Sudden cardiac death after acute heart failure hospital admission: insights from ASCEND‐HF

Aims

The incidence of and factors associated with sudden cardiac death (SCD) early after an acute heart failure (HF) hospital admission have not been well defined.

Methods and results

We assessed SCD and ventricular arrhythmias in the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure (ASCEND‐HF) trial, which included patients with acute HF with reduced or preserved ejection fraction. SCD, resuscitated SCD (RSCD), and sustained ventricular tachycardia/ventricular fibrillation (VT/VF) were adjudicated from randomization through 30 days and were combined into a composite endpoint. Baseline characteristics associated with this composite were determined by logistic regression. RSCD and VT/VF were included as time‐dependent variables in a Cox model evaluating the association of these variables with 180‐day all‐cause mortality. Among 7011 patients, the 30‐day all‐cause mortality rate was 3.8%; SCD accounted for 17% of these deaths. The 30‐day composite event rate was 1.8% (n = 121). Ten patients had more than one event with 30‐day Kaplan–Meier event rates of 0.6% for SCD [95% confidence interval (CI) 0.5%–0.9%, n = 43], 0.4% for RSCD (95% CI 0.2%–0.5%, n = 24), and 0.9% for VT/VF (95% CI 0.7%–1.2%, n = 64). In the multivariable model, chronic obstructive pulmonary disease, history of VT, male sex, and longer QRS duration were associated with SCD, RSCD, or VT/VF. A RSCD or VT/VF event was associated with higher 180‐day mortality (adjusted hazard ratio 6.6, 95% CI 4.8–9.1, P < 0.0001).

Conclusions

Approximately 2% of patients admitted for acute HF experienced SCD, RSCD, or VT/VF within 30 days of admission, and SCD accounted for 17% of all deaths within 30 days.     

Effect of first ventricular tachycardia cycle length on rate of ventricular arrhythmia recurrence in patients with implantable cardioverter-defibrillator

Background

Some controversies exist regarding the proper treatment of hemodynamically tolerated and slow ventricular tachycardia (VT). We intended to assess the effect of cycle length of first VT episode on total ventricular arrhythmia burden in a cohort of patients with implantable cardioverter-defibrillator (ICD).

Method

Between March 2000 and March 2005, 195 patients underwent ICD implantation at our center. We included 158 patients (mean age, 58.3 ± 12.9 years) with follow-up of 3 months or more in this study. Clinical, electrocardiographic, and ICD-stored data and electrograms were collected and analyzed.

Results

During the follow-up of 16.7 ± 10.6 months, 45 (28.5%) and 20 (12.6%) patients received first appropriate ICD therapy for VT and ventricular fibrillation, respectively. We divided the 45 patients with VT (based on the median value of VT cycle length) into 2 groups. Although patients with VT cycle length of less than 350 had higher total mean number of appropriate ICD therapy (25 vs 6.3, P = .023), during multivariate regression analysis, only left ventricular ejection fraction (EF) of less than 25% (P = .020) was correlated with total number of appropriate ICD therapy. First VT cycle length (P = .341), QRS duration (P = .126), age (P = .405), underlying heart disease (P = .310), indication of ICD implantation (P = .113), and sex (P = .886) have failed to predict the total burden of ventricular arrhythmia during the follow-up period.

Conclusion

After adjustment for left ventricular EF, initial VT cycle length per se did not confer a lower risk for subsequent ventricular arrhythmia recurrence compared with those with faster VT. Left ventricular EF of less than 25% was correlated with higher ventricular arrhythmia burden in patients with ICD.     

Role of catheter ablation of ventricular tachycardia associated with structural heart disease

In patients with structural heart disease, ventricular tachycardia (VT) worsens the clinical condition and may severely affect the shortand long-term prognosis. Several therapeutic options can be considered for the management of this arrhythmia. Among others, catheter ablation, a closed-chest therapy, can prevent arrhythmia recurrences by abolishing the arrhythmogenic substrate. Over the last two decades, different techniques have been developed for an effective approach to both tolerated and untolerated VTs. The clinical outcome of patients undergoing ablation has been evaluated in multiple studies. This editorial gives an overview of the role, methodology, clinical outcome and innovative approaches in catheter ablation of VT.     

Implantable cardioverter-defibrillator therapy and risk of congestive heart failure or death in MADIT II patients with atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) contributes to increased risk of morbidity and mortality. Data regarding the effectiveness of implantable cardioverter-defibrillator (ICD) therapy in AF patients are limited. OBJECTIVES: The purpose of this study was to evaluate the effectiveness of ICD therapy in patients with AF enrolled in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) and to identify their risk for the combined endpoint of hospitalization for congestive heart failure or death. METHODS: The MADIT II cohort served as the source for data on the clinical course, cardiac events, and effectiveness of ICD therapy in AF patients. RESULTS: AF was found as baseline rhythm at enrollment in 102 (8%) MADIT II patients. In comparison to 1,007 patients in sinus rhythm, AF patients were older, more frequently were males, had wider QRS complex, and had higher blood urea nitrogen and creatinine levels (P <.05 for all parameters). ICD therapy was effective in reducing 2-year mortality in AF patients from 39% in 41 conventionally treated patients to 22% in 61 ICD-treated patients (hazard ratio = 0.51, P = .079). However, the combined endpoint of hospitalization for heart failure or death at 2 years was 69% and 59%, respectively (NS). AF was predictive for the combined endpoint of heart failure hospitalization or death (hazard ratio = 1.68, P = .040). New-onset AF in patients with baseline sinus rhythm was associated with increased risk of mortality (hazard ratio = 2.70, P <.001). CONCLUSION: MADIT II patients with AF benefit from ICD therapy, which reduces their mortality. MADIT II patients with AF are at high risk for developing heart failure.     

Right ventricular pacing and the risk of heart failure in implantable cardioverter-defibrillator patients

BACKGROUND: Right ventricular (RV) pacing in implantable cardioverter-defibrillator (ICD) patients may have detrimental effects on morbidity and mortality, in particular by inducing heart failure (HF). OBJECTIVE: We investigated whether RV pacing increases the risk of HF in an asymptomatic ICD population. METHODS: We evaluated all patients without symptomatic HF who received an ICD. The primary endpoint was the occurrence of HF, which was defined as new HF, hospitalization for HF, or death due to HF. The secondary endpoint was appropriate shocks. RESULTS: The study population consisted of 456 patients with mean left ventricular ejection fraction (LVEF) 40% +/- 13%. Mean follow-up was 31 +/- 22 months. Because of the bimodal distribution of pacing, patients were divided into two groups: paced 50% (median 96%; n = 143). HF occurred more often in the paced >50% group (20% versus 9%; P <.001). Multivariate analysis identified RV pacing >50% (adjusted hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.08-3.15; P = .03), baseline LVEF <26% (adjusted HR 3.15; 95% CI 1.77-5.59; P <.001), angina pectoris, history of atrial fibrillation, and baseline diuretic use as independent predictors of HF. RV pacing caused more HF events in patients with LVEF <26% (n = 64; 55% of paced >50% patients versus 20% of paced 50% also independently predicted appropriate shocks (adjusted HR 1.50; 95% CI 1.02-2.20; P = .04). CONCLUSION: RV pacing was associated with an increased risk of HF in asymptomatic ICD patients, particularly in those with preexistent left ventricular dysfunction.     

Impact of accelerated ventricular tachyarrhythmias on mortality in patients with implantable cardioverter-defibrillator therapy

Background

Anti-tachycardia pacing (ATP) and shock delivery may induce or accelerate tachyarrhythmias in patients with implantable cardioverter-defibrillator (ICD). We investigated the incidence, triggers and impact on mortality of accelerated ventricular tachyarrhythmias.

Methods

Database analysis concerning ventricular tachyarrhythmias accelerated by ATP or shock in 1275 ICD patients (age at implantation 59.7 ± 14.0 years; 81% male).

Results

Within a mean follow-up period of 5.3 ± 4.0 years, intracardiac electrograms were available in 1170 patients (91.8%). Overall 157 episodes of accelerated ventricular tachyarrhythmias were found in 100 of 1170 patients (8.5%). Termination of tachyarrhythmias was achieved by shock delivery in 153 episodes (96.8%). Triggers of accelerated tachyarrhythmias were appropriate ATP in 139 (88.5%) and inappropriate ATP in 14 (8.9%), as well as appropriate and inappropriate shocks in 2 (1.3%) episodes, respectively. Chronic heart failure was significantly correlated with the occurrence and recurrence of acceleration (p < 0.001). Patients with accelerated ventricular tachyarrhythmia and subsequent shock therapy revealed higher all-cause mortality (HR 1.760; 95% CI 1.286–2.410; p < 0.001) as well as higher cardiac mortality (HR 2.555; 95% CI 1.446–4.513; p = 0.001). The correlation between acceleration and all-cause mortality was independent of left ventricular function (HR 2.076; 95% CI 1.633–2.639; p < 0.001).

Conclusions

Ventricular ATP with arrhythmia acceleration and subsequent shock delivery is a frequent and serious complication of ICD therapy that predominantly occurs in patients with reduced left ventricular function. Finally, occurrence of accelerated ventricular tachyarrhythmias was associated with increased all-cause mortality.     

Incidence of nonsustained and sustained ventricular tachyarrhythmias in patients with an implantable cardioverter defibrillator

INTRODUCTION: Nonsustained ventricular tachycardia (NSVT) is a frequent phenomenon in some patients with heart disease, but its association with sustained ventricular tachycardias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) is still not clear. The aim of this study was to determine whether NSVT incidence was associated with sustained VT/VF in patients with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: Retrospective data analysis was conducted in 923 ICD patients with a mean follow-up of 4 months. NSVT and sustained VT/VF were defined as device-detected tachycardias. The incidence rates of NSVT and sustained VT/VF as well as ICD therapies were determined as episodes per patient. The NSVT index was defined as the product of NSVT episodes/day times the mean number of beats per episode, i.e., total beats/day. The NSVT index peak was defined as the highest value on or prior to the day with sustained VT/VF episodes. Patients (n = 393) with NSVT experienced a higher incidence of sustained VT/VF (17.2 +/- 63.0 episodes/patient) and ICD therapies (15.2 +/- 61.4 episodes/patient) than patients (n = 530) without NSVT (sustained VT/VF: 0.5 +/- 6.6 and therapies: 0.5 +/- 5.6; P < 0.0001). Approximately 74% of NSVT index peaks occurred on the same day or <3 days prior to sustained VT/VF episodes. The index was higher for peaks < or =3 days prior to the day with sustained VT/VF (94.3 +/- 140.1 total beats/day) than for peaks >3 days prior to the day with sustained VT/VF (32.7 +/- 55.9 total beats/day; P < 0.0001). CONCLUSION: ICD patients with NSVT represent a population more likely to experience sustained VT/VF episodes with a temporal association between an NSVT surge and sustained VT/VF occurrence.     

Repolarization heterogeneity in patients with cardiac resynchronization therapy and its relation to ventricular tachyarrhythmias

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The role of the transvenous catheter electrophysiologic study in the evaluation and management of ventricular tachyarrhythmias associated with ischemic heart disease

The transvenous-catheter electrophysiologic (EP) study has occupied a central position in the investigation and management of patients with ischemic heart disease and a propensity to ventricular tachycardia (VT) or ventricular fibrillation (VF) for more than 25 years. However, demonstration of the superiority of the implantable cardioverter defibrillator (ICD) compared to other approaches to the management of VT/VF has resulted in a decrease in the frequency of use of the EP study in these patients. Nevertheless, the EP study remains a value-added procedure for many patients in this setting. These advantages include demonstration that the clinical arrhythmia is VT/VF when the diagnosis is uncertain, identification of those patients whose VT/VF is actually the result of a supraventricular tachyarrhythmia, identification of VT mechanisms readily amenable to catheter ablation, assessment of the response of a patient's VT to attempts at pace-termination, evaluation of candidacy for ablative VT therapy, prediction of the efficacy of approaches to prevention of VT/VF episodes, risk stratification of patients who have not yet experienced a sustained episode of VT/VF, and continued enhancement of our understanding of the mechanisms and therapeutics of VT/VF. The purpose of this review is to outline our present understanding of the techniques and indications for an EP study in patients with ischemic heart disease.     

植入型心律转复除颤器抗心动过速起搏治疗室性心动过速疗效评价

目的恶性室性心律失常（室性心动过速,心室颤动）是心脏性猝死的主要直接原因.而大部分患者先发生室性心动过速（室速）,继而蜕变为心室颤动（室颤）.研究表明,抗心动过速起搏（ATP）可有效终止室速.本文观察了172例植人植入型心律转复除颤器（ICD）的患者应用ATP终止室速的效果.方法172例植入ICD的患者,男性137例,女性35例,平均年龄52.8岁.103例患者术前有阿-斯综合征发作史,其中75例有电击除颤史.137例术前记录到室速或室颤心电图.植入ICD患者定期随访,随访时应用体外程控仪调出ICD储存记录,分析ICD治疗中ATP治疗室速的效果.结果在平均随访37个月中,ICD共记录室速l 789阵.其中,316阵为短阵室速,在ICD治疗前自行终止;1 473阵室速接受了ICD有效治疗.其中ATP治疗成功981阵（成功率66.6%）,余492阵室速由低能量转复终止.在981阵ATP治疗成功的事件中,ICD第一次发放ATP成功终止室速513阵（成功率52.3%）.结论ICD抗室速起搏功能可有效终止大多数室速,对于植入ICD前有明确室速史的患者,ICD治疗应尽量先采用ATP治疗,以减少ICD放电,延长ICD使用寿命及避免电击时的痛苦,即所谓的＂无痛性ICD治疗＂.     

慢性收缩性心力衰竭患者室性心律失常的特点及影响因素

目的 了解慢性收缩性心力衰竭(chronic systolic heart failure,CSHF)住院患者室性心律失常的发生特点及影响因素.方法 回顾性调查和分析湖北地区8地市共12家三级甲等医院2000年至2010年CSHF住院患者资料,单因素和多因素logistic回归分析室性早搏(室早)和室性心动过速(室速)相关危险因素.根据年龄将患者分为≤40岁、41～50岁、51～60岁、61～70岁、71～80岁和≥81岁组；根据心功能分为Ⅰ、Ⅱ、Ⅲ、Ⅳ级(NYHA分级)组；根据左心室射血分数(LVEF)将患者分为LVEF0.41 ～0.50、0.31～0.40、0.21 ～0.30和≤0.20组；根据心力衰竭病因将患者分为冠心病、风湿性心脏病(风心病)、高血压性心脏病(高心病)和扩张型心脏病(扩心病)组.结果 ①CSHF患者室早和室速的发生率分别为68.30％和14.52％.②多因素logistic回归分析发现:室早和室速的发生风险(HR)在各年龄组间差异无统计学意义；不同心功能组间差异无统计学意义；与冠心病组相比,风心病、高心病和扩心病组室早和室速HR分别为0.430(95％ CI,0.381～0.497,P＜0.01)、0.559 (95％ CI,0.322～0.743,P＜0.01)、1.297(95％ CI,1.132～1.486,P＜0.01)和0.530(95％ CI,0.421～0.652,P＜0.01) 、0.896(95％ CI,0.775 ～ 1.211,P=0.358)、12.111 (95％CI,9.820 ～ 14.937,P＜0.01)；室速HR随LVEF降低而显著增加(与LVEF 0.41 ～ 0.50组相比,LVEF 0.31 ～0.40、0.21 ～0.30和≤0.20组室速HR分别为1.760(95％CI,1.218 ～2.345,P＜0.01)、2.396(95％ CI,2.019～2.783,P＜0.01)和4.209(95％ CI,3.554 ～4.862,P＜0.01),但LVEF各组间室早HR差异无统计学意义.结论 CSHF患者室早和室速的发生率高；室速HR随LVEF减低而增加；不同病因引起的CSHF患者并发室早和室速情况各不相同.     

Trends in treated ventricular fibrillation out-of-hospital cardiac arrest: A 17-year population-based study

OBJECTIVES: The aims of this study were to describe the trends of ventricular fibrillation (VF) out-of-hospital cardiac arrest in Rochester, Minnesota, since 1985 and to determine coexistent trends in implantable cardioverter defibrillator (ICD) placement and termination of potentially lethal ventricular arrhythmias that might explain, at least in part, a declining incidence trend. BACKGROUND: The incidence of VF out-of-hospital cardiac arrest treated by emergency medical services (EMS) personnel has declined over the past decade. Because VF out-of-hospital cardiac arrest occurs primarily in the setting of severe coronary artery disease, primary and secondary prevention strategies may account in part for the decline. In particular, ICD use in large primary and secondary prevention clinical trials in patients at high risk of sudden death has demonstrated that these devices improve survival. METHODS: All residents of the City of Rochester, Minnesota, who presented with a VF out-of-hospital cardiac arrest from 1985 to 2002, identified and treated by EMS, were included in the study. In addition, residents of the City of Rochester who received their first ICD implant from 1989 to 2002 were identified. From the ICD records, general demographics, etiology of heart disease, comorbid medical disease, and indication for ICD placement were abstracted. Follow-up data obtained from this population included ICD shocks, the underlying rhythm disturbance, and death. RESULTS: The overall incidence of EMS-treated VF out-of-hospital cardiac arrest in Rochester during the study period was 17.1 per 100,000 [95% confidence interval (CI) 15.1-19.4]. The incidence has decreased significantly (P < 0.001) over the study period: 1985-1989: 26.3/100,000 (95% CI 21.0-32.6), 1990-1994: 18.2/100,000 (95% CI 14.1-23.1), 1995-1999: 13.8/100,000 (95% CI 10.4-17.9), 2000-2002: 7.7/100,000 (95% CI 4.7-11.9). One hundred ten patients received an ICD. The placement of ICDs also has increased dramatically over the past 10 years: 1990-1994: 5.0/100,000 to 2000-2002: 20.7/100,000 (P < 0.001). ICDs terminated VF or fast ventricular tachycardia (<270 ms) in 22 patients. Termination of these potentially fatal arrhythmias has shown a trend toward an increase over the study period: 1990-1994: 1.1/100,000 to 2000-2002: 3.5/100,000 (P = 0.06). CONCLUSIONS: The incidence of VF out-of-hospital cardiac arrest is declining. In contrast, the rates of ICD placement and ICD termination of ventricular tachycardia or VF are markedly increasing. Sudden death preventive strategies are multifactorial. These observations suggest that ICD termination of potentially lethal ventricular arrhythmias may contribute to the lower incidence of VF out-of-hospital cardiac arrest.