6例埋藏式心脏转复除颤器频繁电击分析与处理

目的分析6例埋藏式心脏转复除颤器(ICD)患者术后频繁电击的临床特点。方法回顾2008年至今42例ICD植入患者中6例术后频繁电击的临床资料。结果 6例发生频繁电击(发生率14.3%),随访8~38个月,死亡1例。1例CRT-D患者半年内发生6次ICD电风暴,多为反复发生室性心动过速(VT)、快VT(FVT),抗心动过速起搏(ATP)无效升级为电击治疗或者ATP诱发FVT、心室颤动(VF)而行电击治疗,首次电风暴9个月后死于顽固心力衰竭;1例左上腔植入单腔ICD患者出现3次血流动力学稳定的VT事件频率进入VF诊断区直接电击治疗6次且无效;1例单腔ICD患者因T波过感知致11次误放电;1例双腔ICD患者出现3次血流动力学稳定的VT事件,ATP失败后电击治疗6次且无效,此3例均经优化程控后无电击事件。1例CRT-D患者因右室电极脱位至三尖瓣环处致P、R双计数误识别为3次VF并予电击,经再次手术复位后无类似事件。1例CRT-D患者极短期内因2次VF事件及1次VT事件,10阵ATP无效而先后3次电击治疗,优化药物及程控后无电击事件。结论ICD术后频繁电击病因及诱因治疗是预防发生和及时终止的基础,优化药物及程控治疗可降低对电击治疗的需求及误放电的发生,必要时手术调整或导管消融。     

埋藏式心脏转复除颤器患者的随访

目的报道7例埋藏式心脏转复除颤器(ICD)治疗恶性室性心律失常的情况。方法对6例单腔ICD及1例双腔ICD植入者进行随访,通过ICD程控仪调出储存的资料,了解ICD对恶性心律失常的治疗情况,并对其工作情况进行分析。结果随访5～44个月,平均23.7个月,ICD共检测到持续性室性心动过速(VT)2 129次,心室颤动(VF)6次。采用抗心动过速起搏(ATP)治疗VT的成功率为91.9%,ATP未能终止的VT经低能量转复(CV)治疗95.3%转为窦性心律,少数VT经治疗后加速为VF。高能量除颤(DF)终止VF的成功率为100%。4例12次误将室上性心动过速误判断为室性事件而启动治疗,其中2次心房颤动,10次窦性心动过速,经调整VT的识别参数及联合使用抗心律失常药物后未再发生类似情况。2例随访期间出现晕厥,ICD存储的信息显示发生了VF并复律成功。2例出现焦虑症,经心理治疗改善。结论术后严密随访,及时调整工作参数,同时关注患者的心理健康并给予针对性的心理支持和治疗,对提高ICD的治疗效果至关重要。     

植入型心律转复除颤器不适当治疗的原因分析及处理

目的 分析植入型心律转复除颤器(ICD)误诊断和误放电治疗的原因,寻找解决方法 .方法 34例住院病人,男性24例,女性10例,平均年龄(62.54±11.17)岁.植入单腔ICD(VVI)21例,双腔ICD(DDDR)3例,三腔ICD(CRT-D)10例,平均随访(20.72±16.98)个月.结果 (1)ICD的误诊断和误放电治疗6例(占17.6%),其中单腔ICD 3例,三腔ICD 3例.(2)原因:1例(单腔ICD)对噪音误识别;4例患者是对心房颤动(AF)伴快速心室率的误识别,由于AF的心室率达到心室颤动(VF)检测区的标准,将其识别为VF.1例(V350型,ST.Jude公司)CR-D患者因室上性心动过速(SVT)误电击7次,原因是ICD能正确识别SVT,但出厂设置了对SVT的最长诊断时间为60 s,SVT持续60 s后不消失,ICD自动按室性心动过速设置程序进行治疗,行3阵ATP治疗未转复继续电转复.(3)2例患者在VF区设立了快速室性心动过速(FVT)区,4次AF的心室率达到FVT检测区频率,经1阵抗心动过速起搏(ATP)治疗后转复.(4)共误放电40次.单腔ICD患者14次,三腔ICD患者26次.6例患者均发生在短时间内连续电击事件,1例患者曾在3 h内发生7次电击事件.结论 AF伴快速心室率(达到VF区的频率)是各种ICD误识别的主要原因,因此控制AF的心室率是减少ICD不适当治疗的基础.过多的电击治疗会给患者很大的痛苦和恐惧,建议加强药物治疗,必要时行射频消融治疗.     

植入埋藏式心脏转复除颤器的临床应用与随访

目的报道13例埋藏式心脏转复除颤器(implantable cardioverter defibrillator,ICD)的临床应用与随访结果。方法对置入10例单腔ICD及3例双腔ICD患者进行电话询问和门诊随访,通过心电图、动态心电图及ICD存储的资料,对患者病情和ICD工作情况进行分析。结果 13例患者共发作持续性室性心动过速/心室颤动(ventricular tachycardia/ventricular fibrillation,VT/VF)38次(持续性VT 36次,VF 2次),其中37次治疗成功,1次失败。非持续性VT 121次,发作均自行停止。36次持续性VT中33次经抗心动过速起搏(antitachycardia pacing,ATP)终止,2次经低能量复律(CV)终止,1次VT治疗过程中加速为VF,由高能量除颤(DF)终止。1例共2次阵发性心房颤动心室率超过设置的VT频率,ICD发生误识别,给予ATP治疗。1例术后3个月出现心律失常"电风暴"。共有3例术后因VT发作频繁而服用胺碘酮和(或)美托洛尔,并根据心律失常发作情况调整用药剂量。结论 ICD植入后应加强随访,及时调整工作参数,同时给予患者心理治疗、对提高ICD的治疗效果非常重要。     

植入带有家庭监测系统的心律转复除颤器20例临床随访及评价

目的 对我院20例植入带有家庭监测系统的心律转复除颤器(ICD)患者进行门诊及家庭监测系统随访.探讨家庭监测系统对植入ICD患者电极导线及脉冲发生器安全性评价及对包括房性心律失常、恶性室性心律失常在内的临床事件的早期发现及干预效果.方法 收集20例2010年6月至2011年11月在我院植入带有家庭监测系统的ICD患者的临床特征、植入信息及通过家庭监测网站系统和门诊常规随访结果,将随访结果进行回顾性总结分析.结果 20例患者随访117 ～ 644(332.90±175.25)d,在随访过程中,累计有6例患者有室性心律失常事件发生,其中有5例患者成功接受ICD,占全部患者的25％.1例患者因快速心房颤动(房颤)被误识别为心室颤动(VF)而进行电除颤.5例成功接受ICD治疗的患者中有1例患者曾因房性心动过速(房速)误识别为室性心动过速(VT)而进行电除颤,误识别及误放电的发生率为9.1％.除去误识别及误放电外,所有患者共发作室上性心动过速(SVT) 238次,VT/VF 20次,其中VT 7次(35％),VF 13次(65％).VT发作均由抗心动过速起搏治疗(ATP)终止,共发放26阵ATP,成功转复7次,ATP转复率27％,VT治疗成功率100％.VF导致充电开始13次,其中10次在ICD结束充电前自行终止,3次在放电治疗后成功转复,ICD治疗成功率100％.20例患者中无1例死亡.结论 通过家庭监测网络系统,不仅可以对ICD患者电极导线及脉冲发生器的正常运转进行有效监控,还可以在患者出现自觉症状前尽早发现患者潜在的恶性心律失常事件和心功能的恶化,并给予及时处理,以避免ICD事件的发生和治疗,从而给患者带来更大的获益.     

植入型心律转复除颤器在致心律失常性右心室心肌病患者中的应用

目的 总结阜外心血管病医院应用植入型心律转复除颤器(ICD)治疗致心律失常性右心室心肌病(ARVC)的经验.方法 入选我院2004年3月至2012年3月确诊并植入ICD的ARVC患者,收集临床资料,进行常规电话及门诊随诊.结果 共18例患者[男12例,女6例,平均年龄(46.4±13.8)岁]入选,平均随访(46.6±30.5)个月,有6例患者出现了111次室性心动过速(VT)/心室颤动(VF)事件,其中仅1次VF事件,其余均为VT事件,其中3例患者术后共出现了7次电风暴.ICD治疗组中的C反应蛋白(CRP)明显高于ICD未治疗组.111次VT/VF事件中,12次经电除颤终止心动过速,其余均通过抗心动过速起搏(ATP)终止了心动过速.结论 ARVC患者ICD植入后的VT/VF事件以VT为主,多数可经ATP终止;出现电风暴的ARVC患者易反复发作恶性心律失常;CRP可能对ICD治疗具有预测价值.     

植入型心律转复除颤器治疗室性快速心律失常的临床应用

目的探讨植入型心律转复除颤器（ICD）对室性快速心律失常的治疗效果以及随访过程中所遇到的问题。方法48例植入ICD患者（其中8例为双腔ICD）,根据患者室性心动过速（VT）/心室颤动（VF）发作时的频率及对血流动力学的影响确定方法和参数,并对植入ICD患者定期随访。结果48例患者顺利植入ICD,无并发症,在随访1～38个月中,患者共发作VT/VF 1 025次（VT764次,占74.5%;VF 261次,占25.5%）,其中1 009次（98.4%）治疗成功,16次在ICD充电结束前自行终止。764次VT中,658次（86.1%）经抗心动过速起搏（ATP）终止,106次（13.9%）经低能量复律（CV）终止。261次VF中,经高能量除颤（DF）均终止。6例患者发生误放电19次,8例双腔ICD患者无误放电。结论ICD的疗效是确定的。但单腔ICD常会发生误识别、误放电,随访和及时调整参数可避免或减少此类情况发生。双腔ICD提高了对室上性心律失常的识别能力,从而减少误发电。同时应合理应用抗心律失常药物,高度重视ICD患者的心理治疗。     

植入型心律转复除颤器临床应用

目的　观察 5例恶性室性心律失常患者植入型心律转复除颤器 (ICD)植入术及临床随访情况。方法　 5例因反复发作有血流动力学障碍的室性心动过速 /心室颤动 (VT/ VF)均顺利植入 ICD(其中双腔 ICD2例 ) ,随访 6～ 2 4个月 ,观察患者临床疗效及 ICD工作情况。结果　 5例患者无 1例死亡。随访期间共出现 VT/ VF事件 30 4次 ,ICD识别并治疗的 VT/ VF事件 71次 ,VT 6 5次 ,占 91.5 % ,VF 6次 ,占 8.5 % ,抗心动过速起搏 (ATP)终止 5 5次 ,占77.5 % ,心律转复 (CV)终止 16次 ,占 2 2 .5 % ,VF经除颤 (DF)全部一次成功。结论　 ICD的治疗效果肯定 ,需加强随访 ,及时修改参数 ,同时应加强药物的辅助治疗 ,如 β-受体阻断剂 ,胺碘酮等 ,积极改善心功能。     

植入型心律转复除颤器治疗34例随访

目的:对我院37例安装植入型心律转复除颤器患者中34例长期随访(3例失访)。方法:将随访结果进行回顾性总结分析。结果:随访时间4～69个月,平均(24.7±18)个月。29例成功接受植入型心脏复律除颤器(ICD)治疗,占全部患者的85.3%。共发作恶性室性心律失常事件587次,其中313次为非持续性,均自行终止。接受ICD治疗的274次中室性心动过速(VT)238次,占86.9%。心室颤动(VF)36次,占13.1%。VT由抗心动过速起搏(ATP)终止212次,由低能量(2～15J)转复终止23次。有3次VT在ATP治疗时转为VF,由高能量除颤(DF)终止。VF经高能量除颤36次,全部一次成功。5例患者因房性心动过速(房速)或心房颤动(房颤)被误识别为VT而发放电击。34例中有3例死亡,1例死于急性心肌梗死,1例死于心力衰竭,1例死因不明。结论:ICD可以有效的终止VT、VF,是防治心源性猝死的有效治疗手段。     

置入埋藏式心律转复除颤器的长期随访

目的报道8例埋藏式心脏转复除颤器（1CO）治疗恶性室性心律失常的疗效及随访结果。方法对置入ICD的8例患者进行电话询问和门诊随访,通过常规心电图、动态心电图及ICD存储的资料,对患者病情和ICDT作情况进行分析。结果8台ICD共检出心律失常事件263次,其中202次为短阵非持续性室性心动过速（VT）,自行终止,61次为持续性VT／（室颤）VF,32次为抗心动过速（ATP）终止,21次为低能量电击终止,8次为高能量电击终止,再发恶性室性心律失常全部经ICD成功转复为窦性心率,有效率100％。误放电治疗8次。误放电原因：阵发性心房颤动心室率超过设置的VT频率,ICD发生误识别。结论ICD治疗恶性室性心律失常效果肯定,但应加强随访,警惕误放电。     

Implanted defibrillators and primary prevention of sudden cardiac death: where are we today?

Implanted defibrillators have become a mainstream therapy for the prevention of sudden cardiac death (SCD) from ventricular tachyarrhythmias in patients with chronic coronary artery disease. A decade of studies has confirmed the superiority of ICDs over antiarrhythmic drug therapy in prolonging the life of patients with a prior history of sustained VT or VF. Furthermore, recent studies have examined the role of ICD therapy in the primary prophylaxis against sudden death in patients considered at high risk for ventricular tachyarrhythmias. These studies have revealed that in selected patients with the substrate of chronic coronary artery disease and a ventricular scar, ICDs lead to important relative and absolute reductions in mortality in such patients without a prior history of VT or VF. Clinicians caring for patients with chronic coronary artery disease (CAD) and severe LV dysfunction, who are at a risk of sudden cardiac death, need to carefully consider this information when managing this patient population.     

Implantable defibrillator event rates in patients with idiopathic dilated cardiomyopathy, nonsustained ventricular tachycardia on Holter and a left ventricular ejection fraction below 30%

OBJECTIVES: This study investigated the incidence of appropriate implantable cardioverter defibrillator (ICD) interventions for ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with idiopathic dilated cardiomyopathy (IDC) and nonsustained VT in the presence of a left ventricular ejection fraction below 30%, versus in patients with syncope and patients with a history of VT or VF. BACKGROUND: To date, only limited information is available about the prophylactic use of ICDs in patients with IDC. METHODS: From January 1993 to July 2000, 101 patients with IDC underwent implantation of ICDs with electrogram storage capability at our institution. Patients were placed into one of three groups according to their clinical presentation: asymptomatic or mildly symptomatic nonsustained VT in the presence of a left ventricular ejection fraction < or = 30% (49 patients, prophylactic group), unexplained syncope or near syncope (26 patients, syncope group) and a history of sustained VT or VF (26 patients, VT/VF group). RESULTS: During 36 +/- 22 months follow-up, 18 of 49 patients (37%) in the prophylactic group received appropriate shocks for VT or VF, compared with 8 of 26 patients (31%) in the syncope group and with 9 of 26 patients (35%) of the VT/VF group. Multivariate Cox analysis of baseline clinical variables identified left ventricular ejection fraction, atrial fibrillation and a history of sustained VT or VF as predictors for appropriate ICD interventions during follow-up. CONCLUSIONS: Patients with IDC and prophylactic ICD implantation for nonsustained VT in the presence of a left ventricular ejection fraction < or = 30% had an incidence of appropriate ICD interventions similar to that of patients with a history of syncope or sustained VT or VF. These findings indicate that ICDs may have a role in not only secondary but also primary prevention of sudden death in IDC.     

The effect of spironolactone on ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators

Background- Previous studies have suggested that aldosterone blockade can reduce the incidence of ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with heart failure. The SPIronolactone to Reduce ICD Therapy (SPIRIT) trial was designed to test the hypothesis that spironolactone reduces the incidence of VT/VF in patients with implantable cardioverter-defibrillators (ICDs) who are at moderately high risk for recurrent VT/VF. Methods and Results- Ninety patients who had ICDs who were at moderately high risk for recurrent VT/VF and who were not candidates for spironolactone by current heart failure guidelines were randomized to receive spironolactone 25 mg daily or placebo in a double-blind fashion. All patients had previously received ICD therapy (shock or antitachycardia pacing) for VT/VF within 2 years of randomization or an ICD for secondary prevention of VT/VF within 6 months of randomization. The primary end point was time to first recurrence of VT/VF requiring ICD therapy. After a median follow-up of 35 months, the Kaplan-Meier probability estimates for VT/VF requiring ICD therapy were 68.7% in the placebo group and 84.7% in the spironolactone group. Compared with placebo, spironolactone was associated with a similar risk of VT/VF (hazard ratio, 1.01; 95% CI, 0.64-1.83; P=0.71). There was no significant difference between the median times to first VT/VF recurrence requiring ICD therapy in the 2 groups. Conclusions- In patients with ICDs who were at moderately high risk for recurrent VT/VF on account of a recent VT/VF event that was either sustained or treated by the ICD and who were not candidates for spironolactone by current heart failure guidelines, spironolactone did not delay the first recurrence of VT/VF or reduce the risk of recurrent VT/VF.     

Survival after cardiac arrest or sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy.

OBJECTIVES: The aim of this study was to evaluate the survival of patients with hypertrophic cardiomyopathy (HCM) after resuscitated ventricular fibrillation or syncopal sustained ventricular tachycardia (VT/VF) when treated with low dose amiodarone or implantable cardioverter defibrillators (ICDs). BACKGROUND: Prospective data on clinical outcome in patients with HCM who survive a cardiac arrest are limited, but studies conducted before the widespread use of amiodarone and/or ICD therapy suggest that over a third die within seven years from sudden cardiac death or progressive heart failure. METHODS: Sixteen HCM patients with a history of VT/VF (nine male, age at VT/VF 19 +/- 8 years [range 10 to 36]) were studied. Syncopal sustained ventricular tachycardia/ventricular fibrillation occurred during or immediately after exertion in eight patients and was the initial presentation in eight. One patient had disabling neurologic deficit after VT/VF. Before VT/VF, two patients had angina, four had syncope and six had a family history of premature sudden cardiac death. After VT/VF all patients were in New York Heart Association class I or II, three had nonsustained VT during ambulatory electrocardiography and 11 had an abnormal exercise blood pressure response. After VT/VF eight patients were treated with low dose amiodarone and six received an ICD. Prophylactic therapy was declined by two patients. RESULTS: Mean follow-up was 6.1 +/- 4.0 years (range 0.5 to 14.5). Cumulative survival (death or ICD discharge) for the entire cohort was 59% at five years (95% confidence interval: 33% to 84%). Thirteen (81%) patients were alive at last follow-up. Two patients died suddenly while taking low dose amiodarone, and one died due to neurologic complications of his initial cardiac arrest. Three patients had one or more appropriate ICD discharges during follow-up; the times to first shock after ICD implantation were 23, 197 and 1,124 days. CONCLUSIONS: This study shows that patients with HCM who survive an episode of VT/VF remain at risk for a recurrent event. Implantable cardioverter defibrillator therapy appears to offer the best potential benefit regarding outcome.     

Gender differences in ventricular arrhythmia recurrence in patients with coronary artery disease and implantable cardioverter-defibrillators

OBJECTIVES: We sought to determine whether men and women with coronary artery disease (CAD) and implantable cardioverter-defibrillators (ICDs) differ in frequency of arrhythmia recurrence and whether gender differences are independent of clinical, electrocardiographic, and electrophysiologic characteristics. BACKGROUND: Epidemiologic studies show that women have a lower rate of sudden cardiac death (SCD) than men, even among patients with CAD. Whether this is due to differing susceptibilities to ischemia or to arrhythmia is unknown. METHODS: The clinical records and ICD data disks of 340 men and 59 women with CAD who received an ICD between June 1990 and June 2000 were reviewed. Ventricular tachycardia (VT) or ventricular fibrillation (VF) recurrences were compared between genders and relationship with other factors was analyzed. RESULTS: Sustained VT/VF occurred in 52% of men and 34% of women (p < 0.01). Men experienced more total VT/VF events (p < 0.01), more shock-treated VT/VF events (p < 0.03), more electrical storms (p < 0.001), and had VT/VF on more days in follow-up (p < 0.01). Gender differences were independent of measured clinical, electrocardiographic, and electrophysiologic factors. In stratified analyses, the gender differences in VT/VF recurrence were greatest in patients presenting with sustained monomorphic VT and those with inducible VT at electrophysiology study. CONCLUSIONS: Women were less likely to experience VT/VF, and had fewer VT/VF episodes, than men. These findings were strongest in patients with evidence of a stable anatomic VT circuit: those with clinical or electrophysiologically induced VT. This study suggests that differing susceptibility to arrhythmia triggering may underlie the known differences in SCD rates between men and women.     

Ventricular arrhythmia storms in postinfarction patients with implantable defibrillators for primary prevention indications: a MADIT-II substudy.

BACKGROUND: Much of prognostic implications of ventricular arrhythmia storms remain unclear. OBJECTIVE: We evaluated the risk associated with electrical storm in patients with defibrillators in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) study. METHODS: Electrical storm was defined as > or =3 episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) in 24 hours. RESULTS: Of the 719 patients who received internal cardiac defibrillator (ICD) implants and had follow-up in the MADIT-II, 27 patients (4%) had electrical storm, 142 (20%) had isolated episodes of VT/VF, and the remaining 550 patients had no ICD-recorded VT events. Baseline clinical characteristics among the groups were similar. Patients who experienced electrical storm had a significantly higher risk of death. After adjustments for relevant clinical covariates, the hazard ratio (HR) for death in the first 3 months after the storm event was 17.8 (95% confidence interval [CI] 8.0 to 39.5, P <.01) in comparison with those with no VT/VF. This risk continued even after 3 months for those with electrical storm (HR of 3.5, 95% CI 1.2 to 9.8, P = .02). Study patients with isolated VT/VF episodes also were at an increased risk of dying (HR = 2.5, 95% CI 1.5 to 4.0, P <.01) when compared with patients without VT/VF episodes. Statistically significant predictors of electrical storm were interim postenrollment coronary events (myocardial infarction or angina) HR 3.1 (95% CI 1.2 to 8.1, P = .02) and isolated VT or VF HR 9.2 (95% CI 4.0 to 20.9, P <.01). CONCLUSION: Postinfarction patients with severe left ventricular dysfunction in whom electrical storm developed have significantly higher mortality than patients with only isolated VT/VF as well as those without any episodes of VT/VF. Patients who experienced postenrollment ventricular arrhythmias and/or interim coronary events during follow-up were at higher risk for VT/VF storms.     

植入型心律转复除颤器治疗的适应证

致命性室性心律失常（室性心动过速／心室颤动）是心脏性猝死（SCD）的主要原因，美国每年约40万人死于此症。一系列多中心临床试验证明ICD是优于药物的有效治疗方法，明显降低SCD发生率。美国每年上万人安装ICD，其数量呈直线上升趋势。我国由于经济条件和认识水平普及的限制，采用ICD治疗的患者甚少，但近年来逐渐增多，1年约100例患者安装ICD。为提高医生和患者对应用ICD的认识及使用规范化，两个学会的ICD专家组于2001年11月在北京召开研讨会，就ICD适应证、多中心试验结果、植入技术、心动过速的识别和治疗、并发症、随诊等专题，结合我国实际情况，进入了深入和认真的讨论，并提出建议。     

Occurrence of implantable cardioverter-defibrillator therapy in clinical practice

The landmark trials MADIT II, SCD-HeFT, and COMPANION in 2002–2005 years have reported their positive results to sudden cardiac death reduction. Since that time the indications for the use of implantable cardioverter-defibrillators (ICDs) have substantially broadened. The occurrence of appropriate ICD therapy differs in the individual trials. We were retrospectively analyzing the occurrence of ventricular tachycardia/ventricular fibrillation (VT/VF) from ICD remote monitoring database (Biotronik Home Monitoring TM, www.biotronik-homemonitoring.com). No significant difference was found between subgroups divided by the implantation indication, the programmed ventricular stimulation, the aggressivity of programmed ventricular stimulation protocol, left ventricular ejection fraction, ICD types, percentage of right ventricular pacing, diabetes mellitus, renal dysfunction and gender. VT/VF occurred statistically significantly more often in patients with non-sustained VT on the preimplant Holter monitoring report in patients with primary preventive indication for postinfarction coronary artery disease but not in primary preventive indication for non-ischemic dilated cardiomyopathy. We observed higher VT/VF occurrence in patients with preimplant syncope or presyncope even higher than in patients after cardiopulmonary resuscitation. There was a visible trend for higher VT/VF occurrence in patients with positive programmed ventricular stimulation especially with less aggressive protocol and in patients with left ventricular ejection fraction of 30% and less. Authors found the preimplant nonsustained ventricular tachycardia (NSVT) on Holter monitoring as the only independent predictor of VT/VF occurrence.     

Implantable cardioverter defibrillator shocks from ventricular tachyarrhythmias in patients with ischemic heart disease: Preventative measures,shortcomings, cost-effectiveness,and global practice perspectives

Implantable cardioverter defibrillators (ICDs) have proven to be life-saving devices in patients with ischemic cardiomyopathy (ICM) who are prone to develop ventricular tachycardia (VT) and fibrillation (VF). Antiarrhythmic drugs (AADs) are commonly prescribed in many such patients with ICDs to treat and prevent different forms of arrhythmias in clinical practice. When these patients experience recurrent monomorphic VT despite chronic AADs therapy, or when AAD therapy is contraindicated or not tolerated, and VT storm is refractory to AAD therapy, catheter ablation constitute guideline-based class I indication of treatment. However, what should be the most appropriate strategy to prevent first ICD shock or subsequent multiple shocks from VT/VF in patients with ICM who undergo ICD implantation without prior incidence of cardiac arrest, remains debatable. The purpose of this review is to discuss preventative aspects of ICD shocks for VT and the shortcomings of these measures along with the cost-effectiveness and global perspectives based on the current knowledge of the topic.     

Differences in Outcomes Between Patients Treated with Single‐ versus Dual‐Chamber Implantable Cardioverter Defibrillators: A Substudy of the Multicenter Automatic Defibrillator Implantation Trial II

Objectives: We sought to evaluate the influence of single‐ versus dual‐chamber implantable cardioverter defibrillators (ICDs) on the occurrence of heart failure and mortality as well as appropriate and inappropriate ICD therapy in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT‐II). Background: In MADIT‐II, ICD therapy in patients with a prior myocardial infarction and ejection fraction ≤0.30 was associated with a 31% reduction in risk of mortality when compared to conventionally treated patients. An unexpected finding was an increased occurrence of hospitalization for heart failure in the ICD group. Methods: Data from 717 patients randomized to ICD therapy with single‐ or dual‐chamber pacing devices in MADIT‐II were retrospectively analyzed. Endpoints selected for analysis included death from any cause, new or worsening heart failure requiring hospitalization, death or heart failure, appropriate therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF), and inappropriate ICD therapy for atrial fibrillation or supraventricular tachycardia. Results: A total of 404 single‐chamber ICDs (S‐ICDs) and 313 dual‐chamber ICDs (D‐ICDs) were implanted. Patients receiving D‐ICDs were at a higher risk at baseline than those receiving S‐ICDs, with older age, higher NYHA class, more frequent prior CABG, wider QRS complex, more LBBB, higher BUN level, a history of more atrial arrhythmias requiring treatment, and a longer time interval from their index myocardial infarction to enrollment. While there was a trend toward an increase in adverse outcomes in the D‐ICD group, no statistically significant differences in heart failure or mortality were observed between S‐ICD versus D‐ICD groups. Conclusions: Patients with D‐ICDs had a nonsignificant trend toward higher mortality and heart failure rates than patients with S‐ICDs.