Sudden death prophylaxis in heart failure

Sudden cardiac death (SCD) is the leading cause of mortality in heart failure (HF). Today the implantable cardioverter-defibrillator (ICD) has become a commonplace therapy around the world for patients with both ischemic and non-ischemic cardiomyopathy and an ejection fraction (EF) < or = 35%. However, EF alone does not discriminate between the modes of death from HF (sudden arrhythmic death vs. non-sudden death). Other risk statifiers, such as electrophysiologic study and microvolt T-wave alternans testing, should therefore be used in the appropriate settings to minimize the number of unnecessary device implants. In addition, left ventricular mechanical dyssynchrony has now become recognized as an additional major marker of cardiac mortality. Its assessment should entail echocardiography rather than measurement of the QRS duration. This will allow us to better integrate the ability of cardiac resynchronization therapy (CRT) in enhancing cardiac function with the ability of an ICD in preventing SCD. This review aims to: 1) give a synthesis of the published evidence regarding the value of implantable ICDs and CRT in the primary prophylaxis of SCD in HF; 2) discuss controversial clinical issues in this area; and 3) recommend practical device-based management strategies.     

Implantable device therapy

Sudden cardiac death (SCD) accounts for two-thirds of fatal events related to heart disease. Coronary heart disease and non-ischemic cardiomyopathy are the most common causes of SCD. Data from major randomized trials have consistently shown that therapy with an implantable cardioverter defibrillator (ICD) results in a significant and meaningful effect on survival through a reduction in the risk of SCD in these population. These data have resulted in a marked increase in the application of implantable device therapy in the past 2 decades from secondary prevention with an implantable cardioverter/defibrillator (ICD) in survivors of a cardiac arrest to primary prevention of SCD in asymptomatic patients with ischemic and non-ischemic left ventricular dysfunction, and prevention of symptomatic heart failure progression and death with cardiac resynchronization therapy (CRT), and devices that combine CRT and ICD therapies (CRT-D). However, there are still areas of uncertainty regarding device therapy that include inconsistent benefit in risk-subgroups of patients with low ejection fraction; increased risk of heart failure after life-prolonging ICD therapy, and a considerable rate of device malfunction despite increasing sophistication. In the present review we focus on current data regarding the clinical indications as well as the safety and efficacy of implantable device therapy, including ICD, CRT, and CRT-D.     

Electrical devices for left ventricular dysfunction and heart failure: do we need revised guidelines?

Three recent trials have demonstrated the benefit of cardiac resynchronization therapy (CRT) in the New York Heart Association (NYHA) class II patients with heart failure (HF) with ischemic or nonischemic cardiomyopathy as well as in NYHA class I (asymptomatic) patients mostly with ischemic cardiomyopathy. Earlier intervention with CRT in asymptomatic or minimally symptomatic patients improves survival and reduces HF hospitalizations. The reduction or the prevention of HF hospitalizations is of paramount importance because the HF episodes seem to alter the natural history of disease and are associated with deterioration of left ventricular (LV) function and a marked increase in mortality. The CRT benefit is greatest in patients with a QRS ≥ 150 ms. At this time, it would seem prudent to consider CRT-D (D = ICD) therapy for class I NYHA patients with a QRS ≥ 150 ms and an LV ejection fraction ≤ 30% regardless of etiology. Although the data for NYHA class I patients with nonischemic cardiomyopathy are scanty, the recommendation for class I patients is justified because CRT achieves a much greater degree of LV reverse remodeling in nonischemic compared to ischemic patients. With regard to lone ICDs, there is no evidence that they prevent sudden cardiac death more efficiently in symptomatic than in asymptomatic patients. Cardiomyopathy should be the primary target for device therapy regardless of symptoms for both CRT and lone ICD therapy. New guidelines are needed to address the role of CRT in hospitalized NYHA class IV HF patients or those who depend on inotropic therapy or an LV assist device because randomized CRT trials have not included these patients. CRT in these patients remains controversial. The mortality of such patients even with CRT is very high despite the occasional positive response. The role of CRT in patients waiting for cardiac transplantation also needs guidelines. With the expansion of CRT indications to minimally symptomatic or asymptomatic patients, the benefit of device therapy must be carefully weighed against the potential risk of lifelong device complications.     

The current role of cardiac resynchronization therapy in reducing mortality and hospitalization in heart failure patients: a meta-analysis from clinical trials

Many diagnostic and therapeutic advances have been reached for congestive heart failure (HF). However, despite clinical improvement and longer survival conferred by new pharmacological options, this syndrome is associated with high morbidity and mortality. Atrial-synchronized biventricular pacing (cardiac resynchronization therapy, CRT) has proven to be effective treatment in symptomatic patients with reduced left ventricular ejection fraction and electromechanical dyssynchrony. To date, many papers have been published on the role of CRT in improving quality of life, functional and neurohormonal parameters and reducing mortality and hospitalization. Eligible studies were randomized controlled trials of CRT for the treatment of chronic, symptomatic left ventricular dysfunction. Our search began dating back to 1994 and was updated to October 2006. Pooled data from the 6 selected studies showed that CRT reduced all-cause mortality by 28% (hazard ration [HR] = 0.72; 95% confidence interval [CI]: 0.60-0.86) and new hospitalizations for worsening HF by 37% (HR = 0.63; 95% CI: 0.44-0.91). This meta-analysis showed that patients with implantable cardiac defibrillators (ICDs) alone and ICD+CRT had a significant reduction of worsening HF hospitalization rate compared to no CRT-no ICD patients. Among patients with ICDs, CRT showed a slight effect on all-cause mortality reduction but no clear impact on worsening HF rehospitalization.     

The role of prophylactic implantable cardioverter defibrillators in heart failure: Recent trials usher in a new era of device therapy

Sudden cardiac death (SCD) manifested as ventricular fibrillation or sustained ventricular tachycardia has been a major focus of cardiovascular research for more than three decades. Although mortality in patients with heart failure (HF) caused by left ventricular systolic dysfunction has declined in recent years through effective pharmacotherapeutic strategies, SCD remains the major cause of death in symptomatic HF, with little improvement by drug therapy. Although it is clear that the implantable cardioverter defibrillator (ICD) is efficacious and should be used to prevent a recurrence of sustained ventricular arrhythmia (secondary prevention) in most patients, the guidelines for prophylactic use of ICDs (primary prevention) are less well defined. The results of recent clinical trials examining the efficacy of prophylactic ICD therapy in HF patients have clarified the role of ICD treatment in this population. This article reviews these trials and summarizes our current approach to the prevention of SCD in HF.     

Device therapy in heart failure patients with chronic kidney disease

Heart failure (HF) and chronic kidney disease (CKD) both carry significant risk for sudden cardiac death, hospitalization, and mortality; when combined, however, they markedly increase the risk of morbidity and mortality. Device therapies such as implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) are treatments proven to have significant benefit on clinical outcomes in select patients with HF. However, the majority of studies supporting the use of these devices have limited data on patients with CKD or end-stage renal disease. In this review, we discuss the intersection of HF and CKD as it relates to progressive HF and the risk of sudden death. Although these disorders are common and have a poor prognosis, the evidence available for guiding treatment decisions for the use of ICD and CRT devices in these patients is lacking. Given this lack of clear evidence, pragmatic clinical trials and comparative effectiveness studies are needed to help identify the appropriate use of ICD and CRT devices in this high-risk population of patients with HF and CKD.     

Need and evolution of need for device therapy in a community heart failure population

BACKGROUND: New guidelines for implantable cardiac defibrillators (ICD) and cardiac resynchronisation therapy (CRT) have expanded the potential use for device therapy. The implications of this on a community heart failure (HF) population are unknown. AIM: To assess the need for device therapy and the change in need over time. METHODS: We reviewed device need in a community HF population using ESC guidelines. Change in need was assessed by comparing data between an annual visit called TP2 and an earlier visit called TP1. Patients' need and change in need between TP1 and TP2 was determined. RESULTS: 210 patients were included; mean age 70+/-12 years, 67% male and 54% ischaemic. At TP1, 34% of patients were suitable for ICD and 3% for CRT. At TP2, 22% and 1% were suitable respectively. Of those suitable for ICD at TP1, 19% lost the need at TP2; in addition 9% of patients unsuitable for ICD at TP1 had acquired the need by TP2. Fifty five percent of patients were unsuitable for ICD at either time point, and 16% were suitable at both time points. CRT need was negligible but also noted to change. CONCLUSION: ICD need is substantial in a community HF population, but CRT need is limited. ICD need changes significantly. Identifying those likely to change their need may optimise ICD use.     

植入心律转复除颤器作为心力衰竭患者心脏性猝死的一级预防

心力衰竭是多种心脏疾病发展至晚期的一个严重临床综合征,随着人口老龄化速度的加快、心血管疾病发病率的上升,心脏疾病尤其是心肌梗死的有效治疗使更多的患者得以生存,但随后慢性心力衰竭患者日趋增多。心力衰竭最终死亡原因主要是进行性心力衰竭加重和／或心脏性猝死（SCD）。     

Cardiac resynchronization therapy for the treatment of heart failure in patients with intraventricular conduction delay and malignant ventricular tachyarrhythmias

OBJECTIVES: This study was conducted to assess the safety and effectiveness of cardiac resynchronization therapy (CRT) when combined with an implantable cardioverter defibrillator (ICD). BACKGROUND: Long-term outcome of CRT was measured in patients with symptomatic heart failure (HF), intraventricular conduction delay, and malignant ventricular tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) requiring therapy from an ICD. METHODS: Patients (n = 490) were implanted with a device capable of providing both CRT and ICD therapy and randomized to CRT (n = 245) or control (no CRT, n = 245) for up to six months. The primary end point was progression of HF, defined as all-cause mortality, hospitalization for HF, and VT/VF requiring device intervention. Secondary end points included peak oxygen consumption (VO(2)), 6-min walk (6 MW), New York Heart Association (NYHA) class, quality of life (QOL), and echocardiographic analysis. RESULTS: A 15% reduction in HF progression was observed, but this was statistically insignificant (p = 0.35). The CRT, however, significantly improved peak VO(2) (0.8 ml/kg/min vs. 0.0 ml/kg/min, p = 0.030) and 6 MW (35 m vs. 15 m, p = 0.043). Changes in NYHA class (p = 0.10) and QOL (p = 0.40) were not statistically significant. The CRT demonstrated significant reductions in ventricular dimensions (left ventricular internal diameter in diastole = -3.4 mm vs. -0.3 mm, p < 0.001 and left ventricular internal diameter in systole = -4.0 mm vs. -0.7 mm, p < 0.001) and improvement in left ventricular ejection fraction (5.1% vs. 2.8%, p = 0.020). A subgroup of patients with advanced HF (NYHA class III/IV) consistently demonstrated improvement across all functional status end points. CONCLUSIONS: The CRT improved functional status in patients indicated for an ICD who also have symptomatic HF and intraventricular conduction delay.     

Analysis of mortality events in the Multicenter Automatic Defibrillator Implantation Trial (MADIT-II)

OBJECTIVES: The purpose of this study was to determine the efficacy of implantable cardiac defibrillator (ICD) therapy in preventing sudden cardiac death (SCD) in post-infarction patients with advanced left ventricular (LV) dysfunction. BACKGROUND: The Multicenter Automatic Defibrillator Implantation Trial (MADIT-II) randomized 1,232 post-infarction patients with an ejection fraction of < or =30% to ICD or conventional therapy. In the ICD group, there was a 31% decrease in the risk of total mortality. However, a better understanding of the mode of death is desirable in order to refine therapeutic interventions in high-risk populations. METHODS: We evaluated the 202 deaths, using a variation of the Hinkle-Thaler classification system as well as a clinical classification system to determine the incidence of SCD and the incidence of cardiac death due to progressive LV failure. RESULTS: The SCD rates were 10.0% in the conventional group and 3.8% in the ICD group (p < 0.01). The hazard ratio for the risk of SCD in the ICD group compared with the conventional therapy group was 0.33 (95% confidence interval 0.20 to 0.53, p < 0.0001). The ICD had no meaningful effect on non-sudden death (p = 0.32). The effect of defibrillator therapy in reducing SCD was similar in subgroup analyses stratified according to relevant baseline characteristics. CONCLUSIONS: The decrease in mortality with ICD therapy in MADIT-II is entirely due to a reduction in SCD, with similar reductions in SCD in a spectrum of subgroups stratified according to relevant baseline characteristics.     

Are women worldwide under-treated with regard to cardiac resynchronization and sudden death prevention?

Implantable cardioverter defibrillators (ICDs) have been demonstrated to improve survival in patients with serious structural heart disease. Likewise, cardiac resynchronization therapy (CRT) has assumed an important role in the treatment of patients with symptomatic heart failure because of its demonstrated value in improving functional class, quality of life, exercise capacity, and survival. However, these clinical trials have all primarily enrolled Caucasian males, raising the question as to whether other important subgroups benefit in a comparable way. Women have lower rates of sudden cardiac death (SCD) compared to men, and event rates lag 10–20 years behind those in men. Among patients with known coronary artery disease, women have one-fourth the risk of SCD found in men. Women with heart failure tend to present at an older age than men, and women more often have heart failure with preserved systolic function, a group in whom prophylactic ICD therapy for the prevention of SCD has not been studied. Despite these differences, analysis of clinical trial results shows that women have similar outcomes with ICD and CRT therapy compared to men. There is a lower percentage of women among device therapy patients both in clinical trials and in practice for reasons that are not clear, but at least some of the difference is likely due to differences in age at presentation and co-morbidities. In fact, device therapy overall appears to be under-utilized in both men and women, when implantation rates are compared to the prevalence of heart failure in the population as a whole.     

Sudden cardiac death in nonischemic cardiomyopathy

Sudden cardiac death (SCD) is a major cause of mortality in patients with nonischemic cardiomyopathy (NICM). Identifying patients who are at highest risk for SCD is an ongoing challenge. At present, guidelines recommend the use of an implantable cardioverter-defibrillator (ICD) in patients with NICM with a reduced left ventricular ejection fraction (LVEF) and heart failure (HF) symptoms. Some recent data, however, suggest that ICDs may not increase longevity in this population. Conversely, community-based studies have demonstrated that many at-risk individuals who may benefit from ICD therapy remain unprotected. Current recommendations for ICD implantation are continually debated, justifying comprehensive individualized risk assessment. Various promising techniques for further risk stratification are under evaluation, including cardiac magnetic resonance imaging, electrocardiographic assessment of electrical instability, and genetic testing. However, none of these strategies has been fully adapted into guidelines. Hence, clinical risk stratification practice today depends on LVEF and HF symptoms, which have poor sensitivity and specificity for predicting SCD risk.     

Long-term survival of patients with heart failure and ventricular conduction delay treated with cardiac resynchronization therapy

This multicenter longitudinal observational trial was designed to analyze the long-term outcome of patients with heart failure (HF) treated with cardiac resynchronization therapy (CRT) alone or with implantable cardioverter-defibrillator (ICD) backup in a daily practice scenario. It is unknown whether the magnitude of survival benefits conferred by CRT in a daily practice scenario is comparable to what has been observed in randomized controlled trials and whether this benefit is sustained over the long term. The outcome of 1,303 consecutive patients with ischemic or nonischemic cardiomyopathy on optimal pharmacologic therapy treated from August 1, 1995 to August 1, 2004 at 4 European centers with CRT alone (44%) or with ICD backup for symptomatic HF and prolonged QRS duration was assessed. Cumulative event-free survival was evaluated for a combined end point, defined as death from any cause, urgent transplantation, or implantation of a left ventricular assist device. The cumulative incidence of competing events, HF, sudden cardiac death, and noncardiac death, was also assessed. Event-free survival was similar across the different centers. At 1 and 5 years, cumulative event-free survivals were 92% (95% confidence interval [CI] 91 to 94) and 56% (95% CI 48 to 64), respectively. The cumulative incidence of HF deaths was 25.1% (95% CI 19 to 31.7), whereas that of sudden death was 9.5% (95% CI 5.1 to 15.7). Using multivariate analysis, CRT with an ICD backup was associated with a nonsignificant decrease in mortality by 20% (hazard ratio 0.83, 95% CI 0.58 to 1.17, p = 0.284), with a highly significant protective effect against sudden cardiac death (hazard ratio 0.04, 95% CI 0.04 to 0.28, p <0.002). In conclusion, patients with advanced HF and a wide QRS complex routinely treated with CRT have a favorable long-term outcome that was reproducible at different centers. The leading cause of death in these patients remained HF, and this mode of death was competing with other causes in determining outcome. Total mortality was 20% lower with ICD backup (95% CI 42% lower to 17% higher) due to a protective effect against sudden cardiac death.     

Effects of cardiac resynchronization therapy on overall mortality and mode of death: a meta-analysis of randomized controlled trials.

AIMS: Cardiac resynchronization therapy (CRT) has been shown to improve symptoms and exercise tolerance in patients with advanced heart failure (HF). However, studies were underpowered to address its effect on overall mortality. To evaluate whether CRT alone (without a combined defibrillator function) reduces overall mortality as compared with optimal pharmacological therapy, and how it affects the mode of death in patients with advanced HF. METHODS AND RESULTS: Public domain databases were systematically searched. Randomized controlled studies that evaluated the effects of CRT alone in patients with advanced HF and a depressed left ventricular systolic performance were selected for this analysis. Trials, which did not independently report data on CRT alone or had a follow-up period of less than 3 months, were excluded. Five studies were identified and analyzed. They included a total of 2371 patients, 1028 controls and 1343 CRT-treated patients. Pooled analysis demonstrated that CRT alone, as compared with optimal medical therapy, significantly reduced all-cause mortality by 29% [16.9 vs. 20.7%; odds ratio (OR), 0.71; 95% confidence interval (CI), 0.57-0.88] and mortality due to progressive HF by 38% (6.7 vs. 9.7%; OR, 0.62; 95% CI, 0.45-0.84). No effect on sudden cardiac death (SCD) was observed with CRT (6.4 vs. 5.9%; OR, 1.04; 95% CI, 0.73-1.22). CONCLUSIONS: CRT alone as compared with optimal medical therapy reduces all-cause mortality in patients with advanced HF. It predominantly reduces worsening HF mortality, not affecting SCD.     

Temporal Trends and Outcomes of Implantable Cardioverter Defibrillators in Heart Failure and Chronic Kidney Disease in the United States

Chronic kidney disease (CKD) and hemodialysis increase the risk of sudden cardiac death (SCD) in heart failure (HF); however, national trends in utilization and outcomes of implantable cardioverter-defibrillator (ICD) in this population remain unknown. We sought to evaluate the utilization and outcomes of ICD therapy in HF patients with CKD and end-stage renal disease (ESRD) using the National Inpatient Sample from 2009 to 2018. Hospitalizations with a discharge diagnosis of systolic HF and ICD implantation were identified and stratified by stages of kidney disease. A total of 281,219 systolic HF hospitalizations who underwent ICD implantation were included. A significant decrease in inpatient ICD implantation was observed over the past decade (3.7% in 2009 to 1.1% in 2018) regardless of renal impairment. In-hospital mortality was highest in ESRD, followed by CKD compared with patients with no CKD. Length of hospital stay and hospitalization costs were also significantly higher in patients with CKD and ESRD. The overall utilization of inpatient ICD implantation has decreased in systolic HF patients and inpatient ICD placement in CKD is associated with an increased risk of mortality and adverse clinical outcomes. This indicates that patients with renal impairment and HF represent a sicker cohort than the general HF population.     

Mode of death in advanced heart failure: the Comparison of Medical, Pacing, and Defibrillation Therapies in Heart Failure (COMPANION) trial.

OBJECTIVES: The aim of this study was to evaluate the mode of death in patients with advanced chronic heart failure (HF) and intraventricular conduction delay treated with optimal pharmacologic therapy (OPT) alone or OPT with biventricular pacing to provide cardiac resynchronization therapy (CRT) or CRT + an implantable defibrillator (CRT-D). BACKGROUND: Limited data are available on mode of death in advanced HF. No data have existed on mode of death in these patients who also have an intraventricular conduction delay and are treated with CRT or CRT-D. METHODS: Using prespecified definitions and source materials, seven cardiologists assessed mode of death among the 313 deaths that occurred in the Comparison of Medical, Pacing, and Defibrillation Therapies in Heart Failure (COMPANION) trial. RESULTS: A primary cardiac cause was present in 78% of deaths. Pump failure (44.4%) was the most common mode of death followed by sudden cardiac death (SCD) (26.5%). Compared with OPT, CRT-D significantly reduced the number of cardiac deaths (38%, p = 0.006), whereas CRT alone was associated with a non-significant 14.5% reduction (p = 0.33). Both CRT and CRT-D tended to reduce pump failure deaths (29%, p = 0.11 and 27%, p = 0.14, respectively). The CRT-D significantly reduced SCD (56%, p = 0.02), but CRT alone did not. CONCLUSIONS: Pump failure deaths are the predominant mode of death in patients with advanced HF and are modestly reduced by both CRT and CRT-D. Only CRT-D reduced SCD and thus produced a favorable effect on cardiac mortality.     

Reducing events in patients with chronic heart failure (REDUCEhf ) study design: continuous hemodynamic monitoring with an implantable defibrillator

BACKGROUND: The use of implantable cardioverter defibrillators (ICDs) has been proven effective in the prevention of sudden cardiac death (SCD) and constitutes standard of care in appropriate populations. Combining a pressure sensing system with ICD therapy represents the first attempt to provide continuous hemodynamic monitoring using a device previously designed exclusively for SCD protection. METHODS: REDUCE is a prospective, multicenter, randomized, single-blind, parallel-controlled trial designed to assess the safety of the Chronicle ICD system (single chamber ICD with a hemodynamic monitoring system) and the effectiveness of a management strategy guided by intracardiac pressure information among ICD-indicated New York Heart Association (NYHA) Class II or III heart failure (HF) patients. Those successfully implanted with a Chronicle ICD will be randomized to the Chronicle group or Control group. All patients will receive optimal medical therapy, but the hemodynamic information from the device will be used to guide patient management only in the Chronicle group. Primary endpoints include freedom from system-related complications and relative risk reduction of one or more HF-related events (hospitalizations, and emergency department and urgent care visits requiring intravenous therapy for HF). Approximately 850 patients will be enrolled in at least 75 centers in the United States to accrue the 419 events needed to test the primary effectiveness endpoint. Enrollment began in April 2006, and is expected to end during 2009. CONCLUSION: REDUCE will assess the safety of the Chronicle ICD system and the effectiveness of a patient management strategy based on remote access to continuous intracardiac pressures in reducing HF-related events.     

Sex-based differences in cardiac resynchronization therapy and implantable cardioverter defibrillator therapies: effectiveness and use

With the rapid advancements in heart failure device therapy, many physicians now use these devices in everyday clinical practice. However, questions remain regarding the clinical benefit of these therapies in different patient subgroups. Since the majority of patients enrolled in device trials are white men, extrapolating the data to specific patient subpopulations becomes important. Specifically, the question of clinical outcomes in women with implantable device therapy for prevention of sudden cardiac death and management of heart failure is an important clinical issue. In this article, we review the data on survival and clinical outcomes with heart failure device therapy (implantable cardioverter defibrillators [ICDs] and cardiac resynchronization therapy [CRT]) and analyze the results from clinical trials for any differences in outcomes based on gender. Even though women are a significantly under-represented population with regard to clinical investigation and utilization of heart failure devices, they still derive the same morbidity and mortality benefits compared to men. Specifically, ICD devices confer the same rates of sudden cardiac death prevention, and CRT devices improve CHF morbidity and mortality at rates comparable to those found in men. These results support equal use of ICDs and CRT in men and women.     

Impact of upgrade to cardiac resynchronization therapy on ventricular arrhythmia frequency in patients with implantable cardioverter-defibrillators.

OBJECTIVES: This study compared cardiac resynchronization therapy's (CRT) impact on ventricular tachyarrhythmia susceptibility in patients who, due to worsening heart failure (HF) symptoms, underwent a replacement of a conventional implantable cardioverter-defibrillator (ICD) with a CRT-ICD. BACKGROUND: Cardiac resynchronization therapy is an effective addition to conventional treatment of HF in many patients with left ventricular systolic dysfunction. However, whether CRT-induced improvements in HF status also reduce susceptibility to life-threatening arrhythmias is less certain. METHODS: Clinical and ICD electrogram data were evaluated in 18 consecutive ICD patients who underwent an upgrade to CRT-ICD. Pharmacologic HF therapy was not altered during follow-up. The definition of ventricular tachycardia (VT) and ventricular fibrillation (VF) for each patient was as determined by device programming. Statistical comparisons used paired t tests. RESULTS: Findings were recorded during two time periods: 47 +/- 21 months (range 24 to 70 months) before and 14 +/- 2 months (range 9 to 18 months) after CRT upgrade. At time of upgrade, patient age was 69 +/- 11 years and ejection fraction was 21 +/- 8%. Before CRT the frequency of VT, VF, and appropriate ICD shocks was 0.31 +/- 1.23, 0.047 +/- 0.083, and 0.048 +/- 0.085 episodes/month/patient, respectively. After CRT-ICD, VT and VF arrhythmia burdens and frequency of shocks were respectively 0.13 +/- 0.56, 0.001 +/- 0.004, and 0.003 +/- 0.016 episodes/month/patient (p = 0.59, 0.03, and 0.05 vs. pre-CRT). CONCLUSIONS: Arrhythmia frequency and number of appropriate ICD treatments were reduced after upgrade to CRT-ICD for HF treatment. Thus, apart from hemodynamic benefits, CRT may also ameliorate ventricular tachyarrhythmia susceptibility in HF patients.     

25?Jahre Defibrillatortherapie in Deutschland

The automatic cardioverter-defibrillator (ICD) was implanted for the first time in a human in Baltimore USA in 1980 and the first ICD implants in Germany were performed in January 1984. Sudden cardiac death (SCD) is one of the major problems in the western world with approximately 70,000-100,000 SCD patients in Germany and 450,000 in the USA. The ICD is the method of choice for primary or secondary prevention of SCD and still superior to all other therapeutic approaches 30 years after the first implant in the USA and 25 years after the first implants in Germany. Cardiac resynchronization therapy (CRT) is an important additional therapeutic tool and leads to improvements in congestive heart failure and overall survival. Telemonitoring is a promising concept and has substantially simplified the follow-up of ICD and CRT patients. Telemonitoring is safe, increases the quality of life for ICD and CRT patients and allows interaction between physician and patients. By utilizing this concept it is possible to guide patients safely, individually and effectively.