A new biomarker that predicts ventricular arrhythmia in patients with ischemic dilated cardiomyopathy: Galectin-3

IntroductionVentricular arrhythmias are caused by scar tissue in patients with ischemic dilated cardiomyopathy. The gold standard imaging technique for detecting scar tissue is magnetic resonance imaging (MRI). However, MRI is not feasible for use as a screening test, and also cannot be used in patients who have received an implantable cardioverter-defibrillator (ICD). In this study, we aimed to assess the association between levels of galectin-3 (Gal-3), which is known to be secreted by scar tissue, and the history of ventricular arrhythmias in patients with ischemic dilated cardiomyopathy who received an ICD.MethodsNineteen healthy controls and 32 patients who had previously undergone VVI-ICD implantation due to ischemic dilated cardiomyopathy were enrolled in the study. Patients were divided into three groups: the first group including patients who had received no ICD therapies, the second including patients with arrhythmia requiring therapies with no arrhythmia storm, and the third including patients who had arrhythmia storm. We assessed the association between Gal-3 levels and the history of ventricular arrhythmias in these patients.ResultsGal-3 levels were significantly higher in the patient groups than in the control group (p<0.01). Gal-3 levels of patients with arrhythmias requiring ICD therapies were significantly higher than in patients with ICD not requiring therapies (p=0.02). They were also higher in patients with a history of arrhythmia storm than in patients without shocks (p=0.05). Receiver operating curve analysis showed with 84% sensitivity and 75% specificity that Gal-3 levels over 7 ng/ml indicated ventricular arrhythmia that required therapies.ConclusionGal-3 may be used to further improve risk stratification in patients with ischemic cardiomyopathy who are more prone to developing life-threatening arrhythmias.     

Advantages of a Subcutaneous Implantable Cardioverter‐Defibrillator in LAMP2 Hypertrophic Cardiomyopathy

Danon disease is a rare X‐linked lysosomal disease causing severe hypertrophic cardiomyopathy (LAMP2 cardiomyopathy) and an extremely poor prognosis in males, with several reported cases of sudden cardiac death despite the use of transvenous implantable cardioverter defibrillators (TV‐ICD). We describe a case in which a TV‐ICD was unable to defibrillate induced ventricular fibrillation (VF), but a wholly subcutaneous system (S‐ICD) was successful in terminating induced VF and spontaneous ventricular tachycardia. These findings have relevance to the selection of device therapy in the management of these individuals and a wider group of young patients with severe hypertrophic cardiomyopathy.     

High risk of ventricular arrhythmias in patients with nonischemic dilated cardiomyopathy presenting with syncope

It is not entirely clear whether the presentation of syncope in patients with nonischemic dilated cardiomyopathy (NIDC) is an ominous prognostic indicator, because randomized controlled implantable cardioverter-defibrillator (ICD) trials generally exclude such patients. This study compared 108 consecutive patients with NIDC presenting with syncope with 71 consecutive patients with NIDC who presented with sustained ventricular arrhythmias, with regard to freedom from any ventricular arrhythmias or life-threatening arrhythmias and all-cause mortality. There was no significant difference between the groups in the 3 outcomes during the follow-up of 43.5 +/- 32.1 months. Male gender and ICD therapy predicted increased risk for any ventricular arrhythmias. A reduced left ventricular ejection fraction and increased age were predictive of increased mortality. In conclusion, patients with NIDC presenting with syncope are a high-risk group, with event rates similar to patients with NIDC presenting with sustained arrhythmias, and should be considered for ICD therapy.     

Indications for implantable cardioverter defibrillator therapy

The implantable cardioverter defibrillator (ICD) is now an integral therapy for cardiac patient care. More than 20 years have passed since the first ICD implant. Sudden cardiac death from arrhythmia (ventricular tachycardia and fibrillation) has been significantly decreased because of the use of ICD therapy. Primary treatment trials have shown ICD therapy to be superior to drug therapy. Most of these trials compared ICD therapy with amiodarone or sotalol. Prevention trials have also been completed. Patients with nonsustained ventricular tachycardia, low left ventricular ejection fraction, and coronary artery disease were evaluated with electrophysiology studies. Patients with inducible ventricular arrhythmias were treated with ICD or drug suppression therapy. ICD therapy was superior to drug therapy for prevention of fatal arrhythmias. Ongoing trials include evaluation of ICD therapy for patients with high-risk substrates: congestive heart failure, dilated cardiomyopathy, hypertrophic cardiomyopathy, and repolarization syndromes. Factors such as medication inefficacy/side effects, transvenous ICD implantation and overwhelming mortality benefits have expanded ICD usage beyond the original restrictive guidelines.     

T Wave Pacing Inducing Electrical Storm and Multiple Shocks in an ICD-Recipient: A Novel Complication of the Automatic Gain Control Function

Implantable cardioverter-defibrillator (ICD) is highly effective in treating life-threatening ventricular arrhythmias, but it can also have proarrhythmic effect in some cases. We report the case of a 72 years old patient with an ischemic cardiomyopathy in whom an ICD was implanted for a poorly tolerated ventricular tachycardia (Profiles MD—Ventritex). Forty-eight hours after implantation, the patient suddenly received 15 successive shocks. ECG tracings and intracardiac EGM showed the presence of several VT episodes, all induced by the antibradycardia pacing of the ICD: the automatic gain control function of the device failed to detect ventricular premature beats in this patient, leading to a bradycardia pacing falling on the T wave and inducing multiple VTs and shocks.     

Kommentar zu den „ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death – executive summary“

The purpose of this document is to translate and to comment on the previously published“ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death”. The aim is to update the recommendations for clinical practice in Germany. We address the diagnostic procedures (e.g. ECG, imaging, electrophysiological studies etc.) and therapeutic options (e.g. medical treatment, catheter ablation, implantable cardioverter defibrillator – ICD etc.). Special emphasis was put on management of acute ventricular arrhythmias and on the different treatment modalities for various conditions (e.g. ischemic cardiomyopathy, valvular heart disease, congenital heart disease, non-ischemic cardiomyopathies, congestive heart failure, genetic arrhythmia syndromes etc.). Comments are given in each chapter, including the ongoing debate about ICD indications in primary prophylaxis.     

延迟增强心肌磁共振定量分析对缺血性心肌病患者室性心律失常预测价值

目的探索延迟增强心脏磁共振成像(DE-CMR)定量分析对缺血性心肌病患者发生室性心律失常的预测价值。方法 41例缺血性心肌病伴有左心室射血分数≤35%的患者在植入心脏转复除颤器(ICD)前进行DE-CMR检查,对心肌延迟增强定量分析,并对ICD定期程控记录室性心律失常发生情况。结果在平均(441±209)d随访中,12例(29%)患者ICD)记录到自发或治疗终止的持续性室性心动过速或心室颤动。发生室性心律失常患者的增强心肌质量及其占左心室心肌质量百分比均显著高于无室性心律失常组[(60.1±24.4)g比(40.9±20.1)g,P=0.01)及(51.8%±20.0%)比(37.8%±15.2%),P=0.02]。受试者工作特征曲线(ROC)分析显示增强心肌质量或其百分比对室性心律失常预测价值高于射血分数。在多因素分析中,增强心肌质量(HR 1.54/10 g;95%CI1.06～2.45,P=0.02)或其百分比(HR 1.65/10%;95%CI 1.05～2.58;P=0.03)是惟一的发生室性心律失常预测因子。结论 DE-CMR定量分析是预测缺血性心肌病患者发生室性心律失常的独立危险因子。     

Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review

According to the current guidelines, patients with ischaemic cardiomyopathy (ICM) or non-ischaemic cardiomyopathy (NICM) at risk for sudden cardiac death should undergo implantation of an implantable cardioverter-defibrillator (ICD). Although ICDs effectively terminate ventricular arrhythmias, the arrhythmogenic substrate remains unchanged or may progress over time, resulting in recurrent ICD shocks. Defibrillator shocks increase mortality and worsen quality of life. Evidence from two prospective randomized trials on outcome in patients with ischaemic heart disease undergoing catheter ablation for ventricular tachycardia (VT) suggests that ablation prevents recurrence of VT and decreases the number of ICD shocks. This review will highlight the recent progress made in the ablative treatment of VT in patients with ICM and NICM.     

Troponin-I elevation in a young man with arrhythmogenic right ventricular dysplasia/cardiomyopathy

Ventricular arrhythmias occur frequently in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) as well as those with ischemic heart disease. We present the case of a 29-year-old man with ARVD/C and multiple episodes of symptomatic ventricular tachycardia terminated by implantable cardioverter defibrillator (ICD) discharges. Phasic elevation of troponin-I prompted repeated coronary angiograms, all of which were normal. The patient was successfully treated with radiofrequency ablation. This case illustrates that ARVD/C may result in elevated cardiac enzymes in the absence of coronary artery disease.     

When an ICD is not the answer... hypothyroidism-induced cardiomyopathy and torsades de pointes

Introduction: An increasing number of patients with left ventricular (LV) dysfunction are referred for placement of an implantable cardioverter‐defibrillator (ICD). Case Report: A 78‐year‐old female with fatigue, palpitations, and presyncope was referred for consideration of an ICD because of a cardiomyopathy and nonsustained ventricular tachycardia (VT). Her evaluation revealed severe hypothyroidism, marked QT prolongation, and episodes of torsades de pointes. With levothyroxine therapy, her ventricular arrhythmias rapidly abated, with subsequent normalization of LV function and the QT interval. Conclusions: This report highlights the critical importance of detecting hypothyroidism as an unusual cause for reversible cardiomyopathy and ventricular arrhythmias.     

The Timing of Implantable Cardioverter-Defibrillator Implantation in Patients with Heart Failure

Patients who survive a myocardial infarction (MI) are at increased risk of sudden death due to fatal ventricular arrhythmias. Implantable cardioverter-defibrillators (ICDs) reduce mortality in appropriately selected patients with heart failure and left ventricular dysfunction, regardless of etiology. Post hoc analyses from landmark trials have evaluated the effect of time (both since MI and duration of nonischemic cardiomyopathy) before ICD implantation on the efficacy of ICD therapy. Time remains a clinically important variable in the decision of if and when to implant an ICD. Future trials should focus on invasive and/or noninvasive risk stratification of patients with ischemic and nonischemic cardiomyopathy for better identification of those who would benefit from early ICD implantation, and those in whom a watch and wait approach is appropriate.     

致心律失常性右室发育不良或心肌病15例的临床特点及疗效

目的 探讨致心律失常性右室发育不良或心肌病(ARVD/C)的临床特点及分析疗效。方法 分析2000～2007年诊断为ARVD/C 15例入院病例资料,对其临床特点作统计分析,并探讨治疗方法及疗效。结果 在ARVD/C 15例病例中(7男),年龄为13～61(31±12)岁,首发症状年龄为10～51(28±11)岁;3例有家族史;6例(40%)有晕厥发作史;5例(33%)患者仅有心悸症状;1例常规心电图检查中发现Epsilon波,见于右侧胸导联V2～3,伴有T波倒置;13例(87%)超声心动图结果异常,主要为RV扩大;4例行心脏磁共振（MRI）检查:见右室壁脂肪信号2例,右室壁变薄3例,右心室扩大3例;有症状的室性心律失常患者接受胺碘酮、β阻滞剂或采用其他抗心律失常药物治疗,但47%的患者(7/15)应用抗心律失常药物治疗无效,3例患者接受射频消融治疗,其中有1例患者出现室性心动过速复发。4例患者植入植入式心脏自动复律除颤器 (ICD),其中1例因多次自动除颤,电池耗竭,而更换ICD。结论 ARVD/C以室性心律失常为主要表现,诊断依靠家族史、晕厥发作史、ECG、超声心动图、MRI。抗心律失常药物的疗效较差,射频消融或植入ICD可治疗致命性心律失常,减少猝死的发生。     

Arrhythmia Risk Stratification with Regard to Prophylactic Implantable Defibrillator Therapy in Patients with Dilated Cardiomyopathy

To date, generally accepted indications for prophylactic defibrillator implantation in patients with dilated cardiomyopathy do not exist. Recently, the Marburg Cardiomyopathy Study (MACAS) revealed left ventricular ejection fraction to be the only significant arrhythmia risk predictor in a relatively large patient population with dilated cardiomyopathy. Meanwhile, the preliminary results of two prospective randomized trials evaluating prophylactic defibrillator therapy in dilated cardiomyopathy have been reported. The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study (DEFINITE) randomized 458 patients with a history of symptomatic heart failure, a left ventricular ejection fraction < or = 35% and arrhythmias on Holter to an ICD versus no ICD. As a result, ICD therapy was associated with a significant reduction of arrhythmic deaths, which failed to result in a significant decrease in total mortality due to an insufficient number of patients in DEFINITE. The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) was a three-arm study comparing placebo to amiodarone to prophylactic ICD therapy in a total of 2,521 patients with ischemic cardiomyopathy (51%) or nonischemic dilated cardiomyopathy (49%). All patients in SCD-HeFT had a left ventricular ejection fraction inverted exclamation mark U 35% despite optimized medical heart failure therapy. SCD-HeFT showed a significant reduction of total mortality in the ICD group, whereas amiodarone did not improve survival.     

Non-invasive sudden death risk stratification.

Most sudden cardiac deaths are caused by fatal ventricular arrhythmias (ventricular tachycardia [VT] and fibrillation) in patients with and without known structural heart diseases. Given the large number of patients potentially at risk for developing ventricular arrhythmias, any strategy for treating them prophylactically requires efficient and effective risk stratification. Both non-invasive and invasive testing may be used for prognostic evaluation of patients with heart diseases. The optimal way to use them in the risk stratification for sudden cardiac death will depend in part on the goals of screening. At present risk markers perform better at identifying low-risk patients who may not need an implantable cardioverter-defibrillator (ICD), because all tests have a high negative predictive accuracy. In our opinion an electrophysiological test should not be performed and an ICD should not be implanted in post-myocardial infarction patients with moderate left ventricular dysfunction (left ventricular ejection fraction 30-40%) with a preserved autonomic balance and without non-sustained VT. In MADIT II-like patients electrophysiological testing does not seem necessary and an ICD could not be implanted only in patients with a negative T-wave alternans test. Most of the data available refer to patients with ischemic cardiomyopathy but the preliminary data on T-wave alternans suggest its usefulness in patients with non-ischemic cardiomyopathy too, although a large definitive study has not yet been completed in this important population.     

Equivalent arrhythmic risk in patients recently diagnosed with dilated cardiomyopathy compared with patients diagnosed for 9 months or more.

BACKGROUND: The Centers for Medicare and Medicaid Services (CMS) recently expanded coverage for implantable cardioverter-defibrillators (ICDs) in patients with left ventricular ejection fraction < or =35% and nonischemic dilated cardiomyopathy for > or =9 months. To investigate the ramifications of these criteria, the ICD registry from Tufts-New England Medical Center was analyzed for arrhythmic events and death in patients with newly diagnosed (<9 months) vs late-diagnosed (> or =9 months) nonischemic dilated cardiomyopathy. OBJECTIVES: The purpose of this study was to analyze the arrhythmic risk in patients with recent vs late diagnosis of nonischemic dilated cardiomyopathy. METHODS: One hundred thirty-one patients with nonischemic dilated cardiomyopathy were divided into two cohorts (<9 or > or =9 months of symptoms) and analyzed for any occurrence of treated ventricular arrhythmia, potentially lethal arrhythmias defined as ventricular flutter rates > or =230 bpm, and ventricular fibrillation. Patients with documented sustained ventricular tachycardias (included in prior CMS coverage) were excluded. RESULTS: In the study group, the mean age was 58.1 +/- 15 years and ejection fraction 20.6% +/- 8%. In a follow-up period of 25.3 +/- 24 months, the 52 patients with a recent diagnosis (1.4 +/- 2 months) had no difference in the occurrence of ventricular arrhythmias (P = .49) and malignant ventricular arrhythmias (P = .16) compared with the 79 patients diagnosed > or =9 months (mean 58.1 +/- 39 months). CONCLUSION: Patients with nonischemic dilated cardiomyopathy experienced equivalent occurrences of treated and potentially lethal arrhythmias irrespective of diagnosis duration. These findings suggest that the 9-month time qualifier used in the CMS guidelines for ICD reimbursement may not reliably discriminate patients at high risk for sudden cardiac death in this selected population.     

His bundle ablation for supraventricular arrhythmias to avoid spurious shocks of an implanted defibrillator

Atrial fibrillation with fast ventricular response remains a matter of concern in patients treated with an implantable cardioverter defibrillator (ICD). A patient with dilated cardiomyopathy, suffering from atrial arrhythmias and recurrent cardiac arrest due to both ventricular tachycardia and ventricular fibrillation, is presented. Ablation of the AV node by means of low-energy direct-current shocks with subsequent pacemaker implantation was performed before ICD implantation. The patient received shocks after four months, when he had recurrence of AV conduction with a slow ventricular rate. Pacemaker interaction was excluded, and no short ventricular arrhythmias were observed. During electrophysiologic study after electrical conversion of atrial fibrillation, persistent second degree heart block was documented, giving further evidence that atrial arrhythmias were not responsible for the shocks. The patient's functional status remains good after more than 18 months of follow-up.     

扩张型心肌病的治疗进展

扩张型心肌病(DCM)的基本治疗包括抗心力衰竭、心律失常及预防血栓栓塞等并发症。β-受体阻滞剂、血管紧张素转换酶抑制剂与血管紧张素受体拮抗剂及醛固酮受体拮抗剂可降低DCM心力衰竭的死亡率。胺碘酮对室性心律失常的治疗是安全有效的,埋藏式心脏复律除颤器(ICD)则可减少猝死,但ICD是否可在DCM的一级预防中应用尚存争议。心脏再同步治疗为部分心力衰竭患者提供了新的治疗方法。外科治疗主要适用于难以治疗的、晚期的DCM心力衰竭患者。他汀类药物及已酮可可碱、免疫球蛋白的使用可短期改善DCM患者的心功能。     

Implantable cardioverter-defibrillators in children

BACKGROUND: Implantable cardioverter-defibrillators (ICD) have been increasingly used in adult patients for the prevention of sudden cardiac death (SCD). The usefulness and feasibility of ICD implantation in children have been less well established. AIM: To analyse indications, results and safety of ICD therapy in children. METHODS: ICDs were implanted in seven children, aged from 6 to 17 years. All patients underwent cardiological evaluation which included analysis of medical history, physical examination, chest X-ray, standard ECG, 24-hour Holter ECG monitoring and echocardiography. RESULTS: In five children devices were implanted due to aborted sudden death (ventricular fibrillation) whereas in the remaining two - as a primary prevention of SCD. Three children had hypertrophic cardiomyopathy, one - dilated cardiomyopathy, one - mitral valve prolapse and QT prolongation, one - congenital long QT syndrome and the remaining patient - idiopathic ventricular tachycardia. Single-chamber devices were implanted in six children, and dual-chamber system - in one patient. In all patients endocardial leads were implanted and ICD pocket was formed under the greater pectoral muscle. During follow-up ranging between four months to 5.4 years, four children developed ventricular fibrillation or ventricular tachycardia which were terminated by appropriate ICD discharges. CONCLUSIONS: 1. ICD implantation in children is effective in the prevention of SCD. 2. In our population, the most frequent indications for device implantation were life-threatening ventricular arrhythmias occurring in patients with cardiomyopathy. 3. Cardiac arrest due to ventricular fibrillation may occur in children without a history of aborted SCD. 4. ICD implantation in children is feasible and safe.     

The use of implantable cardioverter-defibrillators in patients at high risk of sudden cardiac death

We have reviewed literature on contemporary views on sudden cardiac death (SCD), detection of category of patients belonging to the group with high risk of SCD, and methods of SCD prevention. Randomized studies on assessment of efficacy of implantable cardioverter-defibrillators (ICD) for primary and secondary prevention of SCD have been reviewed in detail as well. We also present experience with clinical management of patients with ICD in the Main Military Clinical Hospital named after N.N.Burdenko. Primary implantations were carried out in 42 patients (5 women) aged 52.7+/-11.9 (19-80) years for secondary (40 patients) or primary (2 patients) SCD prevention. In most patients etiological factor of life threatening ventricular arrhythmias was ischemic heart disease and indications on myocardial infarction in anamnesis (28 patients). In remaining 14 patients we diagnosed right ventricular arrhythmogenic dysplasia (6 patients), dilated cardiomyopathy (3 patients), hypertrophic cardiomyopathy (2 patients), long QT syndrome (2 patients), and the Brugada syndrome (1 patient). During follow-up (from 2 to 48 months, mean 23.7+/-15.4 months) 2 patients died in 5 and 11 months after ICD implantation. In this period ICD discharges were registered in 27 patients (64%). Only in 2 of them (5%) at subsequent testing of the device the therapy was considered unjustified.     

Ventricular Arrhythmias in the North American Multidisciplinary Study of ARVC : Predictors,Characteristics, and Treatment

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is associated with sudden cardiac death. However, the selection of patients for implanted cardioverter-defibrillators (ICDs), as well as programming of the ICD, is unclear.

Objectives

The objective of this study was to identify predictors, characteristics, and treatment of ventricular arrhythmias in patients with ARVC.

Methods

The Multidisciplinary Study of Right Ventricular Cardiomyopathy established the North American ARVC Registry and enrolled patients with a diagnosis of ARVC. Patients were followed prospectively.

Results

Of 137 patients enrolled, 108 received ICDs. Forty-eight patients had 502 sustained episodes of ventricular arrhythmias, including 489 that were monomorphic and 13 that were polymorphic. In the patients with ICDs, independent predictors of ventricular arrhythmias in follow-up included spontaneous sustained ventricular arrhythmias before ICD implantation and T-wave inversions inferiorly. The only independent predictor for life-threatening arrhythmias, defined as sustained ventricular tachycardia (VT) ≥240 beats/min or ventricular fibrillation, was a younger age at enrollment. Anti-tachycardia pacing (ATP), independent of the cycle length of the VT, was successful in terminating 92% of VT episodes.

Conclusions

In the North American ARVC Registry, the majority of ventricular arrhythmias in follow-up are monomorphic. Risk factors for ventricular arrhythmias were spontaneous ventricular arrhythmias before enrollment and a younger age at ICD implantation. ATP is highly successful in terminating VT, and all ICDs should be programmed for ATP, even for rapid VT.