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12,200 | Growth differentiation factor-15 is a useful prognostic marker in patients with heart failure with preserved ejection fraction. | Circulating growth differentiation factor 15 (GDF-15) levels correlate with heart mass and fibrosis; however, little is known about its value in predicting the prognosis of patients with heart failure with preserved ejection fraction (HFpEF).</AbstractText>We measured serum GDF-15 levels in 149 consecutive patients with left ventricular diastolic dysfunction (LVDD) and normal LV ejection fraction (>50%) and followed them for cardiovascular events. LVDD was defined according to the European Society of Cardiology guidelines.</AbstractText>The New York Heart Association functional class and circulating B-type natriuretic peptide (BNP) levels were significantly higher in the high-GDF-15 group (n = 75; greater than or equal to the median value [3694 pg/mL]) than in the low-GDF-15 group (n = 74). Patients were divided into HFpEF and LVDD groups according to the presence or absence of HF. Serum GDF-15 levels were significantly higher in the HFpEF group (n = 73) than in the LVDD group (n = 76) (median, 4215 [interquartile range, 3382-5287] vs 3091 [interquartile range, 2487-4217 pg/mL]; P < 0.0001). Kaplan-Meier curve analysis showed a significantly higher probability of cardiovascular events in the high-GDF-15 group than in the low-GDF-15 group for data of all patients (log-rank test P = 0.006) and data of patients in the HFpEF group only (P = 0.014). Multivariate Cox hazard analysis identified age (hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.87-0.98; P = 0.008), atrial fibrillation (HR, 7.95; 95% CI, 1.98-31.85, P = 0.003), lnBNP (HR, 3.37; 95% CI, 1.73-6.55; P < 0.0001), and GDF-15 (ln[GDF-15]) (HR, 4.74; 95% CI, 1.26-17.88, P = 0.022) as independent predictors of primary end points.</AbstractText>GDF-15 is a potentially useful prognostic biomarker in patients with HFpEF.</AbstractText>Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,201 | Electrophysiological and haemodynamic effects of vernakalant and flecainide in dyssynchronous canine hearts. | About one-third of patients with mild dyssynchronous heart failure suffer from atrial fibrillation (AF). Drugs that convert AF to sinus rhythm may further slowdown ventricular conduction. We aimed to investigate the electrophysiological and haemodynamic effects of vernakalant and flecainide in a canine model of chronic left bundle branch block (LBBB).</AbstractText>Left bundle branch block was induced in 12 canines. Four months later, vernakalant or flecainide was administered using a regime, designed to achieve clinically used plasma concentrations of the drugs, n = 6 for each drug. Epicardial electrical contact mapping showed that both drugs uniformly prolonged myocardial conduction time. Vernakalant increased QRS width significantly less than flecainide (17 ± 13 vs. 34 ± 15%, respectively). Nevertheless, both drugs equally decreased LVdP/dtmax by ∼15%, LVdP/dtmin by ∼10%, and left ventricular systolic blood pressure by ∼5% (P = n.s. between drugs).</AbstractText>Vernakalant prolongs ventricular conduction less than flecainide, but both drugs had a similar, moderate negative effect on ventricular contractility and relaxation. Part of these reductions seems to be related to the increase in dyssynchrony.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
12,202 | Implantable cardioverter-defibrillators for treatment of sustained ventricular arrhythmias in patients with Chagas' heart disease: comparison with a control group treated with amiodarone alone. | Evidence is inconclusive concerning the benefit of implantable cardioverter-defibrillators (ICDs) for secondary prevention of mortality in patients with Chagas' heart disease (ChHD). The aim of this study was to compare the outcomes of ChHD patients with life-threatening ventricular arrhythmias (VAs), who were treated either with ICD implantation plus amiodarone or with amiodarone alone.</AbstractText>The ICD group [76 patients; 48 men; age, 57 ± 11 years; left ventricular ejection fraction (LVEF), 39 ± 12%] and the historical control group treated with amiodarone alone (28 patients; 18 men; age, 54 ± 10 years; LVEF, 41 ± 10%) had comparable baseline characteristics, except for a higher use of beta-blockers in the ICD group (P < 0.0001). Amiodarone was also used in 90% of the ICD group. Therapy with ICD plus amiodarone resulted in a 72% reduced risk of all-cause mortality (P = 0.007) and a 95% reduced risk of sudden death (P = 0.006) compared with amiodarone-only therapy. The survival benefit of ICD was greatest in patients with LVEF < 40% (P = 0.01) and was not significant in those with LVEF ≥ 40% (P = 0.15). Appropriate ICD therapies occurred in 72% of patients and the rates of interventions were similar across patients with LVEF < 40% and ≥40%.</AbstractText>Compared with amiodarone-only therapy, ICD implantation plus amiodarone reduced the risk of all-cause mortality and sudden death in ChHD patients with life-threatening VAs. Patients with LVEF < 40% derived significantly more survival benefit from ICD therapy. The majority of ICD-treated patients received appropriate therapies regardless of the LV systolic function.</AbstractText> |
12,203 | A diagnostic dilemma: early repolarization syndrome associated with ventricular fibrillation. | An early repolarization (ER) pattern, characterized by J-point elevation, slurring of the terminal part of the QRS and ST-segment elevation, is a common finding on the 12-lead electrocardiogram. It has been suggested that J-point elevation, which was considered benign for many years, may play a critical role in the pathogenesis of idiopathic ventricular fibrillation (VF). Recent studies have shown that an ER pattern in inferior leads or inferolateral leads is associated with increased risk for life-threatening arrhythmias. We report the case of a 52-year-old man with no structural heart disease whose electrocardiogram showed type 2 ER pattern (with evidence of J-point and ST-segment elevation in electrocardiogram leads II, III, and aVF). The patient presented with VF. |
12,204 | The degree of left atrial structural remodeling impacts left ventricular ejection fraction in patients with atrial fibrillation. | The extent of left atrial (LA) wall structural remodeling (fibrosis) detected by late gadolinium enhancement-magnetic resonance imaging (LGE-MRI) is correlated with advanced atrial fibrillation (AF). The concomitant occurrence of AF and left ventricular (LV) dysfunction is not uncommon. We studied the effect of LA fibrosis, a confounder of both AF and LV dysfunction, on LV ejection fraction (EF).</AbstractText>For the analysis, we identified and included 384 patients from our retrospective AF database who underwent LGE-MRI and transthoracic echocardiography prior to AF ablation. Based on the degree of LA fibrosis, patients were categorized into four stages as: Utah 1 (<5% LA fibrosis), Utah 2 (5-20% fibrosis), Utah 3 (20-35% fibrosis), and Utah 4 (>35% fibrosis).</AbstractText>The average pre-ablation LVEF was 60.5%±8.5% (n=24) in Utah stage 1 patients, 55.7%±10.3% (n=240) in Utah stage 2 patients, 51.7±11.5% (n=90) in Utah stage 3 patients, and 48.9%±11.6% (n=30) in Utah stage 4 patients (p<0.001, one-way ANOVA). The percentage of LA fibrosis was significantly negatively correlated to LVEF pre-ablation in a univariate analysis (p<0.001). In a multivariate model accounting for age, gender, AF type, and comorbidities such as diabetes and hypertension, Utah stage remained a significant predictor of pre-ablation EF (p<0.001).</AbstractText>Patients with extensive LA fibrosis appear to have depressed LV function pre-ablation, suggesting that structural remodeling in the LA may also be triggering and promoting remodeling within the ventricular myocardium.</AbstractText> |
12,205 | Pharmacokinetics of pilsicainide hydrochloride for injection in healthy Chinese volunteers: a randomized, parallel-group, open-label, single-dose study. | Pilsicainide hydrochloride is a class IC antiarrhythmic agent used for the treatment of supraventricular and ventricular arrhythmias and atrial fibrillation.</AbstractText>The objective of the present study was to determine the pharmacokinetics (PK) of a pilsicainide hydrochloride injection in healthy Chinese adults. The study was conducted to meet China State Food and Drug Administration requirements for the marketing of the new generic formulation of pilsicainide hydrochloride.</AbstractText>This Phase I, randomized, parallel-group, open-label, single-dose PK study was conducted in healthy Chinese volunteers. Subjects were randomized to receive a single dose of 0.25-, 0.50-, and 0.75-mg/kg pilsicainide hydrochloride with a 10-minute intravenous infusion. Serial blood and urine samples were collected up to 24 hours after dosing; drug concentrations in plasma and urine were then determined by using LC-MS/MS. The PK parameters of pilsicainide were calculated from the plasma concentration-time data according to noncompartmental methods. Safety profile was evaluated by monitoring adverse events, clinical laboratory parameters, and the results of 12-lead ECGs.</AbstractText>Thirty healthy volunteers (mean [SD] age, 28.0 [4.95] years; weight, 59.3 [6.51] kg; height, 165.0 [7.25] cm; body mass index, 21.7 [1.94] kg/m(2)) were randomly divided into 3 groups, each consisting of 5 men and 5 women. After single-dose intravenous administration of 0.25, 0.50, and 0.75 mg/kg of pilsicainide hydrochloride, mean Cmax was 0.34 (0.11), 0.54 (0.15), and 1.05 (0.19) μg/mL, respectively; AUC0-24 was 0.76 (0.12), 1.61 (0.37), and 2.61 (0.46) h · μg/mL; and AUC0-∞ was 0.79 (0.13), 1.71 (0.46), and 2.72 (0.50) h · μg/mL. The ranges for t½z, CL, and Vz were 5.19 to 5.98 hours, 4.73 to 5.44 mL/min/kg, and 2.23 to 0.58 L/kg, respectively. The mean urinary recovery rate within 24 hours was 75.0% (12.0%), 65.0% (19.2%), and 66.4% (14.1%). Men and women had significantly different AUC0-24 values in the 0.50-mg/kg dose group (P = 0.044), and Vz showed significant differences between men and women in all 3 dose groups (P = 0.001). According to ECG parameters, PR intervals were significantly prolonged after administration at all 3 doses (P = 0.034, P < 0.001, and P = 0.034); no significant changes were seen in QRS width, QTc interval, or other parameters.</AbstractText>Pilsicainide hydrochloride demonstrated linear PK, and the increase in the exposure of pilsicainide (AUC0-24 and AUC0-∞) was dose proportional after single doses of 0.25, 0.50, and 0.75 mg/kg. All 3 pilsicainide hydrochloride doses were well tolerated in these Chinese volunteers. ChiCTR-ONC-13003546.</AbstractText>Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.</CopyrightInformation> |
12,206 | Application of machine learning techniques to analyse the effects of physical exercise in ventricular fibrillation. | This work presents the application of machine learning techniques to analyse the influence of physical exercise in the physiological properties of the heart, during ventricular fibrillation. To this end, different kinds of classifiers (linear and neural models) are used to classify between trained and sedentary rabbit hearts. The use of those classifiers in combination with a wrapper feature selection algorithm allows to extract knowledge about the most relevant features in the problem. The obtained results show that neural models outperform linear classifiers (better performance indices and a better dimensionality reduction). The most relevant features to describe the benefits of physical exercise are those related to myocardial heterogeneity, mean activation rate and activation complexity. |
12,207 | Vasospastic angina and Ca channel blockers. | Coronary artery spasm is one of the causes of angina pectoris,acute myocardial infarction and ventricular fibrillation-related sudden death. It has been established that Ca channel blockers are protective against vasospastic angina (VSA) and treatment with Ca channel blockers provides a better prognosis of VSA. However, it is not still clarified what kinds of Ca channel blockers shows the best prognosis of VSA. We performed a meta-analysis in which 4Ca channel blockers amlodipine, nifedipine, benidipine and diltiazem were used for the treatment of VSA patients and found that among 4 Ca channel blockers, benidipine showed a statistically significant better prognostic effect on MACE than amlodipine, nifedipine or diltiazem. |
12,208 | Cardiac arrythmias: multimodal assessment integrating body surface ECG mapping into cardiac imaging. | To demonstrate the feasibility of comprehensive assessment of cardiac arrhythmias by combining body surface electrocardiographic (ECG) mapping (BSM) and imaging.</AbstractText>This study was approved by the institutional review board, and all patients gave written informed consent. Twenty-seven patients referred for electrophysiologic procedures in the context of ventricular tachycardia (VT) (n = 9), Wolff-Parkinson-White (WPW) syndrome (n = 2), atrial fibrillation (AF) (n = 13), or scar-related ventricular fibrillation (VF) (n = 3) were examined. Patients underwent BSM and imaging with multidetector computed tomography (CT) (n = 12) and/or delayed enhanced magnetic resonance (MR) imaging (n = 23). BSM was performed by using a 252-electrode vest that enabled the computation of epicardial electrograms from body surface potentials. The epicardial geometry used for BSM was registered to the epicardial geometry segmented from imaging data by using an automatic algorithm. The output was a three-dimensional cardiac model that integrated cardiac anatomy, myocardial substrate, and epicardial activation.</AbstractText>Acquisition, segmentation, and registration were feasible in all patients. In VT, this enabled a noninvasive assessment of the arrhythmia mechanism and its location with respect to the myocardial substrate, coronary vessels, and phrenic nerve. In WPW syndrome, this enabled understanding of complex accessory pathways resistant to previous ablation. In AF and VF, this enabled the noninvasive assessment of arrhythmia mechanisms and the analysis of rotor trajectories with respect to the myocardial substrate. In all patients, models were successfully integrated in navigation systems and used to guide mapping and ablation.</AbstractText>By combining information on anatomy, substrate, and electrical activation, the fusion of BSM and imaging enables comprehensive noninvasive assessment of cardiac arrhythmias, with potential applications for diagnosis, prognosis, and ablation targeting. Online supplemental material is available for this article.</AbstractText>RSNA, 2013</CopyrightInformation> |
12,209 | [Masquerading bundle branch block]. | We here describe a surface 12-lead electrocardiogram (ECG) of a 72-year-old female with a prior history of breast cancer and chemotherapy-induced cardiomyopathy. An echocardiogram revealed left ventricular dysfunction, ejection fraction of 23%, with mild enlarged left ventricle. The 12-lead ECG showed atrial fibrillation with a mean heart rate of about 100 bpm, QRS duration 160 ms, QT interval 400 ms, right bundle branch block (RBBB) and left anterior fascicular block (LAFB). The combination of RBBB features in the precordial leads and LAFB features in the limb leads is known as ''masquerading bundle branch block''. In most cases of RBBB and LAFB, the QRS axis deviation is located between - 80 to -120 degrees. Rarely, when predominant left ventricular forces are present, the QRS axis deviation is near about -90 degrees, turning the pattern into an atypical form. In a situation of RBBB associated with LAFB, the S wave can be absent or very small in lead I. Such a situation is the result of not only purely LAFB but also with left ventricular hypertrophy and/or focal block due to scar (extensive anterior myocardial infarction) or fibrosis (cardiomyopathy). Sometimes, this specific ECG pattern is mistaken for LBBB. RBBB with LAFB may imitate LBBB either in the limb leads (known as 'standard masquerading' - absence of S wave in lead I), or in the precordial leads (called 'precordial masquerading' - absence of S wave in leads V₅ and V₆). Our ECG showed both these types of masquerading bundle branch block - absence of S wave in lead I and in leads V₅ and V₆. |
12,210 | Cardiac acceleration at the onset of exercise: a potential parameter for monitoring progress during physical training in sports and rehabilitation. | There is a need for easy-to-use methods to assess training progress in sports and rehabilitation research. The present review investigated whether cardiac acceleration at the onset of physical exercise (HRonset) can be used as a monitoring variable. The digital databases of Scopus and PubMed were searched to retrieve studies investigating HRonset. In total 652 studies were retrieved. These articles were then classified as having emphasis on HRonset in a sports or rehabilitation setting, which resulted in 8 of 112 studies with a sports application and 6 of 68 studies with a rehabilitation application that met inclusion criteria. Two co-existing mechanisms underlie HRonset: feedforward (central command) and feedback (mechanoreflex, metaboreflex, baroreflex) control. A number of studies investigated HRonset during the first few seconds of exercise (HRonsetshort), in which central command and the mechanoreflex determine vagal withdrawal, the major mechanism by which heart rate (HR) increases. In subsequent sports and rehabilitation studies, interest focused on HRonset during dynamic exercise over a longer period of time (HRonsetlong). Central command, mechanoreflexes, baroreflexes, and possibly metaboreflexes contribute to HRonset during the first seconds and minutes of exercise, which in turn leads to further vagal withdrawal and an increase in sympathetic activity. HRonset has been described as the increase in HR compared with resting state (delta HR) or by exponential modeling, with measurement intervals ranging from 0-4 s up to 2 min. Delta HR was used to evaluate HRonsetshort over the first 4 s of exercise, as well as for analyzing HRonsetlong. In exponential modeling, the HR response to dynamic exercise is biphasic, consisting of fast (parasympathetic, 0-10 s) and slow (sympathetic, 1-4 min) components. Although available studies differed largely in measurement protocols, cross-sectional and longitudinal training studies showed that studies analyzing HRonset in relation to physical training primarily incorporated HRonsetlong. HRonsetlong slowed in athletes as well as in patients with a coronary disease, who have a relatively fast HRonsetlong. It is advised to include both HRonsetlong and HRonsetshort in further studies. The findings of this review suggest that HRonset is a potential tool for monitoring and titrating training in sports as well as in rehabilitation settings, particularly in patients with ventricular fibrillation. Monitoring HRonset in the early phase of training can help optimize the effectiveness of training and therapy. More research is needed to gain a better understanding of the mechanisms underlying HRonset in relation to their application in sports and rehabilitation settings. |
12,211 | Multidetector computed tomography may be an adequate screening test to reduce periprocedural stroke in atrial fibrillation ablation: a multicenter propensity-matched analysis. | Whether routine transesophageal echocardiography (TEE) in addition to multidetector computed tomography (MDCT) has incremental value in preventing periprocedural stroke before atrial fibrillation (AF) ablation is unclear.</AbstractText>The purpose of this study was to evaluate whether screening with MDCT is sufficient for preventing periprocedural stroke.</AbstractText>From 4 tertiary centers, we enrolled 1147 patients (902 males, age 57 ± 11 years) with optimal anticoagulation and preserved left ventricular ejection function who had undergone MDCT and routine TEE (group 1, n = 678) or selective TEE (group 2, n = 469) as screening tests before AF ablation. Based on a propensity score analysis, 2 groups with 412 matched pairs were created.</AbstractText>Patient baseline characteristics were comparable between the matched groups. In group 1 (n = 412), thrombi were detected in 4 patients (1.0%) on TEE, and ablation was not performed. These patients also showed thrombi (n = 3) or blood stasis (n = 1) on MDCT. For thrombi detection, MDCT had sensitivity and negative predictive value of 100%. In group 2 (n = 412), thrombi were detected in 7 patients (1.7%) on MDCT. Of these patients , 2 (0.5%) also showed thrombi on TEE. Periprocedural stroke incidence did not differ between the groups (0.2% each, P = 1.0).</AbstractText>The incidence of periprocedural stroke was low and did not differ significantly between the group assigned to routine TEE vs selective TEE screening in AF patients undergoing anticoagulation therapy if the patients had conditions associated with low thrombus risk. Thus, preprocedural TEE may not be necessary before AF ablation in patients who have undergone preprocedural cardiac MDCT that shows no evidence of left atrial appendage thrombus.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,212 | A temporal window of vulnerability for development of atrial fibrillation with advancing heart failure. | Heart failure (HF) is associated with development of AF and life-threatening ventricular tachycardia and fibrillation (VT/VF). Vulnerability to development of AF and VT/VF at different stages of HF and the underlying pathophysiological mechanisms are poorly defined. The present study was designed to determine the time-course of development of electrical and structural remodelling of the atria and ventricles, and their contribution to induction of AF and VT/VF in a canine model of HF.</AbstractText>Dogs were ventricular tachypaced (VTP) for 2-3 weeks or 5-6 weeks ('early' and 'late' HF, respectively). Electrophysiological studies were performed in isolated atrial and ventricular preparations and correlated with cardiac dimensions and haemodynamic parameters recorded in vivo. Vulnerability to programmed electrical stimulation-induced AF was greater in early vs. late stages of HF (78% vs. 38%). In contrast, VT/VF was inducible in late but not in early stages of HF (38% vs. 0%). The temporal distinction in atrial and ventricular arrhythmia susceptibility was associated with a much more rapid development of electrical and structural remodelling in atria. Vulnerability to AF developed following moderate electro-structural remodelling and waned with further progression to severe remodelling, which averted rapid atrial activation.</AbstractText>A temporal window of vulnerability for AF appears relatively early during development of VTP-induced HF in dogs, whereas VT/VF vulnerability is observed at more advanced stages of HF. These findings, if confirmed in humans, may have clinical implications with regard to prognosis and approach to therapy of patients with HF.</AbstractText>© 2014 The Authors. European Journal of Heart Failure © 2014 European Society of Cardiology.</CopyrightInformation> |
12,213 | Mechanism of reentry induction by a 9-V battery in rabbit ventricles. | Although the application of a 9-V battery to the epicardial surface is a simple method of ventricular fibrillation induction, the fundamental mechanisms underlying this process remain unstudied. We used a combined experimental and modelling approach to understand how the interaction of direct current (DC) from a battery may induce reentrant activity within rabbit ventricles and its dependence on battery application timing and duration. A rabbit ventricular computational model was used to simulate 9-V battery stimulation for different durations at varying onset times during sinus rhythm. Corresponding high-resolution optical mapping measurements were conducted on rabbit hearts with DC stimuli applied via a relay system. DC application to diastolic tissue induced anodal and cathodal make excitations in both simulations and experiments. Subsequently, similar static epicardial virtual electrode patterns were formed that interacted with sinus beats but did not induce reentry. Upon battery release during diastole, break excitations caused single ectopics, similar to application, before sinus rhythm resumed. Reentry induction was possible for short battery applications when break excitations were slowed and forced to take convoluted pathways upon interaction with refractory tissue from prior make excitations or sinus beats. Short-lived reentrant activity could be induced for battery release shortly after a sinus beat for longer battery applications. In conclusion, the application of a 9-V battery to the epicardial surface induces reentry through a complex interaction of break excitations after battery release with prior induced make excitations or sinus beats. |
12,214 | Heart failure highlights in 2012-2013. | Heart failure has become the cardiovascular epidemic of the century. The European Journal of Heart Failure is dedicated to the advancement of knowledge in the field of heart failure management. In 2012 and 2013, several pioneering scientific discoveries and paradigm-shifting clinical trials have been published. In the current paper, we will discuss the most significant novel insights into the pathophysiology, diagnosis, and treatment of heart failure that were published during this period. All relevant research areas are discussed, including pathophysiology, co-morbidities, arrhythmias, biomarkers, clinical trials, and device therapy, including left ventricular assist devices. |
12,215 | Evaluation of repolarization dynamics using the QT-RR regression line slope and intercept relationship during 24-h Holter ECG. | QT-RR linear regression consists of two parameters, slope and intercept, and the aim of this study was to evaluate repolarization dynamics using the QT-RR linear regression slope and intercept relationship during 24-h Holter ECG. This study included 466 healthy subjects (54.6 ± 14.6 years; 200 men and 266 women) and 17 patients with ventricular arrhythmias, consisted of 10 patients with idiopathic ventricular fibrillation (IVF) and 7 patients with torsades de pointes (TDP). QT and RR intervals were measured from ECG waves based on a 15-s averaged ECG during 24-h Holter recording using an automatic QT analyzing system. The QT interval dependence on the RR interval was analyzed using a linear regression line for each subject ([QT] = A[RR] + B; where A is the slope and B is the y-intercept). The slope of the QT-RR regression line in healthy subjects was significantly greater in women than in men (0.185 ± 0.036 vs. 0.161 ± 0.033, p < 0.001) and the intercept was significantly smaller in women than in men (0.229 ± 0.028 vs. 0.240 ± 0.027, p < 0.001). A scatter diagram of the QT-RR regression line slope and intercept among healthy subjects demonstrated a statistically significant negative correlation (B = -0.62A + 0.34, r = -0.79). Distribution of both scatter diagrams of the slope and the intercept of the QT-RR regression line in patients with IVF and TDP was different from healthy subjects (left corner for IVF and upward shift for TDP). The slope and intercept relationship of the QT-RR linear regression line based on 24-h Holter ECG may become a simple useful marker for abnormality of ventricular repolarization dynamics. |
12,216 | Circumstances and outcomes of out-of-hospital cardiac arrest in elementary and middle school students in the era of public-access defibrillation. |  Circumstances and outcomes of out-of-hospital cardiac arrest (OHCA) in elementary and middle school students while at school in the era of public-access defibrillation are unknown.</AbstractText> We conducted a nationwide hospital-based survey of elementary and middle school students who had had OHCA of cardiac origin and received prehospital resuscitation in 2005-2009. Among 58 cases recruited, 90% were witnessed by bystanders; 86% had ventricular fibrillation as the initial rhythm; 74% were resuscitated by bystanders; 24% were defibrillated by bystanders; 55% occurred at school; 66% were exercise-related; 48% were followed up before the event; 67% had structural heart disease. In total, 53% of overall patients and 79% of those initially defibrillated by bystanders had a favorable neurological outcome. Patients were more likely to be defibrillated by bystanders (38% vs. 8%, P=0.012) and had a more favorable neurological outcome in schools (69% vs. 35%, P=0.017) than in other locations. The majority of arrests in schools were exercise-related (84% vs. 42%, P=0.001), occurred at sports venues, and students were resuscitated by teachers; half of the cases at school occurred in patients with a pre-event follow-up.</AbstractText> After OHCA, children were more likely to be defibrillated by bystanders and had a better outcome in schools than in other locations, which may be relevant to the circumstances of events. </AbstractText> |
12,217 | [Current indications for an implantable cardioverter defibrillator (ICD)]. | Sudden cardiac death is one of the leading causes of death in industrialized countries. The implantable cardioverter/defibrillator (ICD) is the most effective treatment for malignant ventricular tachyarrhythmias. Current guidelines recommend the implantation of a defibrillator in patients who experienced ventricular tachycardia or fibrillation (secondary prevention of sudden cardiac death), as well as in high risk patients for primary prevention. The latter are patients with impaired left ventricular function ≤ 35 %. With the exception of secondary prevention indications (ie. after a "survived sudden cardiac death") indications for ICD implantation in the context of other cardiomyopathies, such as hypertrophic (obstructive) cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy (ARVC), and of channelopathies, such as Brugada syndrome and long QT syndrome are complex. Before deciding to implant an ICD, the indication as well as the potential complications (inappropriate shocks, risk of infection, device or lead replacement, costs, etc.) have to be considered and discussed in detail with the patients and their relatives. There are very few specific hazards or significant limitations in daily life for the patient and his environment caused by the ICD. An ICD can be transiently deactivated if necessary by using a magnet (eg. during surgery) or permanently deactivated by re-programming the device (eg. palliative care).</Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Arenja</LastName><ForeName>Nisha</ForeName><Initials>N</Initials><AffiliationInfo><Affiliation>Kardiologie/Elektrophysiologie, Universitätsspital Basel.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Schaer</LastName><ForeName>Beat</ForeName><Initials>B</Initials><AffiliationInfo><Affiliation>Kardiologie/Elektrophysiologie, Universitätsspital Basel.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Sticherling</LastName><ForeName>Christian</ForeName><Initials>C</Initials><AffiliationInfo><Affiliation>Kardiologie/Elektrophysiologie, Universitätsspital Basel.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Kühne</LastName><ForeName>Michael</ForeName><Initials>M</Initials><AffiliationInfo><Affiliation>Kardiologie/Elektrophysiologie, Universitätsspital Basel.</Affiliation></AffiliationInfo></Author></AuthorList><Language>ger</Language><PublicationTypeList><PublicationType UI="D004740">English Abstract</PublicationType><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D016454">Review</PublicationType></PublicationTypeList><VernacularTitle>Aktuelle Indikationen für einen implantierbaren Defibrillator.</VernacularTitle></Article><MedlineJournalInfo><Country>Switzerland</Country><MedlineTA>Ther Umsch</MedlineTA><NlmUniqueID>0407224</NlmUniqueID><ISSNLinking>0040-5930</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D009202" MajorTopicYN="N">Cardiomyopathies</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D016757" MajorTopicYN="N">Death, Sudden, Cardiac</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017147" MajorTopicYN="Y">Defibrillators, Implantable</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D019317" MajorTopicYN="N">Evidence-Based Medicine</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006333" MajorTopicYN="N">Heart Failure</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D017180" MajorTopicYN="N">Tachycardia, Ventricular</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D018487" MajorTopicYN="N">Ventricular Dysfunction, Left</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D014693" MajorTopicYN="N">Ventricular Fibrillation</DescriptorName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading></MeshHeadingList><OtherAbstract Type="Publisher" Language="ger">Der plötzliche Herztod gehört zu den häufigsten Todesursachen in den Industrieländern. Der implantierbare Cardioverter/Defibrillator (ICD) stellt die effektivste Therapie zur Behandlung lebensbedrohlicher ventrikulärer Tachyarrhythmien dar. Die aktuellen Richtlinien empfehlen die Implantation eines Defibrillators zur Sekundärprävention bei Patienten mit ventrikulärer Tachykardie oder Kammerflimmern sowie zur Primärprävention bei Hochrisikopatienten. Jene sind Patienten mit einer eingeschränkten linksventrikulären Pumpfunktion ≤ 35 %. Bei anderen Kardiomyopathien, wie der hypertrophen Kardiomyopathie oder der arrhythmogenen rechtsventrikulären Kardiomyopathie (ARVC), sowie bei Ionenkanalerkrankungen wie dem Brugada-Syndrom oder dem Long-QT-Syndrom sind die Indikationen abgesehen von der Sekundärprävention komplex und stetigem Wandel unterworfen. Jede mögliche Indikation einer ICD-Implantation, sowie die damit möglicherweise verbundenen Komplikationen (inadäquate Schocks, Infektionsgefahr, Aggregat- oder Elektrodendysfunktion, Kosten, etc.) müssen im Voraus ausführlich mit dem Patienten und den Angehörigen diskutiert werden. Für die meisten Patienten mit ICD sowie ihr Umfeld entstehen durch das Gerät nur wenige relevante Einschränkungen im Alltag. ICDs können bei Bedarf durch Auflage eines Magneten vorübergehend (z. B. im Rahmen einer Operation) oder auf Wunsch durch Umprogrammieren des Geräts permanent ausgeschaltet werden (z. B. bei Palliation). |
12,218 | Dominant frequency increase rate predicts transition from paroxysmal to long-term persistent atrial fibrillation. | Little is known about the mechanisms underlying the transition from paroxysmal to persistent atrial fibrillation (AF). In an ovine model of long-standing persistent AF we tested the hypothesis that the rate of electric and structural remodeling, assessed by dominant frequency (DF) changes, determines the time at which AF becomes persistent.</AbstractText>Self-sustained AF was induced by atrial tachypacing. Seven sheep were euthanized 11.5±2.3 days after the transition to persistent AF and without reversal to sinus rhythm; 7 sheep were euthanized after 341.3±16.7 days of long-standing persistent AF. Seven sham-operated animals were in sinus rhythm for 1 year. DF was monitored continuously in each group. Real-time polymerase chain reaction, Western blotting, patch clamping, and histological analyses were used to determine the changes in functional ion channel expression and structural remodeling. Atrial dilatation, mitral valve regurgitation, myocyte hypertrophy, and atrial fibrosis occurred progressively and became statistically significant after the transition to persistent AF, with no evidence for left ventricular dysfunction. DF increased progressively during the paroxysmal-to-persistent AF transition and stabilized when AF became persistent. Importantly, the rate of DF increase correlated strongly with the time to persistent AF. Significant action potential duration abbreviation, secondary to functional ion channel protein expression changes (CaV1.2, NaV1.5, and KV4.2 decrease; Kir2.3 increase), was already present at the transition and persisted for 1 year of follow up.</AbstractText>In the sheep model of long-standing persistent AF, the rate of DF increase predicts the time at which AF stabilizes and becomes persistent, reflecting changes in action potential duration and densities of sodium, L-type calcium, and inward rectifier currents.</AbstractText> |
12,219 | Miniaturized mechanical chest compressor improves calculated cerebral perfusion pressure without compromising intracranial pressure during cardiopulmonary resuscitation in a porcine model of cardiac arrest. | One of the major goals of cardiopulmonary resuscitation (CPR) is to provide adequate oxygen delivery to the brain for minimizing cerebral injury resulted from cardiac arrest. The optimal chest compression during CPR should effectively improve brain perfusion without compromising intracranial pressure (ICP). Our previous study has demonstrated that the miniaturized mechanical chest compressor improved hemodynamic efficacy and the success of CPR. In the present study, we investigated the effects of the miniaturized chest compressor (MCC) on calculated cerebral perfusion pressure (CerPP) and ICP.</AbstractText>Ventricular fibrillation was electrically induced and untreated for 7min in 13 male domestic pigs weighing 39±3kg. The animals were randomized to receive mechanical chest compression with the MCC (n=7), or the Thumper device (n=6). CPR was performed for 5min before defibrillation attempt by a single 150J shock. At 2.5min of CPR, the epinephrine at a dose of 20μg/kg was administered. Additional epinephrine was administered at an interval of 3min thereafter. If resuscitation was not successful, CPR was resumed for an additional 2min prior to the next defibrillation until successful resuscitation or for a total of 15min. Post-resuscitated animals were observed for 2h.</AbstractText>Significantly greater intrathoracic positive and negative pressures during compression and decompression phases of CPR were observed with the MCC when compared with the Thumper device. The MCC produced significantly greater coronary perfusion pressure and end-tidal carbon dioxide. There were no statistically significant differences in systolic and mean ICP between the two groups; however, both of the measurements were slightly greater in the MCC treated animals. Interestingly, the diastolic ICP was significantly lower in the MCC group, which was closely related to the significantly lower negative intrathoracic pressure in the animals that received the MCC. Most important, systolic, diastolic and mean calculated CerPP were all significantly greater in the animals receiving the MCC.</AbstractText>In the present study, mechanical chest compression with the MCC significantly improved calculated CerPP but did not compromise ICP during CPR. It may provide a safe and effective chest compression during CPR. Protocol number: P1205.</AbstractText>Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,220 | Atrial fibrillation from the pathologist's perspective. | Atrial fibrillation (AF), the most common sustained cardiac arrhythmia encountered in clinical practice, is associated with increased morbidity and mortality. Electrophysiologically, it is characterized by a high rate of asynchronous atrial cell depolarization causing a loss of atrial contractile function and irregular ventricular rates. For a long time, AF was considered as a pure functional disorder without any structural background. Only in recent years, have new mapping and imaging techniques identified atrial locations, which are very often involved in the initiation and maintenance of this supraventricular arrhythmia (i.e. the distal portion of the pulmonary veins and the surrounding atrial myocardium). Morphological analysis of these myocardial sites has demonstrated significant structural remodeling as well as paved the way for further knowledge of AF natural history, pathogenesis, and treatment. This architectural myocardial disarrangement is induced by the arrhythmia itself and the very frequently associated cardiovascular disorders. At the same time, the structural remodeling is also capable of sustaining AF, thereby creating a sort of pathogenetic vicious circle. This review focuses on current understanding about the structural and genetic bases of AF with reference to their classification, pathogenesis, and clinical implications. |
12,221 | Double simultaneous defibrillators for refractory ventricular fibrillation. | Out-of-hospital cardiac arrest is a leading cause of death in the United States. Ventricular fibrillation (VF) is the most common initial rhythm after cardiac arrest.</AbstractText>To describe a novel approach to the patient with intractable VF after cardiac arrest.</AbstractText>A 51-year old man presented in cardiac arrest after a ST-elevation myocardial infarction. He remained in VF despite receiving typical therapy including cardiopulmonary resuscitation, amiodarone, lidocaine, epinephrine, and five attempts at defibrillation with 200 J using a biphasic defibrillator. VF was eventually terminated with 400 J by the simultaneous use of two biphasic defibrillators. The patient had a full recovery.</AbstractText>We present a case and supportive literature for a novel treatment of high-energy defibrillation in a patient with refractory VF.</AbstractText>Copyright © 2014 Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,222 | Risk factors for progression of functional tricuspid regurgitation. | The aim of this study was to determine the risk factors for tricuspid regurgitation (TR) progression in a contemporary population of patients referred for echocardiography. In a case-control study, we compared 100 consecutive patients with TR progression on serial echocardiograms (trivial or mild TR on the first echocardiogram and moderate or severe functional TR on a follow-up echocardiogram) with 100 patients matched for age and gender, having mild TR at baseline and no TR progression. Mean age was 72 ± 10 years, 55% were males, and time to TR progression was 5.3 ± 2.9 years. Less than 10% had rheumatic heart disease. Left ventricular ejection fraction was preserved (≥50%) in 85% of the TR progression group and in 74% of the control group (p = 0.06). Pulmonary artery systolic pressure increased from 41 ± 16 to 56 ± 18 mm Hg in the TR progression group and decreased from 44 ± 13 to 41 ± 11 mm Hg in the control group (p <0.0001). Independent risk factors for TR progression were pulmonary artery systolic pressure change during follow-up (odds ratio per 1 mm Hg 1.14, 95% confidence interval 1.06 to 1.23, p <0.0001), permanent atrial fibrillation (odds ratio 14.3, 95% confidence interval 4.6 to 44.2, p <0.0001), and coronary artery disease (odds ratio 5.7, 95% confidence interval 1.4 to 22.8, p = 0.015). All-cause mortality at 3 years was 20% for patients without TR progression, 42% for moderate TR, and 63% for severe TR, p <0.0001. Progression-to-severe TR independently predicted subsequent mortality. In conclusion, in patients with low prevalence of rheumatic heart disease and preserved left ventricular ejection fraction, pulmonary artery systolic pressure increase and permanent atrial fibrillation were the most powerful risk factors for TR progression. Progression-to-severe TR was an independent predictor of subsequent mortality. |
12,223 | Radiofrequency catheter ablation of atypical atrial flutter in dogs. | Five dogs were presented to our institution for fatigue caused by an incessant supraventricular tachycardia. In all dogs, an ECG on admission showed a narrow QRS complex tachycardia with a median ventricular cycle length of 220 ms (range 180-360 ms), and a positive atrial depolarization identifiable in the ST segment following the previous QRS complex. There was a 1:1 atrioventricular conduction ratio in all but one dog, which presented with 2:1 atrioventricular block. Electrophysiologic studies identified the underlying arrhythmogenic mechanism as a right atrial macro-reentrant tachycardia with two distinct isthmic areas: right septal (RS) in three dogs and right atrial free wall (RAFW) in two dogs. Linear radiofrequency catheter ablation was performed during tachycardia in all dogs at the identified isthmic area, which acutely blocked the macroreentrant circuit. At 18-month follow-up, 3 dogs (1 with RAFW isthmus and 2 with RS isthmus) showed no recurrence of the arrhythmia on Holter monitoring. One dog with RS isthmus showed recurrence of the supraventricular tachycardia 15 days post-ablation, and 1 dog with RAFW isthmus presented with persistent atrial fibrillation 2 months post-ablation. |
12,224 | Very early recurrence of Takotsubo syndrome. | An 82-year-old female presented lasting chest pain for stimulation and the ECG revealed ventricular fibrillation and ST segment elevation, so we considered acute myocardial infarction. However, after the clinical condition of the patient improved, symptoms recurred for stimulation again on day 4. An echocardiogram showed left ventricular apical ballooning, so, we diagnosed her as Takotsubo syndrome. |
12,225 | Effect of mitral inflow pattern on diagnosis of severe mitral regurgitation in patients with chronic organic mitral regurgitation. | To determine sensitivity and specificity of E wave velocity in patients with severe chronic organic mitral regurgitation (MR) and normal left ventricular ejection fraction (EF) and to evaluate prevalence of A wave dominance in patients with severe MR.</AbstractText>We compared 35 patients with quantified severe, chronic, quantified, organic MR due to flail/prolapsed leaflets who had reparative surgery with 35 age-matched control subjects.</AbstractText>EF < 60%, atrial fibrillation, and more than mild aortic regurgitation.</AbstractText>Mean [standard deviation (SD)] age [70 (8) years vs. 69 (8) years; p = 0.94] and mean (SD) EF [66% (6%) vs. 65% (4%); p = 0.43] were not different between the two groups. Mean (SD) E wave velocity was greater in case patients than control subjects [1.2 (0.3) m/sec vs. 0.7 (0.15) m/sec; p < 0.001]. However, E wave velocity of 1.2 m/sec had a sensitivity of only 57% [95% confidence interval (CI), 41-7 and a specificity of 100% (95% CI, 90-100%) in identifying severe MR. E wave velocity of 0.9 m/sec had a more optimal combined sensitivity (89%; 95% CI, 74-95%) and specificity (86%; 95% CI, 71-94%). A wave dominance was seen in 18% of case patients and 66% of control subjects (p < 0.001).</AbstractText>E wave velocity of 1.2 m/sec is specific not sensitive for severe organic MR; E wave velocity of 0.9 m/sec has better sensitivity and specificity. A wave dominance pattern alone cannot exclude patients with severe organic MR. Our findings highlight the importance of a comprehensive echocardiographic exam rather than relying on a few Doppler parameters in diagnosing MR.</AbstractText> |
12,226 | Cardiac contractility modulation increases action potential duration dispersion and decreases ventricular fibrillation threshold via β1-adrenoceptor activation in the crystalloid perfused normal rabbit heart. | <AbstractText Label="BACKGROUND/OBJECTIVES" NlmCategory="OBJECTIVE">Cardiac contractility modulation (CCM) is a new treatment being developed for heart failure (HF) involving application of electrical current during the absolute refractory period. We have previously shown that CCM increases ventricular force through β1-adrenoceptor activation in the whole heart, a potential pro-arrhythmic mechanism. This study aimed to investigate the effect of CCM on ventricular fibrillation susceptibility.</AbstractText>Experiments were conducted in isolated New Zealand white rabbit hearts (2.0-2.5 kg, n=25). The effects of CCM (± 20 mA, 10 ms phase duration) on the left ventricular basal and apical monophasic action potential duration (MAPD) were assessed during constant pacing (200 bpm). Ventricular fibrillation threshold (VFT) was defined as the minimum current required to induce sustained VF with rapid pacing (30 × 30 ms). Protocols were repeated during perfusion of the β1-adrenoceptor antagonist metoprolol (1.8 μM). In separate hearts, the dynamic and spatial electrophysiological effects of CCM were assessed using optical mapping with di-4-ANEPPS.</AbstractText>CCM significantly shortened MAPD close to the stimulation site (Basal: 102 ± 5 [CCM] vs. 131 ± 6 [Control] ms, P<0.001). VFT was reduced during CCM (2.6 ± 0.6 [CCM] vs. 6.1 ± 0.8 [Control] mA, P<0.01) and was correlated (r(2)=0.40, P<0.01) with increased MAPD dispersion (26 ± 4 [CCM] vs. 5 ± 1 [Control] ms, P<0.01) (n=8). Optical mapping revealed greater spread of CCM induced MAPD shortening during basal vs. apical stimulation. CCM effects were abolished by metoprolol and exogenous acetylcholine. No evidence for direct electrotonic modulation of APD was found, with APD adaptation occurring secondary to adrenergic stimulation.</AbstractText>CCM decreases VFT in a manner associated with increased MAPD dispersion in the crystalloid perfused normal rabbit heart.</AbstractText>Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.</CopyrightInformation> |
12,227 | Outcome of prolonged ventricular fibrillation and CPR in a rat model of chronic ischemic left ventricular dysfunction. | Patients with chronic left ventricular (LV) dysfunction are assumed to have a lower chance of successful CPR and lower likelihood of ultimate survival. However, these assumptions have rarely been documented. Therefore, we investigated the outcome of prolonged ventricular fibrillation (VF) and CPR in a rat model of chronic LV dysfunction. Sprague-Dawley rats were randomized to (1) chronic LV dysfunction: animals underwent left coronary artery ligation; and (2) sham control. Echocardiography was used to measure cardiac performance before surgery and 4 weeks after surgery. Four weeks after surgical intervention, 8 min of VF was induced and defibrillation was delivered after 8 min of CPR. LV dilation and low ejection fraction were observed 4 weeks after coronary ligation. With optimal chest compressions, coronary perfusion pressure values during CPR were well maintained and indistinguishable between groups. There were no differences in resuscitability and numbers of shock required for successful resuscitation between groups. Despite the significantly decreased cardiac index in LV dysfunction animals before induction of VF, no differences in cardiac index were observed between groups following resuscitation, which was associated with the insignificant difference in postresuscitation survival. In conclusion, the outcomes of CPR were not compromised by the preexisting chronic LV dysfunction. |
12,228 | 3DQRS: a method to obtain reliable QRS complex detection within high field MRI using 12-lead electrocardiogram traces. | To develop a technique that accurately detects the QRS complex in 1.5 Tesla (T), 3T, and 7T MRI scanners.</AbstractText>During early systole, blood is rapidly ejected into the aortic arch, traveling perpendicular to the MRI's main field, which produces a strong voltage (V(MHD)) that eclipses the QRS complex. Greater complexity arises in arrhythmia patients, since V(MHD) varies between sinus-rhythm and arrhythmic beats. The 3DQRS method uses a kernel consisting of 6 electrocardiogram (ECG) precordial leads (V1-V6), compiled from a 12-lead ECG performed outside the magnet. The kernel is cross-correlated with signals acquired inside the MRI to identify the QRS complex in real time. The 3DQRS method was evaluated against a vectorcardiogram (VCG)-based approach in two premature ventricular contraction (PVC) and two atrial fibrillation (AF) patients, a healthy exercising athlete, and eight healthy volunteers, within 1.5T and 3T MRIs, using a prototype MRI-conditional 12-lead ECG system. Two volunteers were recorded at 7T using a Holter recorder.</AbstractText>For QRS complex detection, 3DQRS subject-averaged sensitivity levels, relative to VCG were: 1.5T (100% versus 96.7%), 3T (98.9% versus 92.2%), and 7T (96.2% versus 77.7%).</AbstractText>The 3DQRS method was shown to be more effective in cardiac gating than a conventional VCG-based method.</AbstractText>Copyright © 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
12,229 | Devices for mitral valve repair. | The natural history of severe mitral regurgitation (MR) is unfavorable, leading to left ventricular failure, atrial fibrillation, stroke, and death. Many patients affected by severe regurgitation (MR) do not currently undergo surgery, mainly due to the perceived risk of the procedure (old age, impaired left ventricular function, and comorbidities). Mitral transcatheter interventions carry the hope of minimizing risks while preserving clinical efficacy of surgical repair, as an alternative to conventional treatment. Multiple technologies and diversified approaches are under development with the purpose of treating MR in less invasive ways. They can be categorized based on the anatomical and patho-physiological addressed target. Among them, MitraClip (Abbott Vascular, Inc., Menlo Park, California) has emerged as a clinically safe and effective method for percutaneous mitral valve repair in patients either with degenerative and functional regurgitation. This device mimics the surgical edge-to-edge repair initially described by Alfieri in the early 1990s. Other repair technologies include percutaneous direct and indirect annuloplasty, neochordae implantation, and left ventricular reshaping. They are still in early phase clinical trials or preclinical studies. The combination of different repair techniques is likely to be required to achieve good long-lasting results. In the future, novel devices, improved knowledge, more efficient imaging, and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated, as well as improve the results both in terms of early efficacy and long-term durability. These treatments are currently reserved to high-risk and inoperable patients, and their application requires an integrated Heart-Team approach. They represent the natural evolution of surgery and promise to expand treatment options and improve patients' outcomes in the near future. |
12,230 | Safety and tolerability of regadenoson CMR. | Knowledge of adverse events associated with regadenoson perfusion cardiac magnetic resonance (CMR) and patient tolerability has implications for patient safety and staff training. We sought to assess the safety and tolerability of regadenoson stress CMR.</AbstractText>A group of 728 consecutive patients (median age 58, 44% female) and 25 normal volunteers (median age 21, 24% female) were recruited from August 2009 to March 2012 using a prospective, cross-sectional study design. Subjects were stressed using fixed-dose regadenoson and imaged using a 1.5T MRI scanner. Symptoms and adverse events including death, myocardial infarction (MI), ventricular tachycardia (VT)/ventricular fibrillation (VF), hospitalization, arrhythmias, and haemodynamic stability were assessed.</AbstractText>There were no occurrences of death, MI, VT/VF, high-grade atrioventricular block, or stress-induced atrial fibrillation. Notable adverse events included one case of bronchospasm and one case of heart failure exacerbation resulting in hospitalization. The most common symptoms in patients were dyspnoea (30%, n = 217), chest discomfort (27%, n = 200), and headache (15%, n = 111). There was minimal change between baseline and peak systolic and diastolic blood pressure in both patients and volunteers (P > 0.05). A blunted heart rate response to regadenoson was noted in patients with body mass index (BMI) ≥ 30 kg/m(2) (P < 0.001), and diabetes (P = 0.001).</AbstractText>Regadenoson CMR is well tolerated and can be performed safely with few adverse events.</AbstractText>© The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.</CopyrightInformation> |
12,231 | Cardiac sarcoidosis: the Christchurch experience. | To present an overview of the diagnosis, treatment and outcomes of patients with cardiac sarcoidosis managed in Christchurch Hospital, New Zealand.</AbstractText>A retrospective review of patients with cardiac sarcoidosis at Christchurch Hospital from January 2005 to December 2012.</AbstractText>Eighteen patients were identified with cardiac sarcoidosis. All the 12 patients that underwent cardiac magnetic resonance imaging (CMR) had abnormal scans. Angiotensin-converting enzyme (ACE) levels were elevated in 4 of 16 patients and troponin (cTn) was elevated in 5 of 15 patients. Endomyocardial biopsies were diagnostic in two of six patients. The principal causes for presentation related to symptomatic high-grade atrioventricular conduction block and congestive heart failure with six patients in each of these groups. In addition, three patients presented with ventricular tachycardia and the remaining three patients presented with atrial fibrillation, recurrent presyncope without proven heart block and an asymptomatic persistent elevation of cardiac troponin. Seven patients had pre-existing, extra-cardiac sarcoidosis and a concomitant diagnosis was made in a further eight cases. Three patients had isolated cardiac involvement at presentation. Sixteen patients received immunosuppressive therapy. Twelve patients had cardiac devices implanted; five pacemakers, five defibrillators and two resynchronising pacemaker defibrillators. During follow up for 0.1-30.8 years, median 4.8 years, two patients died.</AbstractText>In our patients CMR demonstrated high diagnostic sensitivity, while biomarkers (ACE and cTn) were frequently within the normal reference range. Cardiac sarcoidodis caused major arrhythmias or heart failure in the majority of patients. Most patients were treated with immunosuppression and cardiac device therapy. Long-term mortality was lower than previously reported.</AbstractText>© 2013 The Authors; Internal Medicine Journal © 2013 Royal Australasian College of Physicians.</CopyrightInformation> |
12,232 | The QT prolongation and clinical features in patients with takotsubo cardiomyopathy: Experiences of two tertiary cardiovascular centers. | There are few data regarding clinical characteristics, laboratory parameters, electrocardiographic and echocardiographic findings in takotsubo cardiomyopathy patients presenting with QT prolongation. Aim of this study was to investigate the differences in these parameters between takotsubo cardiomyopathy patients presenting with and those without QT prolongation.</AbstractText>We performed an observational retrospective study. One hundred five patients were enrolled from the takotsubo cardiomyopathy registry database and divided according to the presence of QT prolongation. Fifty patients presented with QT prolongation (QT group) and 55 did not (NQT group). Statistical analysis was performed using Student's t-test or Mann-Whitney U test and chi-square test.</AbstractText>QT group had higher prevalence of dyspnea (66 versus 40%, p=0.008) and cardiogenic shock (46 versus 24%, p=0.016) than NQT group. QT group had higher prevalence of ST elevation (82 versus 64%, p=0.036), T wave inversion (96 versus 58%, p=0.001), ventricular tachycardia/ventricular fibrillation (8 versus 0%, p=0.032) and classic ballooning pattern (92 versus 66%, p=0.003), but lower left ventricular ejection fraction (mean, 39.2 versus 43.5%, p=0.005). In addition, QT group had significant higher hs-C-reactive protein (median, 6.6 versus 1.7 mg/L, p=0.023), creatine kinase-MB (median, 18.6 versus 7.6 ng/mL, p=0.032) and NT-pro-brain natriuretic peptide levels (median, 3637 versus 2145 pg/mL, p=0.044). QT group required more frequent use of inotropics (46 versus 24%, p=0.016) and diuretics (58 versus 38%, p=0.042) than NQT group.</AbstractText>The clinical features of takotsubo cardiomyopathy are different according to the presence of QT prolongation. The QT group was lesser likely to have preserved cardiovascular reserve and more likely to require hemodynamic support than the NQT group despite the entire prognosis of takotsubo cardiomyopathy is excellent regardless of QT prolongation.</AbstractText> |
12,233 | [Cardiac resynchronization therapy in patients with heart failure: a 10-year experience]. | Multiple randomized trials support the clinical benefits of cardiac resynchronization therapy (CRT) in patients with heart failure (HF) and ventricular dyssynchrony. Since the year 2000 this therapy has been increasingly used in Chile.</AbstractText>To describe the clinical characteristics and follow-up of HF patients undergoing CRT in a single Chilean university hospital during the last 10 years.</AbstractText>All patients undergoing CRT between 2000 and 2010 in our university hospital were included. Clinical and echocardiographic data were extracted from medical records and mortality causes were obtained from the National Identification Service.</AbstractText>A total of 252 patients underwent CRT during the study period. Seventy five percent were in New York Heart Associatin (NYHA) functional class III and mean ejection fraction was 29 ± 10%. Complete left bundle branch block was present in 55% and 20% had permanent atrial fibrillation (AF). Mean survival was 86% at 1 year and 82% of patients in NYHA class III-IV improved at least one functional class. Survival was poorer in patients with ischemic etiology (hazard ratio (HR) 1.48), functional class IV (HR 2.2), right bundle branch block (RBBB) (HR 3.1) and AF (HR 3.4). No survival differences were observed between patients with and without an implanted cardiodefibrillator.</AbstractText>This series show good clinical outcomes, comparable to those reported in randomized trials. Predictors of worse survival included an ischemic etiology, functional class IV, RBBB and AF. Patients with a defibrillator had no better survival, which could be relevant in countries with limited health care resources.</AbstractText> |
12,234 | Tachycardia mediated cardiomyopathy: pathophysiology, mechanisms, clinical features and management. | Tachycardia mediated cardiomyopathy (TMC) is a reversible form of dilated cardiomyopathy that can occur with most supraventricular and ventricular arrhythmias. Despite the plethora of literature describing this entity in animal models, as well as humans, it remains poorly understood. Over the last decade, new etiologies of TMC, such as frequent premature ventricular complexes in normal hearts, have been identified. Recent advances in catheter-based ablation therapies, particularly for atrial fibrillation and ventricular arrhythmias, have added a new dimension to the treatment of this condition. This review describes the pathophysiology, proposed mechanisms, clinical features and management in various arrhythmic conditions. |
12,235 | Hypertrophic cardiomyopathy with intermittent free mitral regurgitation-a surgical dilemma. | We describe the case of a 52-year-old woman presenting with non-ST elevation myocardial infarction, atrial fibrillation, and a new diagnosis of hypertrophic cardiomyopathy. Transesophageal echocardiography following hemodynamic deterioration revealed completely restricted mitral leaflet motion with free mitral regurgitation, and severe left ventricular outflow tract (LVOT) obstruction. Surgical intervention was considered; however, repeat imaging following a period of clinical stability revealed resolution of the findings suggesting a transient ischemic etiology. The case is supported by clinical and echocardiographic images with movie clips, and a discussion of the likely pathology in the context of the underlying condition. |
12,236 | Safety and feasibility of concomitant surgical ablation of atrial fibrillation in patients with severely reduced left ventricular ejection fraction. | Concomitant surgical ablation of atrial fibrillation (AF) is a safe and feasible procedure. However, many surgeons are reluctant to perform it in patients with heart failure. We investigated the safety and efficacy of AF ablation in patients with a severely reduced left ventricular ejection fraction (LVEF <35%).</AbstractText>Between July 2003 and August 2011, 59 patients with severely reduced LVEF underwent concomitant surgical AF ablation, by either left atrial (LA) lesion set or bilateral pulmonary vein isolation in patients with paroxysmal AF, and biatrial lesion set in patients with persistent AF. Follow-up echocardiography (ECG) was conducted after 12 months; rhythm monitoring was accomplished by either 24-h Holter echocardiography or event recorder monitoring.</AbstractText>The patients' mean age was 68 ± 9 years (male patients, 71%). Paroxysmal AF was present in 24 (41%) and persistent AF in 35 (59%) patients. No ablation-related adverse events occurred. The one-year survival rate was 95% without differences in patients with and without restoration of sinus rhythm (SR). The overall rate of SR was 54% after 1 year, showing a superior result in patients with preoperative paroxysmal AF compared with those with preoperative persistent AF (70 vs 41%, P < 0.001). LVEF improved from 29 ± 8% preoperatively to 39 ± 7% after 12 months of follow-up. The improvement in LVEF was significantly higher in patients with restored SR than in those with AF (16 vs 5%; P < 0.001). Only patients with restoration of SR showed a statistically significant reduction in New York Heart Association functional class at the 12-month follow-up (P = 0.0013).</AbstractText>Surgical AF ablation was safe and feasible in patients with severely reduced LVEF. The restoration of SR led to a significantly higher improvement in LVEF and alleviation of clinical heart failure symptoms, not observed if AF persisted postoperatively.</AbstractText>© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.</CopyrightInformation> |
12,237 | [Device therapy after acute coronary syndrome]. | Acute coronary syndromes are seldom accompanied by high degree AV blocks. Implantation of a permanent pacemaker is rarely necessary.There is a high incidence of ventricular tachyarrhythmias during the acute phase of myocardial infarctions. Sustained VT or VF beyond 48 hours of the infarction indicate the need for an implantable cardioverter-defibrillator. If left ventricular ejecion fraction remains ≤35 % for >40 days an ICD might be indicated for primary prophylaxis.If early after infarction a device implantation becomes necessary, biventricular stimulation should be used if ventricular pacing is necessary or LBBB with markedly increased QRS-duration is present. |
12,238 | A rare loss-of-function SCN5A variant is associated with lidocaine-induced ventricular fibrillation. | The human genome contains over 4 million variant sites, as compared with the reference genome, including rare sequence variants, which have the potential to exert large phenotypic effects, such as susceptibility to drug toxicity. We report identification and functional characterization of a rare non-synonymous (p.A1427S) variant in the SCN5A gene that was associated with incessant and lethal ventricular tachycardia and fibrillation after administration of lidocaine to a patient with acute myocardial infarction. The variant, located in a highly conserved domain distinct from the predicted lidocaine-binding site, decreased peak current density of the sodium channel. With the increasing availability of the whole exome and whole genome sequencing data, it would be possible to identify and characterize rare variants in SCN5A that might predispose to lethal ventricular arrhythmias. |
12,239 | Reduced aerobic capacity causes leaky ryanodine receptors that trigger arrhythmia in a rat strain artificially selected and bred for low aerobic running capacity. | Rats selectively bred for inborn low capacity of running (LCR) display a series of poor health indices, whereas rats selected for high capacity of running (HCR) display a healthy profile. We hypothesized that selection of low aerobic capacity over generations leads to a phenotype with increased diastolic Ca(2+) leak that trigger arrhythmia.</AbstractText>We used rats selected for HCR (N = 10) or LCR (N = 10) to determine the effect of inborn aerobic capacity on Ca(2+) leak and susceptibility of ventricular arrhythmia. We studied isolated Fura-2/AM-loaded cardiomyocytes to detect Ca(2+) handling and function on an inverted epifluorescence microscope. To determine arrhythmogenicity, we did a final experiment with electrical burst pacing in Langendorff-perfused hearts.</AbstractText>Ca(2+) handling was impaired by reduced Ca(2+) amplitude, prolonged time to 50% Ca(2+) decay and reduced sarcoplasmic reticulum (SR) Ca(2+) content. Impaired Ca(2+) removal was influenced by reduced SR Ca(2+) ATP-ase 2a (SERCA2a) function and increased sodium/Ca(2+) exchanger (NCX) in LCR rats. Diastolic Ca(2) leak was 87% higher in LCR rats. The leak was reduced by CaMKII inhibition. Expression levels of phosphorylated threonine 286 CaMKII levels and increased RyR2 phosphorylation at the serine 2814 site mechanistically support our findings of increased leak in LCR. LCR rats had significantly higher incidence of ventricular fibrillation.</AbstractText>Selection of inborn low aerobic capacity over generations leads to a phenotype with increased risk of ventricular fibrillation. Increased phosphorylation of CaMKII at serine 2814 at the cardiac ryanodine receptor appears as an important mechanism of impaired Ca(2+) handling and diastolic Ca(2+) leak that results in increased susceptibility to ventricular fibrillation.</AbstractText>© 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.</CopyrightInformation> |
12,240 | Impact of the presence and amount of myocardial fibrosis by cardiac magnetic resonance on arrhythmic outcome and sudden cardiac death in nonischemic dilated cardiomyopathy. | Current risk stratification for sudden cardiac death (SCD) in nonischemic dilated cardiomyopathy (NIDC) relies on left ventricular (LV) dysfunction, a poor marker of ventricular electrical instability. Contrast-enhanced cardiac magnetic resonance has the ability to accurately identify and quantify ventricular myocardial fibrosis (late gadolinium enhancement [LGE]).</AbstractText>To evaluate the impact of the presence and amount of myocardial fibrosis on arrhythmogenic risk prediction in NIDC.</AbstractText>One hundred thirty-seven consecutive patients with angiographically proven NIDC were enrolled for this study. All patients were followed up for a combined arrhythmic end point including sustained ventricular tachycardia (VT), appropriate implantable cardioverter-defibrillator (ICD) intervention, ventricular fibrillation (VF), and SCD.</AbstractText>LV-LGE was identified in 76 (55.5%) patients. During a median follow-up of 3 years, the combined arrhythmic end point occurred in 22 (16.1%) patients: 8 (5.8%) sustained VT, 9 (6.6%) appropriate ICD intervention, either against VF (n = 5; 3.6%) or VT (n = 4; 2.9%), 3 (2.2%) aborted SCD, and 2 (1.5%) died suddenly. Kaplan-Meier analysis revealed a significant correlation between the LV-LGE presence (not the amount and distribution) and malignant arrhythmic events (P < .001). In univariate Cox regression analysis, LV-LGE (hazard ratio [HR] 4.17; 95% confidence interval [CI] 1.56-11.2; P = .005) and left bundle branch block (HR 2.43; 95% CI 1.01-5.41; P = .048) were found to be associated with arrhythmias. In multivariable analysis, the presence of LGE was the only independent predictor of arrhythmias (HR 3.8; 95% CI 1.3-10.4; P = .01).</AbstractText>LV-LGE is a powerful and independent predictor of malignant arrhythmic prognosis, while its amount and distribution do not provide additional prognostic value. Contrast-enhanced cardiac magnetic resonance may contribute to identify candidates for ICD therapy not fulfilling the current criteria based on left ventricular ejection fraction.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,241 | Atrial flutter with 1:1 conduction in undiagnosed Wolff-Parkinson-White syndrome. | Atrial flutter with 1:1 atrioventricular conduction via an accessory pathway is an uncommon presentation of Wolff-Parkinson-White syndrome not previously reported in the emergency medicine literature. Wolff-Parkinson-White syndrome, a form of ventricular preexcitation sometimes initially seen and diagnosed in the emergency department (ED), can present with varied tachydysrhythmias for which certain treatments are contraindicated. For instance, atrial fibrillation with preexcited conduction needs specific consideration of medication choice to avoid potential degeneration into ventricular fibrillation.</AbstractText>We describe an adult female presenting with a very rapid, regular wide complex tachycardia successfully cardioverted in the ED followed by a normal electrocardiogram (ECG). Electrophysiology study confirmed atrial flutter with 1:1 conduction and revealed an accessory pathway consistent with Wolff-Parkinson-White syndrome, despite lack of ECG findings of preexcitation during sinus rhythm. Why should an emergency physician be aware of this? Ventricular tachycardia must be the first consideration in patients with regular wide complex tachycardia. However, clinicians should consider atrial flutter with 1:1 conduction related to an accessory pathway when treating patients with the triad of very rapid rate (>250 beats/min), wide QRS complex, and regular rhythm, especially when considering pharmacologic treatment. Emergency physicians also should be aware of electrocardiographically concealed accessory pathways, and that lack of delta waves does not rule out preexcitation syndromes such as Wolff-Parkinson-White syndrome.</AbstractText>Copyright © 2014 Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,242 | Comparison of the safety and feasibility of arrhythmia ablation using the Amigo Robotic Remote Catheter System versus manual ablation. | The aim of this study is to evaluate the safety and feasibility of using the Amigo Remote Catheter System (RCS) in arrhythmia ablation procedures. Because Amigo allows the physician to operate all catheter function outside of the radiation field, operator exposure time was also evaluated. This is a nonrandomized, prospective clinical trial conducted at 1 site (identifier: NCT01834872). The study prospectively enrolled 50 consecutive patients (mean age 59 ± 15 years, 72% men) with any type of arrhythmia (23 atrial fibrillation ablation, 12 common atrial flutters, 10 patients with other supraventricular tachycardia, 4 ventricular tachycardia, and 1 patient with palpitations with no arrhythmia induced) referred for catheter ablation, in which we used RCS. Fifty matched ablation procedures (mean age 57 ± 14 years, 70% men) performed during the same time period, without RCS, were enrolled into the control group. Acute ablation success was 96% with RCS and 98% in the manual group. In only 2 cases, the physician switched to manual ablation (1 ventricular tachycardia and 1 accessory pathway) to complete the procedure. There were no complications related to the use of RCS. No differences were observed in total procedure time, total fluoroscopy time, or total radiofrequency delivery compared with the manual group. In procedures performed with RCS, the operator's fluoroscopy exposure time was reduced by 68 ± 16%. In conclusion, arrhythmia ablation with RCS is safe and feasible. Furthermore, it significantly reduces operator's exposure to radiation. |
12,243 | Usefulness of right ventricular dysfunction to predict new-onset atrial fibrillation following coronary artery bypass grafting. | Postoperative atrial fibrillation (AF) is a serious yet common complication after coronary artery bypass grafting (CABG) surgery. Risk factors for postoperative AF have been identified, including echocardiographic parameters, and these are relied on to implement preventative strategies that reduce the incidence of AF. There has yet to be a study examining the impact of echocardiographic right-sided cardiac parameters on the prediction of postoperative AF. Thus, a panel of right-sided cardiac parameters was measured in a cohort of patients undergoing isolated CABG surgery, excluding those who did not have echocardiographic assessment within 30 days before surgery and those with any history of AF. The primary outcome was postoperative AF defined as any episode of AF requiring treatment during the index hospitalization. Postoperative AF occurred in 197 of 768 patients (25.6%); these were older and more likely to have hypertension and chronic kidney disease. After adjustment for clinical and echocardiographic variables, left atrial volume index ≥34 ml/m(2) (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.36 to 2.87), abnormal right ventricular myocardial performance index (OR 1.50, 95% CI 1.01 to 2.24), and advancing age (OR 1.05, 95% CI 1.03 to 1.07) were found to be independent predictors of postoperative AF. In conclusion, right ventricular myocardial performance index is a novel predictor of postoperative AF in patients undergoing isolated CABG surgery and appears to be additive to established risk factors such as age and left atrial volume. |
12,244 | Absolute survival after cardiac resynchronization therapy according to baseline QRS duration: a multinational 10-year experience: data from the Multicenter International CRT Study. | In the major trials of cardiac resynchronization therapy (CRT), the survival benefit of the therapy, relative to control subjects, increases with QRS duration. In the non-CRT heart failure population, however, a wide QRS duration is associated with a shorter survival. Relative survival benefit from a therapy, however, is not synonymous with a longer absolute survival. We sought to determine whether baseline QRS duration relates to the absolute survival after CRT.</AbstractText>In this prospective, longitudinal, observational study, 3,319 consecutive patients undergoing CRT (QRS 120-149 ms 26%, QRS 150-199 ms 58%, and QRS ≥200 ms 16%) were assessed in relation to mortality over 10 years. Overall mortality rates (per 100 patient-years) were 9.2%, 9.3%, and 13.3% in the 3 groups, respectively (all P < .001). Cardiac mortality rates were 6.2, 6.0, and 9.9 per 100 patient-years, respectively (all P < .001). Compared with the QRS 120-149 ms group, cardiac mortality was highest in the QRS ≥200 ms group (hazard ratio [HR] 1.72 [95% CI 1.35-2.19], P < .001), independent of age, gender, New York Heart Association class, presence of atrial fibrillation, heart failure etiology, and left ventricular ejection fraction. Median survival after CRT was longest in patients with a width of QRS 120-149 ms and shortest in patients with a QRS ≥200 ms (P < .001). In multivariable analyses, a QRS ≥200 ms emerged as a powerful independent predictor of both overall (HR 1.44 [95% CI 1.07-1.94], P = .017) and cardiac mortality (HR 1.59 [95% CI 1.14-2.24], P = .007).</AbstractText>At long-term follow-up, absolute overall and cardiac survival after CRT is similar in patients with a preimplant QRS duration of 120 to 149 ms and 150 to 199 ms but markedly shorter in patients with a QRS ≥200 ms.</AbstractText>© 2014.</CopyrightInformation> |
12,245 | Ablation of idiopathic ventricular fibrillation targeting short coupled ventricular premature contractions originating from a right ventricular papillary muscle. | We describe a 38-year-old male who experienced several episodes of syncope after having ventricular fibrillation. The electrocardiographic monitoring after his hospitalization revealed repetitive polymorphic ventricular tachycardias. All polymorphic ventricular tachycardias were consistently initiated by a short-coupled monomorphic ventricular premature contraction (VPC). This VPC was suggested to originate from the inferoposterior region of the right ventricle (RV). Radiofrequency catheter ablation targeting the VPC was successfully performed, and the CARTO merge system (Biosense Webster Inc., Diamond Bar, CA, USA) revealed that the culprit region was the root of the posterior papillary muscle of the RV. A subsequent follow-up of 15 months has been uneventful. <<b>Learning objective:</b> This is a case report of idiopathic ventricular fibrillation (IVF) triggered by a ventricular premature contraction (VPC) from the posterior papillary muscle of the right ventricle. We can learn about the relationship between the anatomical structure and the possible mechanisms of the short-coupled variant of Torsade de Pointes.>. |
12,246 | The effects of the rate of postresuscitation rewarming following hypothermia on outcomes of cardiopulmonary resuscitation in a rat model. | To investigate the optimal rewarming rate following therapeutic hypothermia in a rate model of cardiopulmonary resuscitation. Both clinical and laboratory studies have demonstrated that mild therapeutic hypothermia following cardiopulmonary resuscitation improves myocardial and neurologic outcomes of cardiac arrest. However, the optimal rewarming strategy following therapeutic hypothermia remains to be explored.</AbstractText>Prospective randomized controlled experimental study.</AbstractText>University-affiliated research institution.</AbstractText>Twenty-three healthy male Sprague-Dawley rats.</AbstractText>Four groups of Sprague-Dawley rats were randomized: 1) normothermia group (control), 2) rewarming rate at 2°C/hr, 3) rewarming rate at 1°C/hr, and 4) rewarming rate at 0.5°C/hr. Ventricular fibrillation was induced and untreated for 8 minutes, and defibrillation was attempted after 8 minutes of cardiopulmonary resuscitation. For the 2, 1, and 0.5°C/hr groups, rapid cooling was started at the beginning of cardiopulmonary resuscitation. On reaching the target cooling temperature of 33°C ± 0.2°C, the temperature was maintained with the aid of a cooling blanket until 4 hours after resuscitation. Rewarming was then initiated at the rate of 2.0, 1.0, or 0.5°C/hr, respectively, until the body temperature reached 37°C ±0.2°C. Blood samples were drawn at baseline and postresuscitation of 4, 6, 8, 10, and 12 hours for the measurements of blood gas and serum biomarkers.</AbstractText>Blood temperature significantly decreased in the hypothermic groups from cardiopulmonary resuscitation to postresuscitation 4 hours. Significantly better cardiac output, ejection fraction, myocardial performance index, reduced neurologic deficit scores, and longer duration of survival were observed in the 1 and 0.5°C/hr groups. The increased serum concentration of troponin I, interleukin-6, and tumor necrosis factor-α was partly attenuated in the 1 and 0.5°C/hr groups when compared with the control and 2°C/hr groups.</AbstractText>This study demonstrated that the severity of myocardial, cerebral injuries, and inflammatory reaction after cardiopulmonary resuscitation was reduced when mild therapeutic hypothermia was applied. A rewarming rate at 0.5-1°C/hr did not alter the beneficial effects of therapeutic hypothermia. However, a rapid rewarming rate at 2°C/hr abolished the beneficial effects of hypothermia.</AbstractText> |
12,247 | Ischaemic hepatitis precipitated by recurrent episodes of atrial fibrillation. | We report a case of ischaemic hepatitis associated with recurrent fast atrial fibrillation (AF) episodes in a 59-year-old male who presented with shortness of breath, nausea and vomiting. The patient had a history of ischaemic cardiomyopathy. An emergency electrocardiogram showed fast AF with a ventricular rate of 190 min(-1). The aspartate aminotransferase (AST) level was 2222Ul(-1), alanine aminotransferase (ALT) was 1255Ul(-1), lactate dehydrogenase (LDH) was 1842Ul(-1) and serum creatinine was 150 μmoll(-1). An ultrasound of the abdomen showed an enlarged liver with hypoechoic lesions. The patient received digoxin. In the next few days, while liver enzymes and serum creatinine started to return to normal levels, the patient had two attacks of fast AF, each associated with elevated liver enzymes and a concomitant rise in serum creatinine. The patient was transferred to the intensive care unit to improve control of his AF, after which his liver enzymes and renal function gradually returned to normal. |
12,248 | Non-fluoroscopic catheter visualization using MediGuide™ technology: experience from the first 600 procedures. | A novel cardiovascular navigation system known as MediGuide™ (MG) which allows non-fluoroscopic catheter tracking over a background of pre-recorded cine loops was recently introduced. This system allows significant reduction of fluoroscopy exposure which is one of the potentially harmful aspects of today's electrophysiological procedures such as ablations or device implantations. We provide a summary of recently published studies related to this new technological platform and describe our experience from the first 600 MG procedures at our institution.After reviewing the currently available publications in the field of MG-supported EP procedures, we describe the workflows for (1) ablation of supraventricular tachycardia (SVT), atrial fibrillation (AF), and ventricular tachycardia using MG-enabled diagnostic and ablation catheters, as well as (2) implant of cardiac resynchronization therapy (CRT) devices using sensor-equipped delivery tools including sheaths, sub-selectors, and guidewires.As shown in several studies [5-9], MG procedures resulted in similar efficacy as conventional cases but with a significant reduction in fluoroscopy time and dose. In particular, for SVT ablations, the median fluoroscopy time using the MG technology was 0.5 ± 1.4 min compared to 10.2 ± 9.6 min in conventional fluoroscopic settings. Similar reductions were demonstrated for AF ablation procedures from 25 min in conventional settings with electroanatomical mapping systems and live x-ray to 4.6 min with the addition of the MG technology. Recently, it was demonstrated that the application of MG for CRT device implants could successfully result in a median fluoroscopy time of 2.6 min for LV lead deployment.In summary, the first measurable clinical impact of the MG technology on a daily clinical routine is the reduction of fluoroscopy time and radiation exposure for various EP indications. These beneficial effects were achieved without negative consequences on procedural efficacy, complications, or time in more than 600 EP procedures. |
12,249 | [A man in his eighties with recurrent syncope]. | Syncope is usually a benign event that affects up to 50% of people over a lifetime, needing no extensive examination. The challenge is to diagnose the few with underlying life-threatening disease in need of immediate medical attention. Guidelines are clear, but unfortunately, clinical practice does not always follow recommendations, as illustrated by this case report.</AbstractText>A diabetic, hypertensive male in his eighties had a myocardial infarction in his medical history. He presented to his GP with recurrent syncopal episodes that had occurred while erect and in motion. Physical examination was found to be normal for his age, and he was referred to a cardiologist and seen three months later. An ECG showed sinus rhythm and a previous inferior wall myocardial infarction. A 24-hour ECG recorder was fitted, and a consultation was scheduled for the next day. At home the patient died. The ECG recording revealed sinus rhythm with increasing depression of the ST segment, followed by rapidly conducted atrial fibrillation, and then rapid ventricular tachycardia followed by terminal ventricular fibrillation.</AbstractText>A patient with a history where there is suspicion of cardiac syncope should be immediately and intensively examined when presenting to the healthcare services.</AbstractText> |
12,250 | Feasibility and efficacy of mitral valve repair for degenerative mitral regurgitation in the elderly. | The number of elderly patients who require surgical treatment for mitral regurgitation (MR) is increasing. However, the feasibility and efficacy of mitral valve repair in elderly patients are unclear.</AbstractText>We retrospectively reviewed 55 patients, aged ≥75 years, who underwent mitral valve repair for degenerative MR between 1991 and 2011. All patients were followed up for 4.7 ± 3.4 years.</AbstractText>The patients aged ≥75 years were more symptomatic and had a higher incidence of persistent atrial fibrillation and pulmonary hypertension than those aged &lt;75 years. Thirty-day and in-hospital mortality was 1.8% and 7.3%, respectively, and the 5-year survival rate was 81.6% ± 5.8%. The leading cause of late death was stroke, which primarily occurred in patients with postoperative atrial fibrillation. Except for a single failure of repair due to technical reasons, there was no recurrence of severe MR or reoperation on the mitral valve. In the late follow-up period, the mean left ventricular diastolic diameter significantly decreased and the mean left ventricular ejection fraction was approximately 60%. Most patients had mild symptoms at follow-up.</AbstractText>Mitral valve repair can provide satisfactory early as well as long-term outcomes and can preserve left ventricular function even in the elderly.</AbstractText> |
12,251 | Cellular mechanism underlying hypothermia-induced ventricular tachycardia/ventricular fibrillation in the setting of early repolarization and the protective effect of quinidine, cilostazol, and milrinone. | Hypothermia has been reported to induce ventricular tachycardia and fibrillation (VT/VF) in patients with early repolarization (ER) pattern. This study examines the cellular mechanisms underlying VT/VF associated with hypothermia in an experimental model of ER syndrome and examines the effectiveness of quinidine, cilostazol, and milrinone to prevent hypothermia-induced arrhythmias.</AbstractText>Transmembrane action potentials were simultaneously recorded from 2 epicardial and 1 endocardial site of coronary-perfused canine left ventricular wedge preparations, together with a pseudo-ECG. A combination of NS5806 (3-10 μmol/L) and verapamil (1 μmol/L) was used to pharmacologically model the genetic mutations responsible for ER syndrome. Acetylcholine (3 μmol/L) was used to simulate increased parasympathetic tone, which is known to promote ER. In controls, lowering the temperature of the coronary perfusate to induce mild hypothermia (32°C-34°C) resulted in increased J-wave area on the ECG and accentuated epicardial action potential notch but no arrhythmic activity. In the setting of ER, hypothermia caused further accentuation of the epicardial action potential notch, leading to loss of the action potential dome at some sites but not others, thus creating the substrate for development of phase 2 reentry and VT/VF. Addition of the transient outward current antagonist quinidine (5 μmol/L) or the phosphodiesterase III inhibitors cilostazol (10 μmol/L) or milrinone (5 μmol/L) diminished the ER manifestations and prevented the hypothermia-induced phase 2 reentry and VT/VF.</AbstractText>Hypothermia leads to VT/VF in the setting of ER by exaggerating repolarization abnormalities, leading to development of phase 2 reentry. Quinidine, cilostazol, and milrinone suppress the hypothermia-induced VT/VF by reversing the repolarization abnormalities.</AbstractText> |
12,252 | A study of early afterdepolarizations in a model for human ventricular tissue. | Sudden cardiac death is often caused by cardiac arrhythmias. Recently, special attention has been given to a certain arrhythmogenic condition, the long-QT syndrome, which occurs as a result of genetic mutations or drug toxicity. The underlying mechanisms of arrhythmias, caused by the long-QT syndrome, are not fully understood. However, arrhythmias are often connected to special excitations of cardiac cells, called early afterdepolarizations (EADs), which are depolarizations during the repolarizing phase of the action potential. So far, EADs have been studied mainly in isolated cardiac cells. However, the question on how EADs at the single-cell level can result in fibrillation at the tissue level, especially in human cell models, has not been widely studied yet. In this paper, we study wave patterns that result from single-cell EAD dynamics in a mathematical model for human ventricular cardiac tissue. We induce EADs by modeling experimental conditions which have been shown to evoke EADs at a single-cell level: by an increase of L-type Ca currents and a decrease of the delayed rectifier potassium currents. We show that, at the tissue level and depending on these parameters, three types of abnormal wave patterns emerge. We classify them into two types of spiral fibrillation and one type of oscillatory dynamics. Moreover, we find that the emergent wave patterns can be driven by calcium or sodium currents and we find phase waves in the oscillatory excitation regime. From our simulations we predict that arrhythmias caused by EADs can occur during normal wave propagation and do not require tissue heterogeneities. Experimental verification of our results is possible for experiments at the cell-culture level, where EADs can be induced by an increase of the L-type calcium conductance and by the application of I[Formula: see text] blockers, and the properties of the emergent patterns can be studied by optical mapping of the voltage and calcium. |
12,253 | Regional ion channel gene expression heterogeneity and ventricular fibrillation dynamics in human hearts. | Structural differences between ventricular regions may not be the sole determinant of local ventricular fibrillation (VF) dynamics and molecular remodeling may play a role.</AbstractText>To define regional ion channel expression in myopathic hearts compared to normal hearts, and correlate expression to regional VF dynamics.</AbstractText>High throughput real-time RT-PCR was used to quantify the expression patterns of 84 ion-channel, calcium cycling, connexin and related gene transcripts from sites in the LV, septum, and RV in 8 patients undergoing transplantation. An additional eight non-diseased donor human hearts served as controls. To relate local ion channel expression change to VF dynamics localized VF mapping was performed on the explanted myopathic hearts right adjacent to sampled regions. Compared to non-diseased ventricles, significant differences (p<0.05) were identified in the expression of 23 genes in the myopathic LV and 32 genes in the myopathic RV. Within the myopathic hearts significant regional (LV vs septum vs RV) expression differences were observed for 13 subunits: Nav1.1, Cx43, Ca3.1, Cavα2δ2, Cavβ2, HCN2, Na/K ATPase-1, CASQ1, CASQ2, RYR2, Kir2.3, Kir3.4, SUR2 (p<0.05). In a subset of genes we demonstrated differences in protein expression between control and myopathic hearts, which were concordant with the mRNA expression profiles for these genes. Variability in the expression of Cx43, hERG, Na(+)/K(+) ATPase ß1 and Kir2.1 correlated to variability in local VF dynamics (p<0.001). To better understand the contribution of multiple ion channel changes on VF frequency, simulations of a human myocyte model were conducted. These simulations demonstrated the complex nature by which VF dynamics are regulated when multi-channel changes are occurring simultaneously, compared to known linear relationships.</AbstractText>Ion channel expression profile in myopathic human hearts is significantly altered compared to normal hearts. Multi-channel ion changes influence VF dynamic in a complex manner not predicted by known single channel linear relationships.</AbstractText> |
12,254 | Periodic limb movements during sleep and cardiac arrhythmia in older men (MrOS sleep). | To determine if periodic limb movements during sleep (PLMS) are associated with nocturnal cardiac arrhythmia.</AbstractText>2,793 community-dwelling older men underwent polysomnography with measurement of limb movements and EKG. Logistic regression assessed association of periodic limb movement index and periodic limb movement arousal index with arrhythmia including atrial fibrillation and non-sustained ventricular tachycardia detected by polysomnography. Models were adjusted for age, race, cardiovascular risk factors, and clinic site. Secondary analyses were subset to men without calcium channel/β-adrenergic medication usage, and stratified by congestive heart failure or myocardial infarction history.</AbstractText>In the overall cohort, periodic limb movement index, and periodic limb movement arousal index were not associated with ventricular or atrial arrhythmia after considering potential confounders. In men not taking calcium channel/β-blocking medication, increased adjusted odds of non-sustained ventricular tachycardia were observed for periodic limb movement index (OR = 1.30 per SD increase; 95% CI 1.00, 1.68) and periodic limb movement arousal index (OR = 1.29 per SD increase; 95% CI 1.03, 1.62). In men with CHF or MI, there was a suggested association of atrial fibrillation with periodic limb movement index (OR = 1.29, 95% CI 0.96, 1.73 per SD increase; p = 0.09) or periodic limb movement arousal index (OR = 1.21, 95% CI 0.94, 1.57 per SD increase; p = 0.14), although results were not statistically significant.</AbstractText>There is not an association between PLMS and cardiac arrhythmia in all older men but in subsets of men, particularly those with structural heart disease and not on calcium channel or β-adrenergic medication, cardiac arrhythmia does associate with PLMS.</AbstractText> |
12,255 | Seizure secondary to cardiac arrythmias. | The relationship between seizure activity and arrhythmias is not well established. Sinus tachycardia is commonly seen post seizure. Bradyarrythmias leading to seizure activity is rarely reported in the literature thus far.</AbstractText>A 62-year-old lady presented with nocturnal seizures and was subsequently started on oral anti-convulsant with no relief of her symptoms. Further investigations led to outpatient ambulatory ECGs which showed marked sinus bradycardia prior to seizure activity and post seizure atrial fibrillation with fast ventricular rate. The patient was commenced on oral anticoagulant and beta blocker for ventricular rate control in view of atrial fibrillation. A backup dual chamber permanent pacemaker was implanted to treat the bradycardia. The patient became seizure free since the implantation of permanent pacemaker.</AbstractText>This case stresses the importance of investigating and treating cardiac arrhythmias underlying seizure activity.</AbstractText> |
12,256 | Assessment of atrial electromechanical delay using tissue Doppler echocardiography in children with asthma. | Right ventricular (RV) dysfunction, pulmonary hypertension, atrial enlargement, and cor pulmonale may be associated with asthma. These pathological conditions may disturb the electrophysiological properties of the right atrium. This study investigated the atrial electromechanical delay and P-wave dispersion (PWD) in patients with asthma. Thirty-four children aged 8-16 years who were being followed up for asthma constituted the patient group, and 34 age- and body mass index-matched patients constituted the control group. Both groups underwent RV tissue Doppler measurements, intra-right atrial conduction time (IRCT-echo) determination, intra-left atrial conduction time (ILCT-echo) determination, inter-atrial conduction time (IACT-echo) determination, and PWD measurement. The IRCT-echo (14.38 ± 5.46 and 8.20 ± 3.90 ms; p < 0.001) and IACT-echo (28.97 ± 6.58 and 22.79 ± 6.28 ms; p < 0.001) were higher in patients with asthma than in the control group. The PWD (44.58 ± 17.51 and 38.11 ± 13.50 ms; p = 0.09), maximum P-wave duration (87.94 ± 18.20 and 82.44 ± 16.36 ms, p = 0.19), minimum P-wave duration (43.58 ± 9.95 and 44.79 ± 9.13 ms; p = 0.60), and ILCT-echo (15.88 ± 5.40 and 14.58 ± 4.94 ms; p = 0.30) were similar between the two groups. The IRCT-echo was positively correlated with the isovolumetric relaxation time of the lateral tricuspid annulus (r = 0.60; p < 0.001) and with the myocardial performance index of the lateral tricuspid annulus (r = 0.59; p < 0.001) in patients with asthma. The IRCT-echo and IACT-echo were higher in patients with asthma than in the control group. The deterioration of the electrophysiological properties of the right atrium may result in a risk of atrial fibrillation in patients with asthma. |
12,257 | Nav1.8 channels in ganglionated plexi modulate atrial fibrillation inducibility. | Emerging evidences indicate that SCN10A/NaV1.8 is associated with cardiac conduction and atrial fibrillation, but the exact role of NaV1.8 in cardiac electrophysiology remains poorly understood. The present study was designed to investigate the effects of blocking NaV1.8 channels in cardiac ganglionated plexi (GP) on modulating cardiac conduction and atrial fibrillation inducibility in the canine model.</AbstractText>Thirteen mongrel dogs were randomly enrolled. Right cervical vagus nerve stimulation (VNS) was applied to determine its effects on the sinus rate, ventricular rate during atrial fibrillation, PR interval, atrial effective refractory period, and the cumulative window of vulnerability. The NaV1.8 blocker A-803467 (1 μmol/0.5 mL per GP, n = 7) or 5% DMSO/95% polyethylene glycol (0.5 mL per GP, n = 6, control) was injected into the anterior right GP and the inferior right GP. The effects of VNS on the sinus rate, ventricular rate, PR interval, atrial effective refractory period, and the cumulative window of vulnerability were significantly eliminated at 10, 35, and 90 min after A-803467 injection. In separate experiments (n = 8), A-803467 blunted the slowing of sinus rate with increasing stimulation voltage of the anterior right GP at 10 min after local injection.</AbstractText>Blockade of NaV1.8 channels suppresses the effects of VNS on cardiac conduction and atrial fibrillation inducibility, most likely by inhibiting the neural activity of the cardiac GP.</AbstractText>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation> |
12,258 | Elevated plasma free fatty acids are associated with sudden death: a prospective community-based evaluation at the time of cardiac arrest. | In cohort studies, elevated levels of plasma nonesterified free fatty acids (NEFAs) have been associated with increased risk of sudden cardiac death (SCD) in men, but blood samples were drawn several years before SCD.</AbstractText>To confirm this relationship by evaluating levels of plasma NEFAs at the time of the SCD event in a group of both men and women.</AbstractText>From the ongoing Oregon Sudden Unexpected Death Study, we compared levels of plasma NEFAs in 149 SCD cases presenting with ventricular fibrillation (mean age 64 ± 12 years; 73% men) and 149 age- and sex-matched controls with coronary artery disease. Plasma was processed from blood drawn at the time of arrest (cases) and at a routine visit (controls). The levels of plasma NEFAs were compared after categorizing into quartiles on the basis of control values. Conditional logistic regression was used to predict adjusted odds ratio for SCD associated with plasma NEFA levels per increased quartile.</AbstractText>The plasma NEFA levels were significantly higher in SCD cases than in controls (median 0.39 mmol/L [interquartile range 0.28-0.60 mmol/L] vs 0.32 mmol/L [interquartile range 0.20-0.49 mmol/L]; P = .002). There were no significant differences in body mass index, smoking, and diabetes. The odds ratio for SCD was 1.42 (95% confidence interval 1.14-1.78) per quartile increase in the plasma NEFA level (P = .002). Individuals with plasma NEFA levels above the prespecified cutoff point of 0.32 mmol/L were at increased risk of SCD (odds ratio 2.00; 95% confidence interval 1.20-3.34; P = .008).</AbstractText>These findings strengthen the role of plasma NEFA as a potential biomarker for the assessment of SCD risk.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,259 | Active or passive pulmonary vein in atrial fibrillation: is pulmonary vein isolation always essential? | The role of pulmonary veins (PVs) in persistent atrial fibrillation (AF) perpetuation appears less important than in paroxysmal AF. Electrogram-based substrate ablation is not widely performed as a stand-alone strategy.</AbstractText>To evaluate PV activity in AF perpetuation and efficacy of our patient-tailored ablation strategy (electrogram-based substrate ablation with or without pulmonary vein isolation [PVI]).</AbstractText>One hundred twenty-one patients with paroxysmal (n = 19; 15.7%), persistent (n = 77; 63.6%), or long-standing persistent (n = 25; 20.7%) AF underwent electrogram-based substrate ablation with AF termination end point: sinus rhythm or atrial tachycardia conversion. Before ablation, we classified PVs as "passive" if silent PV or if PV cycle length is greater than left atrial appendage cycle length. No PVI was performed in such cases.</AbstractText>Passive PVs were observed in 52 of 121 patients (paroxysmal AF = 0%, persistent AF = 40%, and long-standing persistent AF = 76%; P < .0001]). Substrate ablation terminated AF in 95.6% (sinus rhythm conversion in 80.2%). Compared with patients with active PVs, patients with passive PVs had longer AF sustained duration (19.1 ± 29.7 months vs 4.9 ± 11.1 months; P < .0001), larger left atrial diameter (46.9 ± 7.3 mm vs 41.9 ± 6.0 mm; P = .0014), lower left ventricular ejection fraction (45.4% ± 13.5% vs 55.1% ± 9.4%; P < .0001), and more often structural heart disease (57% vs 33%; P = .02). After a follow-up of 20.39 ± 11.23 months (1.6 procedures per patient), 82% were arrhythmia free with this strategy.</AbstractText>PV activity during AF decreases with AF chronicity, left atrial dilatation, and left ventricular ejection fraction. Our patient-tailored ablation strategy without systematic PVI provides good results.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,260 | Managed ventricular pacing compared with conventional dual-chamber pacing for elective replacement in chronically paced patients: results of the Prefer for Elective Replacement Managed Ventricular Pacing randomized study. | Several studies have shown that unnecessary right ventricular pacing has detrimental effects.</AbstractText>To evaluate whether minimization of ventricular pacing as compared with standard dual-chamber pacing (DDD) improves clinical outcomes in patients referred for pacemaker or implantable cardioverter-defibrillator (ICD) replacement.</AbstractText>In an international single-blind, multicenter, randomized controlled trial, we compared DDD with managed ventricular pacing (MVP), a pacing mode developed to minimize ventricular pacing by promoting intrinsic atrioventricular conduction. We included patients referred for device replacement with >40% ventricular pacing, no cardiac resynchronization therapy upgrade indication, no permanent atrial fibrillation (AF), and no permanent complete atrioventricular block. Follow-up was for 2 years. The primary end point was cardiovascular hospitalization. The intention-to-treat analysis was performed by using Kaplan-Meier method and the log-rank test.</AbstractText>We randomized 605 patients (556 referred for pacemaker and 49 referred for ICD replacement; mean age 75 ± 11 years; 365 [60%] men, at 7.7 ± 3.3 years from first device implantation) to MVP (n = 299) or DDD (n = 306). We found no significant differences in the primary end point cardiovascular hospitalization (MVP: 16.3% vs DDD: 14.5%; P = .72) and the secondary end point persistent AF (MVP: 15.4% vs DDD: 11.2%; P = .08), permanent AF (MVP: 4.1% vs DDD: 3.1%; P = .44), and composite of death and cardiovascular hospitalization (MVP: 23.9% vs DDD: 20.2%; P = .48). MVP reduced right ventricular pacing (median 5% vs 86%; Wilcoxon, P < .0001) as compared with DDD.</AbstractText>In patients referred for pacemaker and ICD replacement with clinically well-tolerated long-term exposure to >40% ventricular pacing in the ventricle, a strategy to minimize ventricular pacing is not superior to standard DDD in reducing incidence of cardiovascular hospitalizations.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,261 | Absolute beat-to-beat variability and instability parameters of ECG intervals: biomarkers for predicting ischaemia-induced ventricular fibrillation. | Predicting lethal arrhythmia liability from beat-to-beat variability and instability (BVI) of the ECG intervals is a useful technique in drug assessment. Most investigators use only arrhythmia-free ECGs for this. Recently, it was shown that drug-induced torsades de pointes (TdP) liability can be predicted more accurately from BVI measured irrespective of rhythm, even during arrhythmias (absolute BVI). The present study tested the broader applicability of this assessment by examining whether absolute BVI parameters predict another potential lethal arrhythmia, ischaemia-induced ventricular fibrillation (VF).</AbstractText>Langendorff-perfused rat hearts were subjected to regional ischaemia for 15 min. Absolute BVI parameters were derived from ECG intervals measured in 40 consecutive ventricular complexes (irrespective of rhythm) immediately preceding VF onset and compared with time-matched values in hearts not expressing VF.</AbstractText>Increased frequency of non-sinus beats and 'R on T' arrhythmic beats, shortened mean RR and electrical diastolic intervals, and increased BVI of cycle length and repolarization predicted VF occurrence. Absolute BVI parameters that quantify variability of repolarization (e.g. 'short-term variability' of QT interval) had the best predictive power with high sensitivity and specificity. In contrast, VF was not predicted by any BVI parameter derived from the last arrhythmia-free interlude before VF.</AbstractText>The novel absolute BVI parameters that predicted TdP in rabbit also predict ischaemia-induced VF in rat, indicating a diagnostic and mechanistic congruence. Repolarization inhomogeneity represents a pivotal biomarker of ischaemia-induced VF. The newly validated biomarkers could serve as surrogates for VF in pre-clinical drug investigations.</AbstractText>© 2014 The British Pharmacological Society.</CopyrightInformation> |
12,262 | Application of a mortality risk score in a general population of patients with an implantable cardioverter defibrillator (ICD). | The implantable cardioverter defibrillator (ICD) is very effective in the prevention of sudden cardiac death, but its benefit is impaired by competing risks. A simple risk model to predict mortality was designed for patients with primary prevention and ischaemic cardiomyopathy. We aimed to apply this score to a general ICD population.</AbstractText>This retrospective registry study included all patients in whom an ICD was implanted at a tertiary referral hospital. Risk factors were age >70 years, QRS width >120 ms, atrial fibrillation, New York Heart Association Functional Classification class >2 and glomerular filtration rate <60 mL/min/1.73 m(2). Kaplan-Meier curves were constructed according to the presence of 0, 1, 2 and >2 risk factors.</AbstractText>The cohort consists of 1032 patients, 881 (86%) were men, mean age was 61±14 years and mean follow-up 66±46 months. 256 patients (25%) died 58±41 months after implant. The setting was secondary prevention in 498 patients (48%). No risk factors was present in 32% of patients, 1 in 27%, 2 in 20% and >2 in 21%, respectively. There was a significant and comprehensible relation between risk score and mortality. Cumulative survival was 82% in patients with 0 risk factors, 63% in those with 1, 41% in those with 2 and 23% in those with >2 risk factors (p < 0.0001). ICD therapies were documented in 421 patients (41%) without correlation to risk factors.</AbstractText>In a mixed population of primary and secondary preventive ICD carriers, application of a simple risk score predicts long-term mortality but not appropriate use of the ICD.</AbstractText> |
12,263 | Comparison of heat donation through the head or torso on mild hypothermia rewarming. | The purpose of the study was to compare the effectiveness of head vs torso warming in rewarming mildly hypothermic, vigorously shivering subjects using a similar source of heat donation.</AbstractText>Six subjects (1 female) were cooled on 3 occasions in 8 ºC water for 60 minutes or to a core temperature of 35 ºC. They were then dried, insulated, and rewarmed by 1) shivering only; 2) charcoal heater applied to the head; or 3) charcoal heater applied to the torso. The order of rewarming methods followed a balanced design. Esophageal temperature, skin temperature, heart rate, oxygen consumption, and heat flux were measured.</AbstractText>There were no significant differences in rewarming rate among the 3 conditions. Torso warming increased skin temperature and inhibited shivering heat production, thus providing similar net heat gain (268 ± 66 W) as did shivering only (355 ± 105 W). Head warming did not inhibit average shivering heat production (290 ± 72 W); it thus provided a greater net heat gain during 35 to 60 minutes of rewarming than did shivering only.</AbstractText>Head warming is as effective as torso warming for rewarming mildly hypothermic victims. Head warming may be the preferred method of rewarming in the field management of hypothermic patients if: 1) extreme conditions in which removal of the insulation and exposure of the torso to the cold is contraindicated; 2) excessive movement is contraindicated (eg, potential spinal injury or severe hypothermia that has a risk of ventricular fibrillation); or 3) if emergency personnel are working on the torso.</AbstractText>© 2013 Wilderness Medical Society Published by Wilderness Medical Society All rights reserved.</CopyrightInformation> |
12,264 | In silico investigation of a KCNQ1 mutation associated with familial atrial fibrillation. | Mutations in transmembrane domains of the KCNQ1 subunit of the I(Ks) potassium channel have been associated with familial atrial fibrillation. We have investigated mechanisms by which the S1 domain S140G KCNQ1 mutation influences atrial arrhythmia risk and, additionally, whether it can affect ventricular electrophysiology. In perforated-patch recordings, S140G-KCNQ1+KCNE1 exhibited leftward-shifted activation, slowed deactivation and marked residual current. In human atrial action potential (AP) simulations, AP duration and refractoriness were shortened and rate-dependence flattened. Simulated I(Ks) but not I(Kr) block offset AP shortening produced by the mutation. In atrial tissue simulations, temporal vulnerability to re-entry was little affected by the S140G mutation. Spatial vulnerability was markedly increased, leading to more stable and stationary spiral wave re-entry in 2D stimulations, which was offset by I(Ks) block, and to scroll waves in 3D simulations. These changes account for vulnerability to AF with this mutation. Ventricular AP clamp experiments indicate a propensity for increased ventricular I(Ks) with the S140G KCNQ1 mutation and ventricular AP simulations showed model-dependent ventricular AP abbreviation. |
12,265 | Short term administration of L-carnitine can be detrimental to the ischemic heart. | Previous studies have shown that L-carnitine (LC) supplementation may exert a cardioprotective effect in cardiomyopathy, prevent arrhythmias in myocardial infarction and increase exercise tolerance in angina. Interestingly, we demonstrated that short term preischemic administration of LC can be detrimental to ischemic heart. In isolated rat hearts treated with LC for 10 min before ischemia, a marked and concentration dependent arrhythmogenic activity were produced during both ischemia and reperfusion as increases in the number of ventricular ectopic beats, ventricular tachycardia and incidence of ventricular fibrillation. We hypothesized that preischemic using of LC for an inadequate time may pose arrhythmogenic activity, due to incomplete metabolism of fatty acids which in turn lead to production of toxic long chain fatty acid metabolites and also because of interruption in glucose oxidation. |
12,266 | Marathon run: cardiovascular adaptation and cardiovascular risk. | The first marathon run as an athletic event took place in the context of the Olympic Games in 1896 in Athens, Greece. Today, participation in a 'marathon run' has become a global phenomenon attracting young professional athletes as well as millions of mainly middle-aged amateur athletes worldwide each year. One of the main motives for these amateur marathon runners is the expectation that endurance exercise (EE) delivers profound beneficial health effects. However, with respect to the cardiovascular system, a controversial debate has emerged whether the marathon run itself is healthy or potentially harmful to the cardiovascular system, especially in middle-aged non-elite male amateur runners. In this cohort, exercise-induced increases in cardiac biomarkers-troponin and brain natriuretic peptide-and acute functional cardiac alterations have been observed and interpreted as potential cardiac damage. Furthermore, in the cohort of 40- to 65-year-old males engaged in intensive EE, a significant risk for the development of atrial fibrillation has been identified. Fortunately, recent studies demonstrated a normalization of the cardiac biomarkers and the functional alterations within a short time frame. Therefore, these alterations may be perceived as physiological myocardial reactions to the strenuous exercise and the term 'cardiac fatigue' has been coined. This interpretation is supported by a recent analysis of 10.9 million marathon runners demonstrating that there was no significantly increased overall risk of cardiac arrest during long-distance running races. In conclusion, intensive and long-lasting EE, e.g. running a full-distance Marathon, results in high cardiovascular strain whose clinical relevance especially for middle-aged and older athletes is unclear and remains a matter of controversy. Furthermore, there is a need for evidence-based recommendations with respect to medical screening and training strategies especially in male amateur runners over the age of 35 years engaged in regular and intensive EE. |
12,267 | Intravenous metoprolol versus diltiazem for rate control in noncardiac, nonthoracic postoperative atrial fibrillation. | Little guidance exists on effective management of postoperative atrial fibrillation (POAF) following noncardiac, nonthoracic (NCNT) surgery.</AbstractText>The purpose of this study was to identify whether a difference exists between intravenous (IV) metoprolol and diltiazem when used to achieve hemodynamically stable rate control in POAF following NCNT surgery.</AbstractText>This retrospective cohort study examined critically ill adult surgical patients experiencing POAF with rapid ventricular response. Inclusion in the metoprolol or diltiazem treatment group was determined by the initial rate control agent chosen by the prescriber. The primary end point was hemodynamically stable rate control, defined by heart rate (HR) <110 beats/min and blood pressure >90 mm Hg, maintained for 6 hours.</AbstractText>Patients on metoprolol (n = 66) and diltiazem (n = 55) were similar in age, comorbidities, surgical procedure distribution, acuity of illness, and home rate and rhythm control medications continued during hospitalization; 76% of diltiazem-treated patients achieved hemodynamically stable rate control, compared with only 53% of those receiving metoprolol (P = .005). Safety end points were similar between groups, including the portion requiring a new vasopressor or fluid bolus for hemodynamic support.</AbstractText>In NCNT surgery, patients with POAF, IV diltiazem more effectively controlled HR and hemodynamics compared with metoprolol. Results warrant further research into optimal medical management of POAF in this population using these 2 agents.</AbstractText> |
12,268 | The effect of mild left ventricular diastolic dysfunction on outcome after isolated coronary bypass surgery. | Although moderate to severe diastolic dysfunction (DD) seems to be associated with poor prognosis after isolated coronary bypass surgery, the impact of mild DD has not been investigated extensively in this group of patients.</AbstractText>We evaluated the prognostic implication of mild left ventricular (LV) DD on outcome after isolated coronary bypass surgery in patients with preserved LV systolic function.</AbstractText>Data from 650 patients undergoing isolated coronary bypass surgery and having records for LV diastolic function between January 2009 and August 2011 was collected retrospectively. DD was classified as mild (grade 1, impaired relaxation), moderate (grade 2, decreased compliance) or severe (grade 3-4, restrictive pattern) depending on mitral inflow wave, tissue Doppler imaging, and pulmonary vein flow wave. Patients with baseline rhythm other than sinus, moderate or severe valvular dysfunction, moderate or severe diastolic dysfunction, and LV ejection fraction lower than 50% were excluded. A total of 472 patients were identified within the database fulfilling the eligibility criteria for this analysis and stratified according to the echocardiographic findings as follows: group 1 comprised patients with normal diastolic function (n = 168); and group 2 was made up of patients with mild DD (impaired relaxation) (n = 304). These groups were compared for perioperative morbidity and mortality.</AbstractText>The preoperative variables were comparable between groups. The outcome parameters of group 1 was similar compared to group 2 in terms of need for inotropic support (20.2% vs. 16.2%), intra-aortic balloon pump usage (0% vs. 1.4%), mechanical ventilation time (8.94 ± 0.96 h vs. 10.0 ± 0.89 h), reintubation rate (1.8% vs. 1.4%), intensive care unit stay time (24.1 ± 1.4 hvs. 26.2 ± 1.9 h), postoperative renal failure rate (0% vs. 0.3%), postoperative atrial fibrillation rate (10.1% vs. 11.2%), length of hospital stay (7.19 ± 0.45 vs. 6.57 ± 0.14 days), hospital readmission rate (3.1% vs. 3.1%), and mortality (0% vs. 1.6%).</AbstractText>The results from this study indicate that mild LV DD is not associated with adverse outcome after coronary bypass surgery in patients with preserved LV systolic function, thus should not be considered as a preoperative risk factor.</AbstractText> |
12,269 | Brain natriuretic peptide: a biomarker for all cardiac disease? | To evaluate new development in the utility of brain natriuretic peptide and N-Terminal brain natriuretic peptide (BNP/NT-Pro-BNP) in the management of various cardiovascular diseases. The determination of plasma BNP levels has an established role in the discrimination of pulmonary oedema from other causes of acute dyspnoea, and there is increasing evidence of the utility of BNP/NT-Pro-BNP assay both as a prognostic tool in chronic heart failure and as a means of guiding therapy in heart failure patients aged below 70 years.</AbstractText>Findings have substantially extended the clinical utility of BNP/NT-Pro-BNP assay. In heart failure with preserved left ventricular ejection fraction, BNP elevation may also facilitate diagnosis, although its precise utility is uncertain.In the acute catecholamine-induced myocardial inflammatory condition of Tako-Tsubo cardiomyopathy (TTC), BNP/NT-Pro-BNP elevations are marked and persist for at least 3 months, despite the absence of pulmonary oedema. In TTC, BNP/NT-Pro-BNP therefore serves as an ancillary diagnostic measure as well as a marker of recovery. Among other conditions in which BNP assay may provide prognostic information are atrial fibrillation (in which the extent of elevation predicts thromboembolic risk) and pulmonary hypertension.</AbstractText>BNP/NT-Pro-BNP assay has widespread utility as an adjunct to cardiovascular disease diagnosis and management.</AbstractText> |
12,270 | Dantrolene improves survival after ventricular fibrillation by mitigating impaired calcium handling in animal models. | Resistant ventricular fibrillation, refibrillation. and diminished myocardial contractility are important factors leading to poor survival after cardiac arrest. We hypothesized that dantrolene improves survival after ventricular fibrillation (VF) by rectifying the calcium dysregulation caused by VF.</AbstractText>VF was induced in 26 Yorkshire pigs for 4 minutes. Cardiopulmonary resuscitation was then commenced for 3 minutes, and dantrolene or isotonic saline was infused at the onset of cardiopulmonary resuscitation. Animals were defibrillated and observed for 30 minutes. To study the effect of VF on calcium handling and its modulation by dantrolene, hearts from 14 New Zealand rabbits were Langendorff-perfused. The inducibility of VF after dantrolene administration was documented. Optical mapping was performed to evaluate diastolic spontaneous calcium elevations as a measure of cytosolic calcium leak. The sustained return of spontaneous circulation (systolic blood pressure ≥60 mm Hg) was achieved in 85% of the dantrolene group in comparison with 39% of controls (P=0.02). return of spontaneous circulation was achieved earlier in dantrolene-treated pigs after successful defibrillation (21 ± 6 s versus 181 ± 57 s in controls, P=0.005). The median number of refibrillation episodes was lower in the dantrolene group (0 versus 1, P=0.04). In isolated rabbit hearts, the successful induction of VF was achieved in 83% of attempts in controls versus 41% in dantrolene-treated hearts (P=0.007). VF caused diastolic calcium leaks in the form of spontaneous calcium elevations. Administration of 20 μmol/L dantrolene significantly decreased spontaneous calcium elevation amplitude versus controls. (0.024 ± 0.013 versus 0.12 ± 0.02 arbitrary unit [200-ms cycle length], P=0.001).</AbstractText>Dantrolene infusion during cardiopulmonary resuscitation facilitates successful defibrillation, improves hemodynamics postdefibrillation, decreases refibrillation, and thus improves survival after cardiac arrest. The effects are mediated through normalizing VF-induced dysfunctional calcium cycling.</AbstractText> |
12,271 | Kcne2 deletion creates a multisystem syndrome predisposing to sudden cardiac death. | Sudden cardiac death (SCD) is the leading global cause of mortality, exhibiting increased incidence in patients with diabetes mellitus. Ion channel gene perturbations provide a well-established ventricular arrhythmogenic substrate for SCD. However, most arrhythmia-susceptibility genes, including the KCNE2 K(+) channel β subunit, are expressed in multiple tissues, suggesting potential multiplex SCD substrates.</AbstractText>Using whole-transcript transcriptomics, we uncovered cardiac angiotensinogen upregulation and remodeling of cardiac angiotensinogen interaction networks in P21 Kcne2(-/-) mouse pups and adrenal remodeling consistent with metabolic syndrome in adult Kcne2(-/-) mice. This led to the discovery that Kcne2 disruption causes multiple acknowledged SCD substrates of extracardiac origin: diabetes mellitus, hypercholesterolemia, hyperkalemia, anemia, and elevated angiotensin II. Kcne2 deletion was also a prerequisite for aging-dependent QT prolongation, ventricular fibrillation and SCD immediately after transient ischemia, and fasting-dependent hypoglycemia, myocardial ischemia, and AV block.</AbstractText>Disruption of a single, widely expressed arrhythmia-susceptibility gene can generate a multisystem syndrome comprising manifold electric and systemic substrates and triggers of SCD. This paradigm is expected to apply to other arrhythmia-susceptibility genes, the majority of which encode ubiquitously expressed ion channel subunits or regulatory proteins.</AbstractText> |
12,272 | Resuscitation of a neonate with medium chain acyl-coenzyme a dehydrogenase deficiency using extracorporeal life support. | We report a neonate with medium chain acyl-coenzyme A dehydrogenase deficiency (MCAD) who had a cardiac arrest due to ventricular tachycardia and fibrillation. Extracorporeal life support (ECLS) was deployed, from which the baby was subsequently separated and discharged from hospital. This case was a rare neonatal presentation of MCAD and an uncommon indication for ECLS. We discuss the presentations of patients with MCAD and the use of ECLS for patients with possible inborn errors of metabolism and other unknown primary diagnoses. |
12,273 | Survival with good neurological outcome in a patient with prolonged ischemic cardiac arrest--utility of automated chest compression systems in the cardiac catheterization laboratory. | The management of refractory cardiac arrest during invasive coronary procedures has substantial logistical challenges and is typically associated with disappointing outcomes. We describe the case of a young woman with recalcitrant ventricular fibrillation due to acute anterior ST-elevation myocardial infarction caused by occlusion of her proximal left anterior descending artery. Survival without neurological deficit or organ failure was achieved following primary percutaneous reperfusion and a total of 52 min of intra-procedural chest compression support, made possible by the use of an automated chest compression device. |
12,274 | Multiple and recurrent coronary stent fractures. | Coronary stent fracture is an increasingly recognized complication mainly involving drug-eluting stents. Important clinical implications, including in-stent restenosis and stent thrombosis, have been associated with this phenomenon. Variable incidence rates and several predisposing factors have been reported, but no general agreement exists on the best treatment strategy. We report a case of recurrent multiple left anterior descending artery sirolimus-eluting stent fractures, with variable clinical presentations ranging from recurrent angina to acute myocardial infarction and ventricular fibrillation cardiac arrest, that were ultimately treated with coronary artery bypass surgery. |
12,275 | Use of novel oral anticoagulants in patients with heart failure. | Pathophysiologically, there is a prothrombotic state evident in heart failure (HF). This is particularly evident within atria in patients whose course of the disease is complicated by concomitant atrial fibrillation (AF). A predisposition for thrombogenesis exists in patients with dilated dysfunctional cardiac chambers, such as those seen in patients with large myocardial infarction, left ventricular (LV) aneurysm or dilated cardiomyopathy. Based on subgroup analyses of recent phase 3 randomized trials, the novel oral anticoagulants are equally effective and safe in AF patients with HF or without HF. This appears to be true regarding both HF with systolic LV dysfunction and with preserved LVEF. However, patients with HF with preserved LVEF with more strict definition (ie, LVEF ≥ 55 %) have not been analyzed specifically. There is no information from clinical trial regarding possible utility of the novel oral anticoagulants in HF patients in sinus rhythm. Further research is required to cover gaps in knowledge on utility of these medications in a substantial proportion of HF patients not included in major clinical trials on novel oral anticoagulants. |
12,276 | Probability of a shockable presenting rhythm as a function of EMS response time. | Survival from cardiac arrest is associated with having a shockable presenting rhythm (VF/pulseless VT) upon EMS arrival. A concern is that several studies have reported a decline in the incidence of VF/PVT over the past few decades. One plausible explanation is that contemporary cardiovascular therapies, such as increased use of statin and beta blocker drugs, may shorten the duration of VF/PVT after arrest. As a result, EMS response time would become an increasingly important factor in the likelihood of a shockable presenting rhythm, and consequently, cardiac arrest survival.</AbstractText>To develop a model describing the likelihood of shockable presenting rhythm as a function of EMS response time.</AbstractText>We conducted a retrospective observational study of cardiac arrest using the North Carolina Prehospital Care Reporting System (PreMIS). Inclusionary criteria consisted of adult patients suffering nontraumatic cardiac arrests witnessed by a layperson between January 1 and June 30, 2012. Patients defibrillated prior to EMS arrival were excluded. Chi-square and t-tests were used to analyze the relationship between shockable presenting rhythm and patient age, gender, and race; response time measured as elapsed minutes between 9-1-1 call receipt and scene arrival; and bystander CPR. Logistic regression was used to calculate the adjusted odds ratio (OR) of shockable presenting rhythm as a function of response time while controlling for statistically significant covariates.</AbstractText>A total of 599 patients met inclusion criteria. Overall, VF/PVT was observed in 159 patients (26.5%). VF/PVT was less likely with increasing EMS response time (OR 0.92, 95% CI = 0.87-0.97, p < 0.01) and age (OR 0.98, 95% CI = 0.97-0.99, p < 0.01), while males (OR 1.98, 95% CI = 1.29-3.03, p < 0.01) and Caucasians (OR 1.86, 95% CI = 1.17-2.95, p < 0.01) were more likely to have shockable presenting rhythm. Bystander CPR was not associated with shockable presenting rhythm, although EMS response time was longer among patients with bystander CPR compared to those without (9.83 vs. 8.83 minutes, p < 0.01).</AbstractText>We found that for every one minute of added ambulance response time, the odds of shockable presenting rhythm declined by 8%. This information could prove useful for EMS managers tasked with developing EMS system response strategies for cardiac arrest management.</AbstractText> |
12,277 | Osteopontin and galectin-3 predict the risk of ventricular tachycardia and fibrillation in heart failure patients with implantable defibrillators. | Myocardial extracellular matrix remodelling provides electrical heterogeneity entailing ventricular tachycardia/fibrillation (VT/VF) in heart failure (HF) patients. Osteopontin (OPN) and Galectin-3 (Gal-3) are fibrosis markers and may reflect the extension of the arrhythmogenic substrate. We assessed whether plasma OPN and Gal-3 predict the risk of sustained VT/VF in a cohort of HF patients with implantable cardioverter-defibrillator (ICD).</AbstractText>A total of 75 HF patients underwent pre-ICD implantation clinical evaluation and assessment of plasma OPN and Gal-3. The primary endpoint was the time to the occurrence of the first sustained VT/VF. Hazard ratios (HR) were derived from Cox proportional-hazards analysis.</AbstractText>Patients with coronary artery disease (CAD) had higher plasma OPN (79.8 ± 44.0 ng/mL vs. 66.0 ± 31.8 ng/mL; P = 0.04). Both Gal-3 (r = -0.38; P = 0.01) and OPN (r = -0.27; p = 0.01) were negatively related to estimated glomerular filtration rate. After 29 ± 17 months, 20 patients (27%) reached the primary endpoint. Patients with VT/VF had higher plasma OPN and Gal-3 (97.4 ± 51.7 ng/mL vs. 65.9 ± 31.3 ng/mL; P = 0.002 and 19.7 ± 8.5 ng/mL vs. 16.2 ± 6.2 ng/mL; P = 0.05). In univariate analysis, OPN (log-OPN, HR: 32.4; 95%CI: 3.9-264.7; P = 0.001) and Gal-3 (HR: 1.05; 95%CI: 1.00-1.11; P = 0.04) predicted sustained VT/VF. In multivariable analysis, both OPN (HR: 41.4; 95%CI: 3.8-441.9; P = 0.002) and Gal-3 (HR: 1.06; 95%CI: 1.00-1.12; P = 0.03) retained their prognostic power after correction for age, sex, history of MI, EF, NYHA class, eGFR, use of ACE-I, and amiodarone.</AbstractText>Plasma OPN and Gal-3 predict sustained VT/VF in HF patients at high risk for SCD. Larger prospective studies should outline the role of these biomarkers in predicting SCD on top of conventional risk stratification.</AbstractText>© 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
12,278 | Gain-of-function KCNH2 mutations in patients with Brugada syndrome. | Brugada syndrome (BrS) is an inherited disease characterized by right precordial ST segment elevation on electrocardiograms (ECGs) that predisposes patients to sudden cardiac death as a result of polymorphic ventricular tachyarrhythmia or ventricular fibrillation (VF). In BrS patients, except for SCN5A, mutations in other responsible genes are poorly elucidated.</AbstractText>We identified 4 KCNH2 mutations, T152I, R164C, W927G, and R1135H, in 236 consecutive probands with BrS or Brugada-like ECG. Three of these mutation carriers showed QTc intervals shorter than 360 milliseconds and 1 experienced VF. We performed patch-clamp analyses on I(Kr) reconstituted with the KCNH2 mutations in Chinese hamster ovary cells and compared the phenotypes of the patients with different genotypes. Three mutations, R164C, W927G, and R1135H, increased I(Kr) densities. Three mutations, T152I, R164C, and W927G, caused a negative shift in voltage-dependent activation curves. Only the R1135H mutant channel prolonged the deactivation time constants. We also identified 20 SCN5A and 5 CACNA1C mutation carriers in our cohort. Comparison of probands' phenotypes with 3 different genotypes revealed that KCNH2 mutation carriers showed shorter QTc intervals and SCN5A mutation carriers had longer QRS durations.</AbstractText>All KCNH2 mutations that we identified in probands with BrS exerted gain-of-function effects on I(Kr) channels, which may partially explain the ECG findings in our patients.</AbstractText>© 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
12,279 | Congenital Long QT Syndrome: An Update and Present Perspective in Saudi Arabia. | Primary cardiac arrhythmias are often caused by defects, predominantly in the genes responsible for generation of cardiac electrical potential, i.e., cardiac rhythm generation. Due to the variability in underlying genetic defects, type, and location of the mutations and putative modifiers, clinical phenotypes could be moderate to severe, even absent in many individuals. Clinical presentation and severity could be quite variable, syncope, or sudden cardiac death could also be the first and the only manifestation in a patient who had previously no symptoms at all. Despite usual familial occurrence of such cardiac arrhythmias, disease causal genetic defects could also be de novo in significant number of patients. Long QT syndrome (LQTS) is the most eloquently investigated primary cardiac rhythm disorder. A genetic defect can be identified in ∼70% of definitive LQTS patients, followed by Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) and Brugada syndrome (BrS), where a genetic defect is found in <40% cases. In addition to these widely investigated hereditary arrhythmia syndromes, there remain many other relatively less common arrhythmia syndromes, where researchers also have unraveled the genetic etiology, e.g., short QT syndrome (SQTS), sick sinus syndrome (SSS), cardiac conduction defect (CCD), idiopathic ventricular fibrillation (IVF), early repolarization syndrome (ERS). There exist also various other ill-defined primary cardiac rhythm disorders with strong genetic and familial predisposition. In the present review we will focus on the genetic basis of LQTS and its clinical management. We will also discuss the presently available genetic insight in this context from Saudi Arabia. |
12,280 | Profile of cardiac disease in Cameroon and impact on health care services. | Cardiovascular diseases (CVD) have emerged as a major public health problem and impose an escalating burden on the health care system in Cameroon. The aim of the study was to investigate the preparedness of health care services for patients presenting with CVD in general and specifically, in St. Elizabeth catholic general hospital Shisong, cardiac centre.</AbstractText>Between November 2009 and November 2011, a population of 8,389 adults and 706 children consulted the referral cardiac centre of St. Elizabeth Catholic General Hospital. The patients' age ranges between 5 days and 103 years old, with a mean of 48.7±18 years. Female represented 54.2% of the total population.</AbstractText>Hypertension was diagnosed in 41.5% of patients. Isolated systolic hypertension was rarely found (4.2%) and 45.2% of patients were classified as class II according to the JNC7. Congestive heart failure was diagnosed in 29.6%. Forty-four percent of patients were in class III and 7% in class IV heart failure (NYHA). Arrhythmia was seen in 12.2% cases, with atrial fibrillation in 35.2%, followed by ventricular ectopic beats in 20.3%. Stable angina was diagnosed in 1.5%, and acute myocardial infarction 0.9%. In children, the prevalence of congenital heart disease was (4.3%). The disease the most detected was isolated ventricular septal defect, followed by tetralogy of Fallot. Post rheumatic valvulopathies were the main cause of heart failure in teenagers and young adults. Valve replacement with a mechanical valve was performed in 110 patients, valvuloplasty in eight patients, and surgical correction of congenital heart diseases in 105 cases.</AbstractText>Our data, collected in a rural area, shows the high prevalence of hypertension in rural sub-Saharan Africa. Congestive heart failure mainly due to post rheumatic valvulopathies is common amongst children and young adults.</AbstractText> |
12,281 | Catheter ablation of ventricular fibrillation: importance of left ventricular outflow tract and papillary muscle triggers. | Monomorphic ventricular premature depolarizations (VPDs) have been found to initiate ventricular fibrillation (VF) or polymorphic ventricular tachycardia (PMVT) in patients with and without structural heart disease.</AbstractText>The purpose of this study was to describe and characterize sites of origin of VPDs triggering VF and PMVT.</AbstractText>The distribution of mapping-confirmed VPDs, electrophysiology laboratory findings, and results of radiofrequency catheter ablation were analyzed.</AbstractText>Among 1132 consecutive patients who underwent ablation for ventricular arrhythmias, 30 patients (2.7%) with documented VF/PMVT initiation were identified. In 21 patients, VF/PMVT occurred in the setting of cardiomyopathy; in 9 patients, VF/PMVT was idiopathic. The origin of VPD trigger was from the Purkinje network in 9, papillary muscles in 8, left ventricular outflow tract in 9, and other low-voltage areas unrelated to Purkinje activity in 4. Each distinct anatomic area of origin was associated with VF/PMVT triggers in patients with and without heart disease. Acute VPD elimination was achieved in 26 patients (87%), with a decrease in VPDs in another 3 patients (97%). During median follow-up of 418 days (interquartile range [IQR] 144-866), 5 patients developed a VF/PMVT recurrence after a median of 34 days (IQR 1-259). Rare recurrence was noted in patients with and without structural disease and from each distinct anatomic origin. The total burden of VF/PMVT episodes/shocks was reduced from a median of 9 (IQR 2.5-22.5) in the 3 months before ablation to 0 (IQR 0-0, total range 0-2) during follow-up (P <.0001).</AbstractText>Catheter ablation of VPD-triggered VF/PMVT is highly successful. Left ventricular outflow tract and papillary muscles are common and are previously unrecognized sites of origin of these triggers in patients with and without structural heart disease.</AbstractText>Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,282 | Predictors of long-term outcomes in patients with significant myxomatous mitral regurgitation undergoing exercise echocardiography. | Significant myxomatous mitral regurgitation leads to progressive left ventricular (LV) decline, resulting in congestive heart failure and death. Such patients benefit from mitral valve surgery. Exercise echocardiography aids in risk stratification and helps decide surgical timing. We sought to assess predictors of outcomes in such patients undergoing exercise echocardiography.</AbstractText>This is an observational study of 884 consecutive patients (age, 58 ± 14 years; 67% men) with grade III+ or greater myxomatous mitral regurgitation who underwent exercise echocardiography between January 2000 and December 2011 (excluding functional mitral regurgitation, prior valvular surgery, hypertrophic cardiomyopathy, rheumatic valvular disease, or greater than mild mitral stenosis). Clinical and echocardiographic data (mitral regurgitation, LV ejection fraction, LV dimensions, right ventricular systolic pressure) and exercise variables (metabolic equivalents, heart rate recovery at 1 minute after exercise) were recorded. Composite events of death, myocardial infarction, stroke, and progression to congestive heart failure were recorded. Mean LV ejection fraction, indexed LV end-systolic dimension, resting right ventricular systolic pressure, peak stress right ventricular systolic pressure, metabolic equivalents achieved, and heart rate recovery were 58 ± 5%, 1.6 ± 0.4 mm/m(2), 31 ± 12 mm Hg, 46 ± 17 mm Hg, 9.6 ± 3, and 33 ± 14 beats, respectively. During 6.4 ± 4 years of follow-up, there were 87 events. On stepwise multivariable Cox analysis, percent of age/sex-predicted metabolic equivalents (hazard ratio, 0.99; 95% confidence interval, 0.98-0.99; P=0.005), heart rate recovery (hazard ratio, 0.29; 95% confidence interval, 0.17-0.50; P<0.001), resting right ventricular systolic pressure (hazard ratio, 1.03; 95% confidence interval, 1.004-1.05; P=0.02), atrial fibrillation (hazard ratio, 1.91; 95% confidence interval, 1.07-3.41; P=0.03), and LV ejection fraction (hazard ratio, 0.96; 95% confidence interval, 0.92-0.99; P=0.04) predicted outcomes.</AbstractText>In patients with grade III+ or greater myxomatous mitral regurgitation undergoing exercise echocardiography, lower percent of age/sex-predicted metabolic equivalents, lower heart rate recovery, atrial fibrillation, lower LV ejection fraction, and high resting right ventricular systolic pressure predicted worse outcomes.</AbstractText> |
12,283 | Cardioembolic stroke: practical considerations for patient risk management and secondary prevention. | Cardioembolic (CE) stroke constitutes approximately 20% of all occurrence of ischemic stroke in patients. Atrial fibrillation remains the most common and most studied mechanism underlying CE stroke events. Cardioembolic strokes carry high morbidity and are associated with early recurrence in patients. Our understanding of other patient mechanisms associated with CE stroke, including valvular disease, left ventricular dysfunction, and patent foramen ovale, continues to grow. Our review summarizes the diagnosis and management of patients who have sustained CE stroke as a result of the aforementioned cardiac mechanisms. Advances in primary and secondary risk management for prevention of CE stroke are also highlighted in our article-specifically, emerging data regarding monitoring of patients with atrial fibrillation, new anticoagulation therapy, and management of patients with decreased ejection fraction. |
12,284 | Predictors of severe tricuspid regurgitation in patients with permanent pacemaker or automatic implantable cardioverter-defibrillator leads. | Patients with permanent pacemaker or automatic implantable cardioverter-defibrillator (AICD) leads have an increased prevalence of tricuspid regurgitation. However, the roles of cardiac rhythm and lead-placement duration in the development of severe tricuspid regurgitation are unclear. We reviewed echocardiographic data on 26 consecutive patients who had severe tricuspid regurgitation after permanent pacemaker or AICD placement; before treatment, they had no organic tricuspid valve disease, pulmonary hypertension, left ventricular dysfunction, or severe tricuspid regurgitation. We compared the results to those of 26 control subjects who had these same devices but no more than mild tricuspid regurgitation. The patients and control subjects were similar in age (mean, 81 ±6 vs 81 ±8 yr; P = 0.83), sex (male, 42% vs 46%; P = 0.78), and left ventricular ejection fraction (0.60 ±0.06 vs 0.58 ± 0.05; P = 0.4). The patients had a higher prevalence of atrial fibrillation (92% vs 65%; P=0.01) and longer median duration of pacemaker or AICD lead placement (49.5 vs 5 mo; P < 0.001). After adjusting for age, sex, and right ventricular systolic pressure by multivariate logistic regression analysis, we found that atrial fibrillation (odds ratio=6.4; P = 0.03) and duration of lead placement (odds ratio=1.5/yr; P = 0.001) were independently associated with severe tricuspid regurgitation. Out study shows that atrial fibrillation and longer durations of lead placement might increase the risk of severe tricuspid regurgitation in patients with permanent pacemakers or AICDs. |
12,285 | Changes in medication preceding out-of-hospital cardiac arrest where resuscitation was attempted. | To describe recent changes in medication preceding out-of-hospital cardiac arrest (OHCA) where resuscitation was attempted.</AbstractText>OHCA victims were identified by the Swedish Cardiac Arrest Register and linked by means of their unique 10-digit personal identification numbers to the Prescribed Drug Register. We identified new claimed prescriptions during a 6-month period before the OHCA compared with those claimed in the period 12 to 18 months before. The 7-digit Anatomical Therapeutical Chemical codes of individual drugs were used. The study period was November 2007-January 2011.</AbstractText>OHCA victims with drugs were (1) older than those who did not claim any drugs in any period (70 ± 16 years vs. 54 ± 22 years, P < 0.001), (2) more often women (34% vs. 20%, P < 0.001), and (3) had more often a presumed cardiac etiology (67% vs. 54%, P < 0.001). The OHCA victims were less likely to have ventricular tachycardia/ventricular fibrillation as the first recorded rhythm (26% vs. 33%, P < 0.001) or to survive 1 month (9% vs. 17%, P < 0.0001). New prescriptions were claimed by 5122 (71%) of 7243 OHCA victims. The most frequently claimed new drugs were paracetamol (acetaminophen) 10.3%, furosemide 7.8%, and omeprazole 7.6%. Of drugs known or supposed to cause QT prolongation, ciprofloxacin was the most frequent (3.4%) altogether; 16% had a new claimed prescription of a drug included in the "qtdrugs.org" lists.</AbstractText>Most OHCA victims had new drugs prescribed within 6 months before the event but most often intended for diseases other than cardiac. No claims can be made as to the causality.</AbstractText> |
12,286 | Comparison of nifekalant and amiodarone for resuscitation of out-of-hospital cardiopulmonary arrest resulting from shock-resistant ventricular fibrillation. | Nifekalant is a pure potassium channel blocker that has been used to treat ventricular tachyarrhythmias since 1999 in Japan. Intravenous amiodarone was approved later than nifekalant in Japan, and it is still unclear which of the two agents is superior. The aim of this study was to compare the efficacy of nifekalant and amiodarone for resuscitation of out-of-hospital cardiopulmonary arrest caused by shock-resistant ventricular fibrillation.</AbstractText>From December 2005 to January 2011, ambulance services transported 283 out-of-hospital cardiopulmonary arrest patients to our hospital. Of these, 25 patients were treated with nifekalant or amiodarone in response to ventricular fibrillation that was resistant to two or more shocks. We undertook a retrospective analysis of these 25 patients.</AbstractText>We enrolled 20 men and 5 women with a mean age (± standard deviation) of 61.1 ± 16.4 years. All 25 patients were treated with tracheal intubation and intravenous epinephrine. Fourteen patients received nifekalant and 11 patients received amiodarone. The rates of return of spontaneous circulation (ROSC) (nifekalant, 5/14, versus amiodarone, 4/11; P = 0.97) and survival to discharge (nifekalant, 4/14, versus amiodarone, 2/11; P = 0.89) were not significantly different between the two groups. The time from nifekalant or amiodarone administration to ROSC was 6.0 ± 6.6 and 20.3 ± 10.0 min, respectively, which was significantly different (P < 0.05).</AbstractText>In this small sample size study, nifekalant, compared with amiodarone, is equally effective for ROSC and survival to discharge after shock-resistant ventricular fibrillation and can achieve ROSC more quickly. Further prospective studies are needed to confirm our results.</AbstractText> |
12,287 | ST-elevation myocardial infarction diagnosed after hospital admission. | Treatment times for ST-elevation myocardial infarction (STEMI) patients presenting to percutaneous coronary intervention hospitals have improved dramatically over the past 10 years, particularly for patients using emergency medical services. Limited data exist regarding treatment times and outcomes for patients who develop STEMI after hospital admission.</AbstractText>With the use of a comprehensive prospective regional STEMI program database, we evaluated the characteristics and outcomes for patients who develop STEMI after hospital admission. Of the 3795 consecutive STEMI patients treated by the use of the Minneapolis Heart Institute regional STEMI program from March 2003 to January 2013, 990 (26.1%) presented initially to the percutaneous coronary intervention facility, including 640 arriving via emergency medical services, 267 self/family driven, and 83 already admitted to the hospital. Patients with in-hospital presentation were older with higher body mass indexes, were more likely to have hypertension, and to present with pre-percutaneous coronary intervention cardiac arrest and cardiogenic shock. Door-to-balloon times (diagnostic ECG-to-balloon for in-hospital patients) were longer than for patients using emergency medical services (76 versus 51 minutes; P<0.001), but similar to self/family-driven patients (76 versus 66 minutes; P=0.13). In-hospital patients had longer lengths of stay (5 versus 3 versus 3 days; P<0.001) and higher 1-year mortality (16.9% versus 10.3% versus 7.1%; P=0.032). These patients frequently had high-risk and complex reasons for admission, including 30.1% with acute coronary syndrome, 22.9% postsurgery, 13.3% respiratory failure, and 8.4% ventricular fibrillation.</AbstractText>Patients who develop STEMI while in-hospital represent a unique, high-risk subset of patients. They have increased treatment time and lengths of stay and higher mortality rates than the patients presenting via emergency medical services or who are self/family driven.</AbstractText> |
12,288 | Piceatannol facilitates conduction block and ventricular fibrillation induction in ischemia-reperfused rabbit hearts with pacing-induced heart failure. | Piceatannol, a hydroxystilbene natural product, has been reported to exert antiarrhythmic action via INa inhibition and slow INa inactivation in ischemia-reperfused (IR) rat hearts. The present study aimed to clarify the proarrhythmic property of piceatannol during regional IR injury in failing rabbit hearts.</AbstractText>Heart failure (HF) was induced by rapid right ventricular pacing for 4 weeks. The IR model was created by coronary artery ligation for 30 min, followed by reperfusion for 15 min in vivo. Simultaneous voltage and intracellular Ca(2+) (Cai) optical mapping was then performed in isolated Langendorff-perfused hearts (n=11 in each HF and control group). Action potential duration (APD) restitution, arrhythmogenic alternans and VF inducibility were evaluated by a dynamic pacing protocol. Conduction velocity was measured along lines across the IR and non-IR zones during pacing. Piceatannol (10 μM) was administered after baseline studies.</AbstractText>In the HF group, piceatannol decreased conduction velocity, induced rate-dependent regional inhomogeneity of conduction delay and wavelength shortening, slowed Cai decay, and facilitated arrhythmogenic alternans instead of APD prolongation to increase VF inducibility. In the control group, the proarrhythmic effects of piceatannol on APD restitution, arrhythmogenic alternans and conduction delay were offset by its antiarrhythmic effects (APD and wavelength prolongation), resulting in a neutral effect on VF inducibility.</AbstractText>Piceatannol (10 μM) is proarrhythmic in failing rabbit hearts with regional IR injury. The increased VF inducibility by piceatannol in HF suggests that its undesirable effects are more pronounced than its benefits in failing hearts.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,289 | Ventricular fibrillation in a patient with tachycardia-induced cardiomyopathy after liver transplantation. | We report a case of atrial fibrillation-related tachycardia induced cardiomyopathy and ventricular fibrillation after liver transplantation in a 41-year-old man with end-stage liver failure. Atrial fibrillation and congestive heart failure occurred postoperatively. Cardiac arrests due to ventricular fibrillation occurred 6 months after the operation with subsequent implantations of an implantable cardioverter-defibrillator. Ventricular arrhythmias did not recur during the 18 months after normalization of heart functions with guideline-directed medical treatments. |
12,290 | Comparison of 24-hour Holter monitoring with 14-day novel adhesive patch electrocardiographic monitoring. | Cardiac arrhythmias are remarkably common and routinely go undiagnosed because they are often transient and asymptomatic. Effective diagnosis and treatment can substantially reduce the morbidity and mortality associated with cardiac arrhythmias. The Zio Patch (iRhythm Technologies, Inc, San Francisco, Calif) is a novel, single-lead electrocardiographic (ECG), lightweight, Food and Drug Administration-cleared, continuously recording ambulatory adhesive patch monitor suitable for detecting cardiac arrhythmias in patients referred for ambulatory ECG monitoring.</AbstractText>A total of 146 patients referred for evaluation of cardiac arrhythmia underwent simultaneous ambulatory ECG recording with a conventional 24-hour Holter monitor and a 14-day adhesive patch monitor. The primary outcome of the study was to compare the detection arrhythmia events over total wear time for both devices. Arrhythmia events were defined as detection of any 1 of 6 arrhythmias, including supraventricular tachycardia, atrial fibrillation/flutter, pause greater than 3 seconds, atrioventricular block, ventricular tachycardia, or polymorphic ventricular tachycardia/ventricular fibrillation. McNemar's tests were used to compare the matched pairs of data from the Holter and the adhesive patch monitor.</AbstractText>Over the total wear time of both devices, the adhesive patch monitor detected 96 arrhythmia events compared with 61 arrhythmia events by the Holter monitor (P < .001).</AbstractText>Over the total wear time of both devices, the adhesive patch monitor detected more events than the Holter monitor. Prolonged duration monitoring for detection of arrhythmia events using single-lead, less-obtrusive, adhesive-patch monitoring platforms could replace conventional Holter monitoring in patients referred for ambulatory ECG monitoring.</AbstractText>Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,291 | Organizational index mapping to identify focal sources during persistent atrial fibrillation. | Localized rotors have been implicated in the mechanism of persistent atrial fibrillation (AF). Although regions of highest dominant frequency (DF) on spectral analysis of the left atrium (LA) have been said to identify rotors, other mechanisms such as wavefront collisions will sporadically also generate an inconsistent distribution of high DF. We hypothesized that if drivers of AF were present, their distinctive spectral characteristics would result more from their temporal stability than their high frequency.</AbstractText>Ten patients with persistent AF underwent LA noncontact mapping. Following subtraction of far-field ventricular components, noncontact electrograms at 256 sites underwent fast Fourier transform. Mean absolute difference in DF between 5 sequential 7-second segments of AF was defined as the DF variability (DFV) at each site. Mean ratio of the DF and its harmonics to the total power of the spectrum was defined as the organizational index (OI). Mean DFV was significantly lower in organized areas (OI > 1 SD above mean) than at all sites (0.34 ± 0.04 vs 0.46 ± 0.04 Hz; P < 0.001). When organized areas were ablated during wide-area circumferential ablation, AF organized in remote regions (LA appendage ΔOI ablated vs unablated: +0.21 [0.06-0.41] vs -0.04 [-0.14-0.05]; P = 0.005).</AbstractText>At sites of organized activation, the activation frequency was also significantly more stable over time. This observation is consistent with the existence of focal sources, and inconsistent with a purely random activation pattern. Ablation of such regions is technically feasible, and was associated with organization of AF in remote atrial regions.</AbstractText>© 2014 Wiley Periodicals, Inc.</CopyrightInformation> |
12,292 | Stroke and thrombus formation appending to the MitraClip: what is the appropriate anticoagulation regimen? | Percutaneous mitral valve repair with the MitraClip system (Abbot Vascular, USA) is a promising technique for the non-surgical treatment of mitral regurgitation in special situations. The case is reported of a 72-year-old patient with history of atrial fibrillation and a severely impaired left ventricular function who underwent successful MitraClip implantation because of functional mitral regurgitation grade 3. The patient's post-interventional course was complicated three weeks later by a cardioembolic stroke due to thrombus formation on the MitraClip, despite receiving dual platelet therapy. |
12,293 | Takotsubo cardiomyopathy after minimally invasive mitral valve surgery: clinical case and review. | A sudden, unexpected, reversible, severe left ventricular dysfunction, mimicking an acute myocardial infarction without demonstrable obstructive coronary artery stenosis, was first recognized in Japan in 1990 and originally termed takotsubo cardiomyopathy. In 2006, the American Heart Association included takotsubo cardiomyopathy into its classification of primary acquired cardiomyopathy. The true incidence of takotsubo cardiomyopathy in the community is difficult to estimate. In fact, despite an increasing awareness, this syndrome has to date been under-recognized and misdiagnosed, mainly because of the transitory natures of its clinical and instrumental features. The study aim was to investigate the association between the occurrence of takotsubo cardiomyopathy and emotional or physical stressors, as described also in the setting of various surgical procedures. The case is also described of a 77-year-old woman who suffered a transient left ventricular dysfunction soon after cardiac surgery for valvular disease and epicardial cryoablation of atrial fibrillation. |
12,294 | Minimally invasive mitral valve reconstruction on the fibrillating heart for high-risk patients. | Mitral valve surgery after previous cardiac surgery is technically demanding and risky. In patients after coronary artery bypass grafting (CABG), mitral valve surgery is associated with a high risk of injury to the bypass graft with concomitant myocardial ischemia. An aortic valve prosthesis usually severely impairs access to the mitral valve, so that these patients are often denied surgery. Furthermore, patients with porcelain aorta may be inoperable.</AbstractText>A series of 10 patients undergoing minimally invasive mitral valve repair via a right-sided anterolateral minithoracotomy without aortic cross-clamping on the fibrillating heart was investigated. Four patients had an aortic valve prosthesis in situ, six patients had undergone previous CABG, and two patients presented with porcelain aorta.</AbstractText>Reconstruction was possible in nine patients. Cannulation was performed femorally in three patients, and via the axillary artery in seven patients. No fatalities were observed. One patient required rethoracotomy for bleeding and subsequently developed a right-sided pneumonia, and a second patient experienced lower-limb ischemia. The postoperative course of the other eight patients was uneventful. No patient presented with significant residual mitral insufficiency at control echocardiography.</AbstractText>Minimally invasive mitral valve reconstruction via a right-sided minithoracotomy represents an attractive surgical option in a high-risk reoperative setting.</AbstractText> |
12,295 | A randomized controlled trial of catheter ablation versus medical treatment of atrial fibrillation in heart failure (the CAMTAF trial). | Restoring sinus rhythm in patients with heart failure (HF) and atrial fibrillation (AF) may improve left ventricular (LV) function and HF symptoms. We sought to compare the effect of a catheter ablation strategy with that of a medical rate control strategy in patients with persistent AF and HF.</AbstractText>Patients with persistent AF, symptomatic HF, and LV ejection fraction <50% were randomized to catheter ablation or medical rate control. The primary end-point was the difference between groups in LV ejection fraction at 6 months. Baseline LV ejection fraction was 32±8% in the ablation group and 34±12% in the medical group. Twenty-six patients underwent catheter ablation, and 24 patients were rate controlled. Freedom from AF was achieved in 21/26 (81%) at 6 months off antiarrhythmic drugs. LV ejection fraction at 6 months in the ablation group was 40±12% compared with 31±13% in the rate control group (P=0.015). Ablation was associated with better peak oxygen consumption (22±6 versus 18±6 mL/kg per minute; P=0.014) and Minnesota living with HF questionnaire score (24±22 versus 47±22; P=0.001) compared with rate control.</AbstractText>Catheter ablation is effective in restoring sinus rhythm in selected patients with persistent AF and HF, and can improve LV function, functional capacity, and HF symptoms compared with rate control. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01411371.</AbstractText> |
12,296 | Quantitative assessment of the effects of therapeutic hypothermia on early repolarization in idiopathic ventricular fibrillation survivors: a 7-year cohort study. | The early repolarization (ER) pattern on ECG is associated with an increased risk of idiopathic ventricular fibrillation (ID-VF). Hypothermia is known to result in similar electrocardiographic changes. In this retrospective cohort study, we examine the impact of therapeutic hypothermia on ER in survivors of cardiac arrest attributed to ID-VF and draw comparisons with a control group who experienced coronary artery disease-related VF (CAD-VF).</AbstractText>All patients who had cardiac arrest and were treated with therapeutic hypothermia over a 7-year period were considered for inclusion in the study. Forty-three patients were identified with ID-VF or CAD-VF arrest. ECGs were obtained during cooling and again after rewarming. ECGs were digitized and assessed for the presence of ER by 2 independent observers. Cooling significantly increased the prevalence (74% during cooling versus 51% at baseline temperature; P=0.044) and mean amplitude (0.78±0.10 mV during cooling versus 0.56±0.09 mV at baseline temperature; P=0.038) of ER in the overall cohort. During cooling, ER was more common among survivors of ID-VF than of CAD-VF (100% versus 67%; P=0.043). ER magnitude was significantly greater among ID-VF survivors than CAD-VF survivors both during cooling (1.16±0.18 versus 0.70±0.11 mV; P=0.044) and at baseline temperature (1.02±0.21 versus 0.42±0.09 mV; P=0.005).</AbstractText>Hypothermia increases both the prevalence and magnitude of ER in cardiac arrest survivors. Despite the association of ER with ID-VF, therapeutic hypothermia only increases ER amplitude in CAD-VF survivors.</AbstractText> |
12,297 | Long-term arrhythmia-free survival in patients with severe left ventricular dysfunction and no inducible ventricular tachycardia after myocardial infarction. | A negative electrophysiology study (EPS) may delineate a subgroup of patients with severely impaired left ventricular ejection fraction (LVEF) whose care can be safely managed long-term without an implantable cardioverter-defibrillator.</AbstractText>Consecutive patients treated with primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction underwent early (median 4 days) LVEF assessment. Patients with LVEF ≤40% underwent EPS. A prophylactic implantable cardioverter-defibrillator was implanted for a positive (inducible monomorphic ventricular tachycardia) but not a negative (no inducible ventricular tachycardia or inducible ventricular fibrillation/flutter) EPS result. Patients who would have become eligible for a late primary prevention implantable cardioverter-defibrillator with LVEF ≤30% or ≤35% with New York Heart Association class II/III heart failure were included and analyzed according to EPS result. Patients with LVEF >40%, ineligible for EPS, were followed up as control subjects (n=1286). The primary end point was survival free of death or arrhythmia (resuscitated cardiac arrest or sustained ventricular tachycardia/ventricular fibrillation). EPS performed in 128 patients with LVEF ≤30% or with LVEF ≤35% and heart failure was negative in 63% (n=80) and positive in 37% (n=48). Implantable-cardioverter defibrillators were implanted in <0.1%, 4%, and 90% of control, EPS-negative, and EPS-positive patients, respectively. The distribution of time to death or arrhythmia was comparable in control patients and EPS-negative patients with LVEF ≤30% or with LVEF ≤35% and heart failure (P=0.738), who both differed significantly from EPS-positive patients (P<0.001). At 3 years, 91.8 ± 3.2%, 93.4 ± 1.0%, and 62.7 ± 7.5% of control, EPS-negative, and EPS-positive patients were free of death or arrhythmia, respectively.</AbstractText>Revascularized patients with ST-segment-elevation myocardial infarction with severely impaired left ventricular function but no inducible ventricular tachycardia have a favorable long-term prognosis without the protection of an implantable cardioverter-defibrillator.</AbstractText> |
12,298 | [Ambulatory Electrocardiogram In Stroke Patients At The University Hospital Of Brazzaville: 81 Cases]. | To assess the value of Holter ECG in the assessment of patients experiencing ischemic stroke.</AbstractText>This was a prospective descriptive study conducted in the Department of Neurology of the University Hospital Center in Brazzaville between June 2011 and June 2012.</AbstractText>There were 53 men (63.9%) and 30 women (36.1%), mean age 60.6 ± 12.7 years (range = 20 to 85 years). The average body mass index was of 26.9 ± 4.6 (range = 15.6 and 35.3). Patients were obese in 19 cases (22.8%), overweight in 16 cases (19.2%). Hypertension was found in 44 patients (53%), diabetes mellitus in 14 patients (16.8%), dyslipidemia, smoking, respectively, six (7.2%) and one case. The Holter ECG performed in 81 patients showed: sinus rhythm in 78 cases (96.3%), an average frequency of 79.1 ± 17.6 beats per minute (range = 50 to 163 years), atrial fibrillation in seven cases (8.6%), one case of atrial flutter, supraventricular tachycardia bursts in 14 cases (17.2%), supraventricular extrasystoles in 78 cases (96.3%), 65 cases (80.2%) with doublets and 27 cases (33.3%) with triplets. In 35 cases, there were more than 70 supraventricular extrasystoles per 24 hours. Ventricular extrasystoles were present in 59 cases (72.8%), including 24 cases of doublets (29.6%), 14 cases (17.2%) of bigeminy and three cases of nonsustained ventricular tachycardia. Breaks were significant in both cases. The study of HRV showed a 100.4 ± 45.8 to SDNN ms (range = 20 to 206 ms), 44 patients (54.3%) had impaired heart rate variability in 44 (54.3%).</AbstractText>The ischemic stroke is a serious life-threatening and functional. Administering a Holter ECG is essential to find a cardioembolic cause, allowing for the most appropriate treatment.</AbstractText>Le comitée de rédaction se réserve le droit de revoyer aux auteurs avant toute soumission à l'avis des lecteurs les manuscrits qui ne seraient pas conformes à ces modalités de présentation. En outre il leur conseille de sonserver un examplaire du manuscrit, des figures et des tableaux.</CopyrightInformation> |
12,299 | Is There a Role for Tissue Doppler Imaging in Infective Endocarditis? | An 87-year-old woman was admitted to our Cardiology Department with symptoms and signs of acute congestive heart failure and fever. She had a long history of hypertension and chronic atrial fibrillation. Transthoracic echocardiography showed a large (>10 mm) and mobile mitral valve vegetation, prolapsing into the left ventricular inflow tract, with severe mitral regurgitation due to a perforation in the posterior leaflet, in a mitral valve with fibro-calcific degeneration. Mitral regurgitation was hemodynamically significant and a moderate-to-severe pulmonary hypertension was observed. Tissue Doppler Imaging recorded at the level of the vegetation detected its incoherent motion and measured the peak antegrade velocity, which was found to be almost four times higher than that sampled at the lateral mitral annulus. Blood cultures were negative for both aerobic and anaerobic microbes. During hospitalization, the patient developed a sudden onset of left-side hemiplegia. Diffusion-weighted magnetic resonance imaging demonstrated multiple hyperintense lesions involving both hemispheres, suggestive of a cardioembolism. Diagnosis of fungal endocarditis was made and a treatment with fluconazole was started. Successive echocardiograms showed a decrease in the size and mobility of the mitral vegetation, and an increase in its echo intensity. However, in view of the systemic conditions severely affected, the patient was treated conservatively and died 3 months later. In our patient echocardiography played a key role for a better definition of the clinical course. In this context, Tissue Doppler Imaging might provide an adjunctive parameter for the prediction of embolic risk from endocardial vegetations: the peak antegrade velocity recorded at the level of the vegetation. However, before being adopted in clinical setting, this parameter should be validated by adequately powered prospective studies. |
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