infarction (AMI) improves long-term outcomes. Whether prehospital delay time is associated with short-term, in-hospital complications remains unknown.</AbstractText>The purpose of this study was to evaluate the fit of a theoretical model where prehospital delay time was indirectly associated with hospital length of stay through in-hospital complications after AMI considering simultaneously for demographic, clinical, and psychosocial factors using structural equation modeling.</AbstractText>Acute myocardial infarction patients (N = 536; 66% men; mean age, 62 [SD, 14] years) were enrolled in this prospective study. Demographic and clinical data were obtained by patient interview and medical record review. After patient discharge, complications were abstracted from the medical record.</AbstractText>Prehospital delay, admission Killip class, and in-hospital anxiety were the best predictors of in-hospital complications, including recurrent ischemia, reinfarction, sustained ventricular tachycardia or fibrillation, and cardiac death, after AMI (P = .019). The occurrence of in-hospital complications was related to length of stay in the hospital (P < .001).</AbstractText>Prehospital delay in promptly seeking hospital treatment for AMI symptoms, together with state anxiety and worse heart failure, was associated with the occurrence of more frequent serious complications during the hospital stay. It is essential that research and clinical efforts focus on the complex and dynamic issue of improving prehospital delay in AMI patients.</AbstractText> |
15,571 | Treatment of heart failure with normal ejection fraction. | Heart failure (HF) is a major cause of mortality and morbidity and one of the most frequent reasons for hospital admission in the United States and Europe. Currently, more than 50% of HF patients have a normal (N) left ventricular (LV) ejection fraction (EF) (LVEF >50%). The main pathophysiologic processes involved in HFNEF are increased LV stiffness and abnormal relaxation, resulting in impaired LV filling. Hypertension and myocardial ischemia are the most common causes of HFNEF. Precipitating factors include volume overload, tachycardia, physical exercise, systemic stressors (such as fever and infection), arrhythmia, increased salt intake, and use of nonsteroidal anti-inflammatory drugs. There is little evidence to guide treatment, as previously HFNEF patients have been excluded from clinical trials on the basis of a normal LVEF. Survival improved over time in patients with reduced (R) EF (HFREF) (LVEF <40%), reflecting the beneficial effects of treatment in this phenotype. However, survival did not improve for HFNEF patients. The approach to the treatment of HFNEF patients should focus on reducing LV filling pressure, controlling hypertension, modifying ischemia, and improving LV relaxation. Therefore, diuretics are suitable for HFNEF patients to reduce ventricular filling pressure. Hypertension can be treated by using multiple agents if necessary. Drugs of particular interest and recommended to treat hypertension are calcium channel blockers (CCBs) and antagonists of the renin-angiotensin-aldosterone system, such as angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and aldosterone antagonists. Ischemic heart disease can be treated with antiplatelet therapy, anticoagulants, and β-blockers. Heart rate control in atrial fibrillation can be achieved with β-blockers and digoxin. Finally, ACE inhibitors and ARBs could potentially decrease LV hypertrophy in hypertensive patients with HFNEF. |
15,572 | Genetic predisposition to sudden cardiac death. | Sudden cardiac death (SCD) is a major public health burden, and evidence from family history and from molecular studies on inherited arrhythmogenic syndromes indicates that genetic factors are important contributors to the risk of SCD. This review discusses recent advances on the genetic predisposition to SCD, with a specific focus on primary ventricular fibrillation and channelopathies.</AbstractText>Coronary artery disease is the major determinant of SCD, and its predisposing genetic background is complex. Very recently, a first genome-wide association study on primary ventricular fibrillation was published but the results are not conclusive and further studies with greater numbers are needed. Among channelopathies, long QT syndrome and Brugada syndrome are those in which more significant advances have been reported in the last year. Of note is the recently described early repolarization syndrome and the proposed classification of J wave syndromes. Revision of current guidelines for autopsy investigation has introduced molecular autopsy as a standard requirement for adequate assessment of SCD.</AbstractText>Interesting data on the genetic basis of sudden cardiac death have been published in the past year, and, whereas in the field of channelopathies research findings have been partially recognized by current guidelines and translated into clinical practice, in the field of coronary artery disease further advances are still needed.</AbstractText> |
15,573 | A new defibrillator mode to reduce chest compression interruptions for health care professionals and lay rescuers: a pilot study in manikins. | Chest compression interruptions are detrimental during the resuscitation of cardiac arrest patients, especially immediately prior to shock delivery.</AbstractText>To evaluate the effect of use of a new defibrillator technology, which filters compression-induced artifact and provides reliable rhythm analysis with automatic defibrillator charging during chest compressions, on preshock chest compression interruption.</AbstractText>Thirty subjects (20 basic life support [BLS]; 10 advanced life support [ALS]) worked in pairs to perform two randomly ordered simulated cardiac resuscitations with the defibrillator operating in either standard mode (ALS = manual; BLS = automated external defibrillator [AED]) or the new Analysis and Charging during CPR (AC-CPR) mode. During each resuscitation simulation, rescuers switched roles as chest compressor and defibrillator operator every two segments of CPR (one segment = 2 minutes of chest compressions, rhythm analysis, and shock delivery, if appropriate), for eight total segments. The participants rested ≥30 minutes between trials and received brief AC-CPR training (BLS = 30 seconds; ALS = 5 minutes). Heart rate and perceived exertion were measured with pulse oximetry and the Borg scale, respectively.</AbstractText>Mean (± standard deviation) preshock chest compression pause time was considerably shorter in each CPR segment with AC-CPR versus standard defibrillator operation (2.13 ± 0.99 sec vs. 10.93 ± 1.33, p < 0.0001), demonstrating effective use of AC-CPR with minimal training. Despite reduced chest compression interruption with AC-CPR, rescuer fatigue and perceived exertion did not differ in any CPR segment with standard defibrillator operation versus AC-CPR (p = 0.2-1.0).</AbstractText>Preshock pause time is reduced by 80% utilizing a novel technology that employs automated analysis and charging during chest compression. Although chest compression pause time is reduced with the use of the new technology, participants do not excessively fatigue.</AbstractText> |
15,574 | Management of arrhythmias in patients with tetralogy of Fallot. | Patients with tetralogy of Fallot are subject to arrhythmic sequelae that substantially impact morbidity and mortality. This review focuses on recent advances in our understanding of the prevalence and types of arrhythmias encountered. Diagnostic and prognostic tools are considered and therapeutic options discussed.</AbstractText>Multicenter studies have characterized the arrhythmia burden, assessed the impact of implantable cardioverter-defibrillators, and generated a risk score for primary prevention. Left ventricular hemodynamics are increasingly recognized as important contributors to risk for sudden death. Arrhythmia circuits have been characterized, and the impact of pulmonary valve replacement on sudden death has been further questioned. Recent studies cast doubt on the value of right ventricular pacing alone for cardiac resynchronization and provide a rationale for biventricular pacing.</AbstractText>Supraventricular arrhythmias exceed ventricular arrhythmias in prevalence, as atrial fibrillation increases with the aging population. Sudden death is the leading cause of late mortality, although therapeutic advances may alter this profile. Combinations of factors should be considered in risk stratification schemes to select appropriate implantable cardioverter-defibrillator candidates. The role of concomitant intraoperative ablation during pulmonary valve replacement surgery remains to be defined. Cardiac resynchronization therapy, particularly biventricular pacing, offers promise, but requires careful study before widespread implementation.</AbstractText> |
15,575 | Statin therapy significantly reduces risk of ventricular tachyarrhythmias in patients with an implantable cardioverter defibrillator. | A few observational studies have shown the protective effect of statins on preventing ventricular tachycardia/ventricular fibrillation (VT/VF). However, the disparate study results prompt further exploration of this concept. We performed a meta-analysis to assess whether statin therapy is associated with a decrease in the incidence or recurrence of VT/VF in patients with an implantable cardioverter-defibrillator (ICD).The MEDLINE(®) and Cochrane databases were searched from 1980 to July 2009 for studies examining the effect of statins on VT/VF in recipients of ICDs. We retrieved all prospective cohort studies that examined this association. The endpoint was defined as appropriate ICD therapy for VT/VF. The quality of individual studies was assessed using the Newcastle Ottawa Scale.Seven prospective cohort studies met our inclusion criteria with a total of 2278 patients with a mean follow-up of 19.7 months. Pooled analysis of the eligible studies revealed that statin therapy was associated with a 45% reduction in the risk of developing VT/VF in recepients of ICDs [pooled odds ratio (pOR): 0.55; 95% confidence interval: 0.34-0.90; heterogeneity I(2) = 81%, P = 0.02]. In a subgroup analysis, the magnitude of the risk reduction in patients with ischemic cardiomyopathy was 54% (pOR: 0.46, P = 0.05). Sensitivity analysis including studies with higher methodological qualities alone showed a significant protective effect (pOR: 0.48, P = 0.01). There was no evidence of publication bias in the analysis.Our meta-analysis suggests an association between the use of statin and a reduction in the VT/VF occurrence in recipients of ICDs, mainly in patients with ischemic cardiomyopathy. |
15,576 | Antiarrhythmic drug therapy for sustained ventricular arrhythmias complicating acute myocardial infarction. | Few data exist to guide antiarrhythmic drug therapy for sustained ventricular tachycardia/ventricular fibrillation after acute myocardial infarction. The objective of this analysis was to describe the survival of patients with sustained ventricular tachycardia/ventricular fibrillation after myocardial infarction according to antiarrhythmic drug treatment.</AbstractText>We conducted a retrospective analysis of ST-segment elevation myocardial infarction patients with sustained ventricular tachycardia/ventricular fibrillation in Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO) IIB and GUSTO III and compared all-cause death in patients receiving amiodarone, lidocaine, or no antiarrhythmic. We used Cox proportional-hazards modeling and inverse weighted estimators to adjust for baseline characteristics, β-blocker use, and propensity to receive antiarrhythmics. Due to nonproportional hazards for death in early follow-up (0-3 hrs after sustained ventricular tachycardia/ventricular fibrillation) compared with later follow-up (>3 hrs), we analyzed all-cause mortality using time-specific hazards.</AbstractText>Among 19,190 acute myocardial infarction patients, 1,126 (5.9%) developed sustained ventricular tachycardia/ventricular fibrillation and met the inclusion criteria. Patients received lidocaine (n = 664, 59.0%), amiodarone (n = 50, 4.4%), both (n = 110, 9.8%), or no antiarrhythmic (n = 302, 26.8%).</AbstractText>In the first 3 hrs after ventricular tachycardia/ventricular fibrillation, amiodarone (adjusted hazard ratio 0.39, 95% confidence interval 0.21-0.71) and lidocaine (adjusted hazard ratio 0.72, 95% confidence interval 0.53-0.96) were associated with a lower hazard of death-likely evidence of survivor bias. Among patients who survived 3 hrs, amiodarone was associated with increased mortality at 30 days (adjusted hazard ratio 1.71, 95% confidence interval 1.02-2.86) and 6 months (adjusted hazard ratio 1.96, 95% confidence interval 1.21-3.16), but lidocaine was not at 30 days (adjusted hazard ratio 1.19, 95% confidence interval 0.77-1.82) or 6 months (adjusted hazard ratio 1.10, 95% confidence interval 0.73-1.66).</AbstractText>Among patients with acute myocardial infarction complicated by sustained ventricular tachycardia/ventricular fibrillation who survive 3 hrs, amiodarone, but not lidocaine, is associated with an increased risk of death, reinforcing the need for randomized trials in this population.</AbstractText> |
15,577 | Outcomes from prehospital cardiac arrest in blunt trauma patients. | There are few strategies for treating patients who have suffered cardiopulmonary arrest due to blunt trauma (BT-CPA). The aim of this population-based case series observational study was to clarify the outcome of BT-CPA patients treated with a standardized strategy that included an emergency department thoracotomy (EDT) under an emergency medical service (EMS) system with a rapid transportation system.</AbstractText>The 477 BT-CPA registry data were augmented by a review of the detailed medical records in our emergency department (ED) and action reports in the prehospital EMS records.</AbstractText>Of those, 76% were witnessed and 20% were CPA after leaving the scene. In all, 18% of the patients went to the intensive care unit (ICU), the transcatheter arterial embolization (TAE) room, or the operating room (OR). Only 3% survived to be discharged. Among the 363 witnessed patients-11 of whom had ventricular fibrillation (VF) as the initial rhythm, 134 exhibiting pulseless electrical activity (PEA), and 221 with asystole-13, 1, and 3%, respectively, survived to discharge. The most common initial rhythm just after collapse was not VF but PEA, and asystole increased over the 7 min after collapse. There were no differences in the interval between arrival at the hospital and the return of spontaneous circulation between the patients that survived to discharge and deceased patients in the ED, OR, TAE room, or ICU. The longest interval was 17 min.</AbstractText>In BT-CPA patients, a 20-min resuscitation effort and termination of the effort are thought to be relevant. The initial rhythm is not a prognostic indicator. We believe that the decision on whether to undertake aggressive resuscitation efforts should be made on a case-by-case basis.</AbstractText> |
15,578 | Multicenter cohort study of out-of-hospital pediatric cardiac arrest. | To describe a large cohort of children with out-of-hospital cardiac arrest with return of circulation and to identify factors in the early postarrest period associated with survival. These objectives were for planning an interventional trial of therapeutic hypothermia after pediatric cardiac arrest.</AbstractText>A retrospective cohort study was conducted at 15 Pediatric Emergency Care Applied Research Network clinical sites over an 18-month study period. All children from 1 day (24 hrs) to 18 yrs of age with out-of-hospital cardiac arrest and a history of at least 1 min of chest compressions with return of circulation for at least 20 mins were eligible.</AbstractText>One hundred thirty-eight cases met study entry criteria; the overall mortality was 62% (85 of 138 cases). The event characteristics associated with increased survival were as follows: weekend arrests, cardiopulmonary resuscitation not ongoing at hospital arrival, arrest rhythm not asystole, no atropine or NaHCO3, fewer epinephrine doses, shorter duration of cardiopulmonary resuscitation, and drowning or asphyxial arrest event. For the 0- to 12-hr postarrest return-of-circulation period, absence of any vasopressor or inotropic agent (dopamine, epinephrine) use, higher lowest temperature recorded, greater lowest pH, lower lactate, lower maximum glucose, and normal pupillary responses were all associated with survival. A multivariate logistic model of variables available at the time of arrest, which controlled for gender, age, race, and asystole or ventricular fibrillation/ventricular tachycardia anytime during the arrest, found the administration of atropine and epinephrine to be associated with mortality. A second model using additional information available up to 12 hrs after return of circulation found 1) preexisting lung or airway disease; 2) an etiology of arrest drowning or asphyxia; 3) higher pH, and 4) bilateral reactive pupils to be associated with lower mortality. Receiving more than three doses of epinephrine was associated with poor outcome in 96% (44 of 46) of cases.</AbstractText>Multiple factors were identified as associated with survival after out-of-hospital pediatric cardiac arrest with the return of circulation. Additional information available within a few hours after the return of circulation may diminish outcome associations of factors available at earlier times in regression models. These factors should be considered in the design of future interventional trials aimed to improve outcome after pediatric cardiac arrest.</AbstractText> |
15,579 | Treatment of yew leaf intoxication with extracorporeal circulation. | Taxine, a yew tree toxin, is highly cardiotoxic. We report the case of a patient who developed severe cardiac failure and ventricular fibrillation after consuming yew leaves and who made a full recovery after extracorporeal life support. Yew poisoning can be added to the list of potential indications of extracorporeal life support for refractory toxic cardiogenic shock. |
15,580 | A comparison of autopsy detected injuries in a porcine model of cardiac arrest treated with either manual or mechanical chest compressions. | The objective of this study was to evaluate and compare the complications of cardiopulmonary resuscitation after manual or mechanical chest compressions in a swine model of ventricular fibrillation. In this retrospective study, 106 swine were treated with either manual (n=53) or mechanical chest compressions with the LUCAS device (n=53). All swine cadavers underwent necropsy. The animals with no autopsy findings were significantly fewer in the LUCAS group (P=0.004). Sternal fractures were identified in 18 animals in the manual and only two in the LUCAS group (P=0.003). Rib fractures were present in 16 animals in the manual and only four in the LUCAS group (P=0.001). Nine animals in the manual, and two in the LUCAS group had liver hematomas (P=0.026%). In the manual group, eight animals were detected with spleen hematomas whereas no such injury was identified in the LUCAS group (P=0.003). LUCAS devise minimized the resuscitation-related trauma compared with manual chest compressions in a swine model of cardiac arrest. |
15,581 | Acute oral potassium overdose: the role of hemodialysis. | Hyperkalemia is a common condition, particularly in the setting of renal dysfunction. Hyperkalemia due to intentional oral potassium overdose is not commonly reported.</AbstractText>We present a case of acute intentional potassium overdose in a patient with normal renal function resulting in significant hyperkalemia, with a maximum serum potassium concentration of 11 mEq/L. Despite an initial course complicated by various unstable cardiac rhythms, including ventricular tachycardia, ventricular fibrillation, and pulseless electrical activity, the patient was discharged from the hospital neurologically intact. Treatment for hyperkalemia included hemodialysis.</AbstractText>The role of dialysis in potassium overdose is poorly defined.</AbstractText>Based on this case and a review of the medical literature, we recommend hemodialysis for cases of potassium overdose with hemodynamic instability and significantly elevated serum potassium concentrations that do not respond promptly to medical therapy. Hemodialysis should also be considered in cases with underlying renal dysfunction.</AbstractText>© American College of Medical Toxicology 2010</CopyrightInformation> |
15,582 | The effect of statin therapy on ventricular tachyarrhythmias: a meta-analysis. | The objective of this study was to assess whether statin therapy is associated with a reduction in ventricular tachyarrhythmias. Statins have been shown to be beneficial beyond their cholesterol-lowering effects. These pleiotropic effects have been implicated in the protection against atrial fibrillation and the reduction in appropriate implantable cardioverter-defibrillator therapy in patients with coronary artery disease. This meta-analysis was conducted to evaluate whether statins were associated with a reduction in ventricular tachyarrhythmias in patients with coronary artery disease or nonischemic cardiomyopathy. The Medline and Cochrane databases were searched for studies in human subjects published in the English language between 1985 and February 2010. Studies were included in our analysis if they provided data regarding the association between the use of statins and the incidence of ventricular tachycardia/ventricular fibrillation (VT/VF) in patients with coronary artery disease or nonischemic cardiomyopathy. The occurrence of ventricular arrhythmias was defined as the VT/VF occurrence or appropriate implantable cardioverter-defibrillator therapy for VT/VF. Of the 166 identified articles, nine prospective studies with 150,953 patients enrolled met our inclusion criteria and were included in this analysis. Using a random effects model, statin therapy was associated with a 31% reduction in the risk of VT/VF when compared with the group not on statin therapy (pooled relative risk = 0.69, 95% confidence interval, 0.58-0.83; heterogeneity I² = 57.3%). There was a low likelihood of publication bias in this analysis (Egger's test P = 0.957). Statin use in patients with coronary artery disease or nonischemic cardiomyopathy is associated with a 31% reduction in the development of ventricular tachyarrhythmias. |
15,583 | Postischemic cardiac recovery in heme oxygenase-1 transgenic ischemic/reperfused mouse myocardium. | Heme oxygenase-1 (HO-1) transgenic mice (Tg) were created using a rat HO-1 genomic transgene. Transgene expression was detected by RT-PCR and Western blots in the left ventricle (LV), right ventricle (RV) and septum (S) in mouse hearts, and its function was demonstrated by the elevated HO enzyme activity. Tg and non-transgenic (NTg) mouse hearts were isolated and subjected to ischemia/reperfusion. Significant post-ischemic recovery in coronary flow (CF), aortic flow (AF), aortic pressure (AOP) and first derivative of AOP (AOPdp/dt) were detected in the HO-1 Tg group compared to the NTg values. In HO-1 Tg hearts treated with 50 μmol/kg of tin protoporphyrin IX (SnPPIX), an HO enzyme inhibitor, abolished the post-ischemic cardiac recovery. HO-1 related carbon monoxide (CO) production was detected in NTg, HO-1 Tg and HO-1 Tg + SnPPIX treated groups, and a substantial increase in CO production was observed in the HO-1 Tg hearts subjected to ischemia/reperfusion. Moreover, in ischemia/reperfusion-induced tissue Na(+) and Ca(2+) gains were reduced in HO-1 Tg group in comparison with the NTg and HO-1 Tg + SnPPIX treated groups; furthermore K(+) loss was reduced in the HO-1 Tg group. The infarct size was markedly reduced from its NTg control value of 37 ± 4% to 20 ± 6% (P < 0.05) in the HO-1 Tg group, and was increased to 47 ± 5% (P < 0.05) in the HO-1 knockout (KO) hearts. Parallel to the infarct size reduction, the incidence of total and sustained ventricular fibrillation were also reduced from their NTg control values of 92% and 83% to 25% (P < 0.05) and 8% (P < 0.05) in the HO-1 Tg group, and were increased to 100% and 100% in HO-1 KO(-/-) hearts. Immunohistochemical staining of HO-1 was intensified in HO-1 Tg compared to the NTg myocardium. Thus, the HO-1 Tg mouse model suggests a valuable therapeutic approach in the treatment of ischemic myocardium. |
15,584 | Predictive factors for positive coronary angiography in out-of-hospital cardiac arrest patients. | Coronary angiography is often performed in survivors of out-of-hospital cardiac arrest, but little is known about the factors predictive of a positive coronary angiography. Our aim was to determine these factors.</AbstractText>In this 7-year retrospective study (January 2000-December 2006) conducted by a French out-of-hospital emergency medical unit, data were collected according to Utstein style guidelines on all out-of-hospital cardiac arrest patients with suspected coronary disease who recovered spontaneous cardiac activity and underwent early coronary angiography. Coronary angiography was considered positive if a lesion resulting in more than a 50% reduction in luminal diameter was observed or if there was a thrombus at an occlusion site.</AbstractText>Among the 4621 patients from whom data were collected, 445 were successfully resuscitated and admitted to hospital. Of these, 133 were taken directly to the coronary angiography unit, 95 (71%) had at least one significant lesion, 71 (53%) underwent a percutaneous coronary intervention, and 30 survived [23%, 95% confidence interval (CI): 16-30]. According to multivariate analysis, the factors predictive of a positive coronary angiography were a history of diabetes [odds ratio (OR): 7.1, 95% CI: 1.4-36], ST segment depression on the out-of-hospital ECG (OR: 5.4, 95% CI: 1.1-27.8), a history of coronary disease (OR: 5.3, 95% CI: 1.4-20.1), cardiac arrest in a public place (OR: 3.7, 95% CI: 1.3-10.7), and ventricular fibrillation or ventricular tachycardia as initial rhythm (OR: 3.1, 95% CI: 1.1-8.6).</AbstractText>Among the factors identified, diabetes and a history of coronary artery were strong predictors for a positive coronary angiography, whereas ST segment elevation was not as predictive as expected.</AbstractText> |
15,585 | Atrial remodeling in an ovine model of anthracycline-induced nonischemic cardiomyopathy: remodeling of the same sort. | All preclinical studies of atrial remodeling in heart failure (HF) have been confined to a single model of rapid ventricular pacing. To evaluate whether the atrial changes were specific to the model or represented an end result of HF, this study aimed to characterize atrial remodeling in an ovine model of doxorubicin-induced cardiomyopathy.</AbstractText>Fourteen sheep, 7 with cardiomyopathy induced by repeated intracoronary doxorubicin infusions and 7 controls, were studied. The development of HF was monitored by cardiac imaging and hemodynamic parameters. Open chest electrophysiological study was performed using custom-made 128-electrode epicardial plaque assessing effective refractory period (ERP) and conduction velocity. Atrial tissues were harvested for structural analysis. The HF group had demonstrable moderate global HF (left ventricular ejection fraction [LVEF]: 37.1 vs 46.4%; P = 0.003) and showed the following compared to controls: left atrial dilatation (P = 0.02) and dysfunction (P = 0.005); longer P-wave duration (P < 0.05); higher ERP at all cycle lengths (P ≤ 0.002) and locations (P < 0.001); slower conduction velocity (P < 0.001); increased conduction heterogeneity index (P < 0.001); increased atrial fibrosis (right atrial [RA]: 5.9 ± 2.6 vs 2.8 ± 0.9%; P < 0.0001, left atrial [LA]: 3.7 ± 2.2 vs 2.4 ± 1.1%; P = 0.002), and longer induced atrial fibrillation (AF) episodes (16 ± 22 vs 2 ± 3 seconds; P = 0.04).</AbstractText>In this model of HF, there was significant atrial remodeling characterized by atrial enlargement/dysfunction, increased fibrosis, slowed/heterogeneous conduction, and increased refractoriness associated with more sustained AF. These findings appear the "same sort" to previous models of HF implicating a final common substrate leading to the development of AF in HF.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
15,586 | Sympathetic-parasympathetic interaction in health and disease: abnormalities and relevance in heart failure. | Sympathetic-parasympathetic interaction plays a major role in the evolution and outcome of many cardiovascular disorders. Nonetheless, a thorough understanding of this relationship and of its potential implications for prognosis and management still escapes many cardiologists. This article reviews the background of sympathetic-parasympathetic interactions focusing on the best direct evidence available, namely direct neural recordings of the activity of single vagal and sympathetic fibers directed to the heart. It examines indirect but highly reliable markers of this interaction as they can be studied in the clinical setting of ischemic heart disease and of heart failure, focusing primarily on the experimental and clinical studies of baroreflex sensitivity. It concludes by drawing inferences likely to lead to a novel approach to the management of heart failure, resulting from the knowledge gained about the vagal control of the heart and based on electrical vagal stimulation. |
15,587 | Physician experience in addition to ACLS training does not significantly affect the outcome of prehospital cardiac arrest. | Little data exists on whether the physicians' skills in responding to cardiac arrest are fully developed after the advanced cardiac life support (ACLS) course, or if there is a significant improvement in their performance after an initial learning curve.</AbstractText>To estimate the effect of physician experience on the results of prehospital cardiac arrests.</AbstractText>Prospective data were collected on all prehospital resuscitative attempts in the area by ACLS-trained ambulance physicians.</AbstractText>Of 232 attempted cardiac resuscitations, 96 (41%) patients survived to hospital admission and 44 (19%) were discharged alive. A group of 39 physicians responded to from one up to 29 cases with a mean of four cases. Physicians responding to five or fewer cases had a trend to fewer patients surviving to admission compared with those responding to six or more (36 vs. 45%, P=0.31) but no difference was found on survival to discharge (19 vs. 20%, P=0.87).</AbstractText>In this study, resuscitative experience of the physician did not have a significant effect on survival suggesting that experience does not significantly add to the current ACLS training in responding to ventricular fibrillation/ventricular tachycardia. More studies are needed.</AbstractText> |
15,588 | Intracardiac echocardiography off piste? Closure of the left atrial appendage using ICE and local anesthesia. | Left atrial appendage (LAA) occlusion is increasingly accepted to reduce the risk of stroke in patients with atrial arrhythmia who are unsuitable for routine anticoagulation. It is generally performed under general anesthesia, guided by transoesophageal echocardiography with accurate imaging being essential for correct deployment of the device. We present a case where LAA occlusion was done under local anesthesia in a high-anesthetic risk patient, using novel placement of an intracardiac echo probe via a Mullins sheath in the right ventricular outflow tract and pulmonary artery. This allowed accurate visualization of device deployment in the LAA. This technique may increase the spectrum of patients who may benefit from the procedure and decrease procedure time, fluoroscopy, and procedure-related morbidity. |
15,589 | The persistent problem of new-onset postoperative atrial fibrillation: a single-institution experience over two decades. | Postoperative atrial fibrillation is the most common complication after cardiac surgery. A variety of postoperative atrial fibrillation risk factors have been reported, but study results have been inconsistent or contradictory, particularly in patients with preexisting atrial fibrillation. The incidence of postoperative atrial fibrillation was evaluated in a group of 10,390 patients undergoing cardiac surgery among a comprehensive range of risk factors to identify reliable predictors of postoperative atrial fibrillation.</AbstractText>This 20-year retrospective study examined the relationship between postoperative atrial fibrillation and demographic factors, preoperative health conditions and medications, operative procedures, and postoperative complications. Multivariate logistic regression models were used to evaluate potential predictors of postoperative atrial fibrillation.</AbstractText>Increasing age, mitral valve surgery (odds ratio=1.91), left ventricular aneurysm repair (odds ratio=1.57), aortic valve surgery (odds ratio=1.52), race (Caucasian) (odds ratio=1.51), use of cardioplegia (odds ratio=1.36), use of an intraaortic balloon pump (odds ratio=1.28), previous congestive heart failure (odds ratio=1.28), and hypertension (odds ratio=1.15) were significantly associated with postoperative atrial fibrillation. The non-linear relationship between age and postoperative atrial fibrillation revealed the acceleration of postoperative atrial fibrillation risk in patients aged 55 years or more. In patients undergoing coronary artery bypass grafting, increasing age and previous congestive heart failure were the only factors associated with a higher risk of postoperative atrial fibrillation. There was no trend in incidence of postoperative atrial fibrillation over time. No protective factors against postoperative atrial fibrillation were detected, including commonly prescribed categories of medications.</AbstractText>The persistence of the problem of postoperative atrial fibrillation and the modest predictability using common risk factors suggest that limited progress has been made in understanding its cause and treatment.</AbstractText>Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
15,590 | Successful catheter ablation of focal ventricular fibrillation in a patient with nonischemic dilated cardiomyopathy. | A 64-year-old man with nonischemic dilated cardiomyopathy and a biventricular defibrillator presented with recurrent ventricular fibrillation (VF) and defibrillator shocks. Evaluation of the intracardiac electrograms from his defibrillator demonstrated the consistent initiation of VF by unifocal premature ventricular complexes (PVCs). Noncontact mapping demonstrated the origin of the PVC to be near the left ventricular outflow tract toward the mitral valve ring. Several applications of radiofrequency at this position led to complete cessation of PVCs and prevented further VF. He has not had any further ventricular arrhythmias or defibrillator discharges during follow-up. |
15,591 | Proarrhythmic ECG deterioration caused by myocardial ischemia of the conus branch artery in patients with a Brugada ECG pattern. | The Brugada-type electrocardiogram (ECG) is characterized by ST-segment elevation in the right precordial ECG leads and has been reported to have the potential of sudden death. Right ventricular outflow tract supplied from the conus branch of the coronary artery (CB) is considered as the anatomopathologic substrate of Brugada syndrome. We experienced two asymptomatic patients with a saddleback Brugada-type ECG who exhibited a dynamic ECG conversion to a coved type following a ventricular fibrillation/ventricular tachycardia (VT/VF) episode when myocardial ischemia occurred exclusively at the CB. Some types of Brugada syndrome might be caused VT/VF by selective myocardial ischemia at the CB. |
15,592 | Ventricular fibrillation and ventricular tachycardia triggered by late-coupled ventricular extrasystoles in a Brugada syndrome patient. | Premature ventricular complexes (PVC) falling after the end of the T wave triggered ventricular fibrillation (VF) at night and monomorphic ventricular tachycardia (MVT) during daytime, in a recipient of implantable cardioverter defibrillator with Brugada syndrome. Treatment with bepridil (1) decreased the height of ST segment elevation in leads V1-V3, (2) completely eliminated VF, and (3) markedly decreased the incidence of PVC and MVT. Albeit rare, VF can be triggered by late-coupled PVC, due to a mechanism other than phase 2 reentry in some patients with Brugada syndrome. |
15,593 | External and internal biphasic direct current shock doses for pediatric ventricular fibrillation and pulseless ventricular tachycardia. | To determine energy dose and number of biphasic direct current shocks for pediatric ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT).</AbstractText>Observation of preshock and postshock rhythms, energy doses, and number of shocks.</AbstractText>Pediatric hospital.</AbstractText>Shockable ventricular dysrhythmias.</AbstractText>None.</AbstractText>Forty-eight patients with VF or pulseless VT received external shock at 1.7 ± 0.8 (mean ± SD) J/kg. Return of spontaneous circulation (ROSC) occurred in 23 (48%) patients with 2.0 ± 1.0 J/kg, but 25 (52%) patients remained in VF after 1.5 ± 0.7 J/kg (p = .05). In 24 non-responding patients, additional 1-8 shocks (final dose, 2.8 ± 1.2 J/kg) achieved ROSC in 14 (58%) with 2.6 ± 1.1 J/kg but not in 10 (42%) with 3.2 ± 1.2 J/kg (not significant). Overall, 37 (77%) patients achieved ROSC with 2.2 ± 1.1 J/kg (range, 0.5-5.0 J/kg). Eight patients without ROSC recovered with cardiopulmonary bypass and internal direct current shock. At 13 subsequent episodes of VF or VT among eight patients, five achieved ROSC and survived. In combined first and subsequent resuscitative episodes, doses in the range of 2.5 to < 3 J/kg achieved most cases of ROSC. Survival for > 1 yr was seen in 28 (78%) of 36 patients with VF and seven (58%) of 11 patients with VT, with 35 (73%) overall. Lack of ROSC was associated with multiple shocks (p = .003). Repeated shocks with adhesive pads had significantly less impedance (p < .001). Pads in an anteroposterior position achieved highest ROSC rate. Internal shock for another 48 patients with VF or VT achieved ROSC in 28 (58%) patients with 0.7 ± 0.4 J/kg but not in 20 patients with 0.4 ± 0.3 J/kg (p = .01). Nineteen of the nonresponders who received additional internal 1-9 shocks at 0.6 ± 0.5 J/kg and one patient given extracorporeal membrane oxygenation all recovered, yielding 100% ROSC, but 1-yr survival tallied 43 (90%) patients.</AbstractText>The initial biphasic direct current external shock dose of 2 J/kg for VF or pulseless VT is inadequate. Appropriate doses for initial and subsequent shocks seem to be in the range of 3-5 J/kg. Multiple shocks do not favor ROSC. The dose for internal shock is 0.6-0.7 J/kg.</AbstractText> |
15,594 | Contemporary indications and therapeutic implications for digoxin use. | Heart failure (HF) is a leading cause of morbidity and mortality. Appropriate medical therapy using angiotensin converting enzyme inhibitors and beta-blockers improves outcomes in HF, whereas the role of digoxin is still not clearly defined. Digoxin is currently recommended for patients with HF who are symptomatic despite standard therapy and for controlling the ventricular rate in atrial fibrillation. Digoxin is a time-tested drug that accounts for 20 million drug prescriptions annually in the United States. It has favorable hemodynamic effects for patients with HF and atrial tachyarrhythmias. We conducted a systematic literature search for the current indications for digoxin. Despite extensive research and safety data, the literature suggests that digoxin is underused in clinical settings. Citing the literature where available, our review highlights the various clinical settings where digoxin is indicated. Despite difficulties with designing prospective studies in acute HF settings and lack of outcomes data, we believe that digoxin will continue to serve an important role in optimizing care in certain acute and chronic cardiac conditions. |
15,595 | The AED in resuscitation: it's not just about the shock. | The automated external defibrillator (AED), in combination with effective cardiopulmonary resuscitation (CPR), is a critical part of the American Heart Association's "Chain of survival." Newer guidelines have simplified resuscitation and emphasized the importance of CPR in providing rapid and deep compressions with minimal interruptions; in fact, CPR should resume immediately after the shock given by the AED, without the delay entailed in checking for pulse or rhythm conversion. Our experience with the AED aboard aircraft, showing 40% long-term survival with the AED in ventricular fibrillation, demonstrated the safety and efficacy of the device. Despite this and other reports of successful AED deployment, AEDs are not yet available at all public locations. Prospective research, as undertaken by the Resuscitation Outcomes Consortium, will be the key to future refinements of the guidelines and enhanced survival with use of the AED in sudden cardiac arrest. |
15,596 | Therapeutic Hypothermia: What's Hot about Cold. | Reducing body temperature to 33 °C in patients who have been resuscitated from cardiac arrest but who remain comatose can ameliorate anoxic encephalopathy and improve recovery. Experimental animal studies have suggested that cooling to 33 °C also aids the resuscitative process itself, facilitating the resumption of spontaneous circulation (ROSC). The mechanism of cooling benefit is probably the reduction of metabolic demand of most organs, and reduced production of toxic metabolites and reactive oxygen species. External cooling by application of ice or pads through which cold water circulates is effective but requires up to 8 hours to achieve the target temperature of 33 °C. Our goal was to develop a faster method of cooling that could be initiated during cardiopulmonary resuscitation. In anesthetized swine, we induced ventricular fibrillation by passing alternating current down an electrode catheter in the right ventricle. We then ventilated the animals' lungs with liquid perfluorocarbons (PFCs), a technique known as total liquid ventilation (TLV). Perfluorocarbons are oxygen-carrying modules; we pre-oxygenated the PFCs by bubbling 100% O(2) through the solution for 2 minutes before use, and pre-cooled the PFCs to -15 °C. The cold oxygenated PFCs reduced pulmonary artery temperature (a surrogate for myocardial temperature) to 33 °C in about 6 minutes. Using this technique we achieved ROSC in 8 of 11 (82%) animals given TLV versus 3 of 11 (27%) control animals receiving conventional CPR without PFCs (P<0.05). We also compared the cold TLV technique with the administration of intravenous iced saline to achieve hypothermia. Both the cold TLV and cold saline techniques produced rapid hypothermia, but we could achieve ROSC in only 2 of 8 (25%) animals given cold saline versus 7 of 8 (88%) given cold TLV. This result is likely due to the rise in right atrial pressure and corresponding reduction in coronary perfusion pressure caused by volume loading with IV saline, in addition to the higher pO(2) associated with pre-oxygenated PFCs. Cold TLV is a promising technique for achieving rapid intra-arrest and post-resuscitation hypothermia in patients experiencing cardiac arrest. |
15,597 | Cardiac Resynchronization Therapy in continuous flow Left Ventricular Assist Device Recipients: A Systematic Review and Meta-analysis from ELECTRAM Investigators. | Whether cardiac resynchronization therapy (CRT) continues to augment left ventricular remodeling in patients with the continuous-flow left ventricular assist device (cf-LVAD) remains unclear.</AbstractText>We performed a systematic review and meta-analysis of all clinical studies examining the role of continued CRT in end-stage heart failure patients with cf-LVAD reporting all-cause mortality, ventricular arrhythmias, and ICD shocks. Mantel-Haenszel risk ratio (RR) random-effects model was used to summarize data.</AbstractText>Eight studies (7 retrospective and 1 randomized) with a total of 1,208 unique patients met inclusion criteria. There was no difference in all-cause mortality (RR 1.08, 95% CI 0.86 - 1.35, p = 0.51, I2=0%), all-cause hospitalization (RR 1.01, 95% CI 0.76-1.34, p = 0.95, I2</sup>=11%), ventricular arrhythmias (RR 1.08, 95% CI 0.83 - 1.39, p = 0.58, I2</sup> =50%) and ICD shocks (RR 0.87, 95% CI 0.57 - 1.33, p = 0.52, I2</sup> =65%) comparing CRT versus non-CRT. Subgroup analysis demonstrated significant reduction in ventricular arrhythmias (RR 0.76, 95% CI 0.64 - 0.90, p = 0.001) and ICD shocks (RR 0.65, 95% CI 0.44 - 0.97, p = 0.04) in "CRT on" group versus "CRT off" group.</AbstractText>CRT was not associated with a reduction in all-cause mortality or increased risk of ventricular arrhythmias and ICD shocks compared to non-CRT in cf-LVAD patients. It remains to be determined which subgroup of cf-LVAD patients benefit from CRT. The findings of our study are intriguing, and therefore, larger studies in a randomized prospective manner should be undertaken to address this specifically.</AbstractText> |
15,598 | The Role of Magnesium in the Management of Atrial Fibrillation with Rapid Ventricular Rate. | Atrial fibrillation is currently managed with a variety of rate controlling and antiarrhythmic agents. Often, magnesium is used as adjunctive therapy, however, the benefit it provides in managing Afib with RVR has been debated. This study aimed to determine if IV MgSO4 administration in conjunction with standard therapy provides any synergistic effect in acute and prolonged control of Afib with RVR.</AbstractText>This was a retrospective study involving ninety patients with episodes of Afib with RVR during their hospitalization. The treatment group included those that had received magnesium (n=32) along with standard management and the control group (n=58) received only standard management. Heart rates at different time intervals were collected. Dose dependent effects of IV MgSO4 on heart rates were also evaluated.</AbstractText>Patients that received magnesium had a lower mean heart rate (85 BPM versus 96 BPM, P<0.05) 24 hours after onset of the episode. Also, in the last 16 hours of observation, it appeared that administration of higher levels of magnesium resulted in statistically lower heart rates. In the group of patients that received 2 grams of magnesium, the mean heart rate at 8 hours was 103.4 beats/min and 84.8 beats/min at 24 hours (p<0.01). This same trend was not seen in patients that received 1 gram of magnesium or in the control group.</AbstractText>Overall, the use of IV MgSO4 as an adjunctive treatment permitted normalization of the heart rate progressively that continued to at least 24 hours.</AbstractText> |
15,599 | Clinical and Echocardiographic Predictors of Atrial Fibrillation after Coronary Artery Bypass Grafting. | To detect the clinical and echocardiographic parameters that predict AF in coronary artery disease (CAD) patients after coronary artery bypass surgery (CABG).</AbstractText>One hundred CAD patients scheduled for CABG were included. Standard 2D, PW Doppler and 2D speckle tracking echocardiography were performed to assess left atrial (LA) and ventricular (LV) function and their role in predicting post-operative atrial fibrillation (POAF).</AbstractText>Twenty-two percent of patients developed POAF. POAF patients were significantly older (P= 0.001) with increased heart rate (P= 0.001). POAF patients had increased LA diameters and volumes (P < 0.001). Left ventricular ejection fraction (LVEF) was significantly lower in POAF patients (P < 0.004). POAF patients had significantly lower LA and LV global longitudinal strain (LVGLS) (p < 0.001). Clinical predictors of POAF were age and heart rate (P < 0.001). While, echocardiographic measures associated with POAF were LA and LV global longitudinal strain (P <0.001). LA longitudinal strain ≤ 23.1 (85% sensitivity and 66% specificity ) and LVGLS ≤ -14.4 (70% sensitivity and 85% specificity) predicted POAF.</AbstractText>Preoperative LA and LV global longitudinal strain predicts POAF in CABG patients. Echocardiographic deformation measures can enhance clinical profile to identify patients at high risk for POAF.</AbstractText> |
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