Survival Benefit Of Implantable Cardioverter-defibrillator Research Articles

INCREASED DISPERSION OF ATRIAL REFRACTORINESS PREDICTS MOST OF THE INAPPROPRIATE IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR SHOCKS

Background and aim: Despite the proven survival benefits of implantable cardioverter-defibrillators, inappropriate shocks limits their benefits due to adverse effects on quality of life, potential arrhythmogenesis an deven on mortality. Atrial fibrillation (AF) is the most common cause of inappropriate shocks. Therefore, to predict and treat AF may prevent inappropriate shocks and their hazardous potentials. This paper aimed to show that by measuring atrial refractoriness, we could predict the patients who may experience inappropriate implantable cardioverter-defibrillator shocks.\n Material and methods: 186 consecutive patients who underwent initial ICD implantation underwent coronary angiography and also underwent electrophysiologic (EP) study before the ICD implantation. \nResults: Of 169 patients who could be followed, 34 received (20%) at least 1 inappropriate shocks during the mean follow-up of 30 months. Majority of these shocks were due to AF (68%). Atrial effective refactory periods (AERPs) and AERP dispersion were the most significant predictors for these inappropriate shocks. \nConclusion: We found that simple EP study parameters measuring atrial refractoriness may define the patients carrying higher risk for future inappropriate shocks due to AF. In these patients, by either device programming or pharmocological treatments or ablation procedures, we could prevent inappropriate shocks and their hazardous results.

Centers for Medicare and Medicaid Services' Decision to Reconsider Coverage Indications for ICDs: Where to Now?

Several well-designed and conducted randomized clinical trials (RCTs) have proven the survival benefit of implantable cardioverter defibrillators (ICDs). This benefit has been demonstrated in patients who survive a cardiac arrest due to a ventricular tachyarrhythmia or have sustained ventricular tachycardia not due to a transient or a reversible cause. The survival benefit of ICDs has also been shown in patients with significant systolic dysfunction (left ventricular ejection fraction (LVEF) ≤35%) due to ischemic or non-ischemic cardiomyopathy. The compelling evidence on the benefits of ICDs led the Centers for Medicare and Medicaid services (CMS) to cover secondary and primary prevention ICDs in Medicare beneficiaries. However, for primary prevention ICDs, CMS provides coverage with evidence development that requires clinicians to enter data on primary prevention ICD implants in Medicare beneficiaries into the National Cardiovascular Data Registry (NCDR) ICD Registry.

Implantable cardioverter-defibrillators in end-stage heart failure patients listed for heart transplantation: Results from a large retrospective registry

Implantable cardioverter-defibrillators (ICDs) are recommended in patients with low ejection fraction. However, the survival benefit of ICDs in patients with end-stage heart failure listed for heart transplantation is unclear. To evaluate the ICD benefit on mortality in this population. Three hundred and eighty consecutive patients listed for heart transplantation between 2005 and 2009 in one tertiary heart transplant centre were enrolled in a retrospective registry; 122 patients received an ICD before or within 3 months after being listed for heart transplantation (ICD group). Predictors of death on the waiting list were assessed by Cox regression. Overall, 15.6% of patients died while awaiting heart transplantation. Non-ICD patients presented more often haemodynamic compromise requiring mechanical circulatory support (29.1% vs. 9.8%; P<0.001), and were more likely to die while on the waiting list (19.0% vs. 8.3%; log-rank P=0.001). However, in the multivariable model, ICD did not remain an independent predictor of death. Need for mechanical circulatory support (P<0.001), low ejection fraction (P=0.001) and registration on the regular list (P=0.008) were the only independent predictors of death. Death was mainly caused by haemodynamic compromise (76.3% of deaths), which occurred more frequently in the non-ICD group (14.7% vs. 5.8%; log-rank P=0.002). Unknown/arrhythmic deaths did not differ significantly between the two groups (3.9% vs. 1.7%; log-rank P=0.21). ICD-related complications occurred in 21.4% of patients, mainly as a result of postoperative worsening of heart failure (11.9%). Haemodynamic failure appears as the main determinant of mortality in patients with end-stage heart failure awaiting heart transplantation. ICD seems to have little benefit on survival in this population.

0494: Do implantable cardioverter defibrillators really improve survival of patients listed for heart transplantation?

Implantable cardioverter defibrillators (ICD) are recommended in patients with low ejection fraction. However the survival benefit of ICD in patients with end-stage heart failure listed for heart transplantation is unclear. The objective was to evaluate the ICD benefit on mortality in this population. 380 consecutive patients listed for heart transplantation between 2005 and 2009 in one tertiary heart transplant center were enrolled in a retrospective registry. 122 patients received an ICD before or within 3 months after registry (ICD-group). Predictors of death in the waiting list were assessed by Cox regression. 15.6% of patients died while awaiting heart transplantation. NonICD patients presented more often haemodynamic compromise requiring mechanical circulatory support (MCS, 34.2% vs 14.9%, p<0.0001) and were more likely to die while in the waiting list (19.0% vs 8.3%, p=0.006). However, in the multivariate model, ICD did not remain an independent predictor of death. The need for a MCS and LVEF were the only independent predictors of death (p<0.0001 and p=0.001). Death was mainly due to haemodynamic compromise (76.6% of deaths), which occurred more frequently in the non-ICD group (14.7% vs 5.8%, p=0.019). Unknown/arrhythmic deaths did not significantly differ between the two groups (3.9% vs 1.7%, p=0.19). ICD-related complications occurred in 21.4% of patients, mainly due post-operative worsening of heart failure (11.9%). Haemodynamic failure appears as the main determinant of mortality in patients awaiting heart transplantation. ICD seems to have little benefit on survival in this population.

Attitudes of older adults with serious competing health risks toward their implantable cardioverter-defibrillators: a pilot study.

BackgroundIn elderly heart failure patients, the survival benefit of implantable cardioverter-defibrillators (ICDs) may be attenuated due to competing health risks, and the risk of adverse outcomes magnified. Our objective was to examine older adults’ attitudes towards ICD implantation in the context of competing health risks, exploring the determinants of ICD decision-making among a group of patients who had faced the decision in the past.MethodsTelephone survey with a qualitative component. Patients were age ≥70 with single- or dual-chamber ICDs from a single academic cardiac device clinic. Health status was assessed with the Vulnerable Elders Survey (VES-13). Responses to open-ended questions were transcribed verbatim; an “editing analysis” approach was used to extract themes.ResultsForty-four ICD recipients participated (mean age 77.5 years). Nineteen participants (43 %) had VES-13 scores ≥3, indicating a 50 % likelihood of death or functional decline within 2 years. Twenty-one participants (48 %) had received prior ICD shocks. Forty participants (91 %) said they would “definitely” choose to get an ICD again in their current health. By and large, patients revealed a strong desire to extend life, expressed complete confidence in the lifesaving capabilities of their ICDs, and did not describe consideration of competing health risks.ConclusionsIn this pilot telephone survey with a qualitative component, nearly all older adults with ICDs would still choose to get an ICD despite high short-term risk of death or health deterioration. These findings suggest the need to partner more effectively with patients and families to decide how best to use medical technologies, particularly for older adults with competing risks.

Implantable Cardioverter-Defibrillator Use in Older Adults: Proceedings of a Hartford Change AGEnts Symposium.

Since their initial clinical demonstration in 1980, implantable cardioverter–defibrillators (ICDs) have prolonged countless lives with successful treatment of sudden cardiac arrest.1 No other therapy has proved as effective in preventing death from ventricular arrhythmias, and important advances in ICD technology continue to improve outcomes for well-selected patients.2 Although indicated for a wide range of inherited and acquired conditions,3 ICDs are predominantly placed in older patients with left ventricular systolic dysfunction and either previous myocardial infarction or congestive heart failure.4 In the United States alone, >50 000 ICDs are placed annually in patients aged > 65 years, and nearly 500 000 more may meet current guidelines for device implantation.5 However, decision making for older patients considering ICD implantation is particularly challenging. Subjects in the landmark trials had average ages in the 60s, and thus the survival benefits of ICDs in older age groups is less well-established.6 In addition, compared with the younger participants in most clinical trials, older adults have a lower ratio of arrhythmic death to nonarrhythmic death because of competing risks for mortality, resulting in a potentially lower absolute risk reduction. At the same time, living and eventually dying with an ICD introduces potential risks, including a lower quality of life (QoL), hospitalizations, and potential suffering at the end of life.7 A rigorous consideration of the benefits, risks, and ongoing care surrounding ICD use in older patients is long overdue. On April 22, 2014, we convened a conference of multidisciplinary experts in cardiac electrophysiology, heart failure, geriatrics, ethics, and palliative care in Boston, supported by the Hartford Change AGEnts and Paul B. Beeson Career Development Award programs, and the Hebrew SeniorLife Institute for Aging Research. The objectives of the conference were (1) to review what is currently known about ICD use in …

Abstract 17276: Implantable Cardioverter-Defibrillator Therapy in Women: Population-based Outomes

Background: Due to the low enrolment of women in implantable cardioverter-defibrillator (ICD) trials, there is controversy whether the survival benefit of ICDs applies to both sexes. Population-based data examining sex differences in ICD outcomes may provide further clarification. Methods: Study data were derived from a provincial registry in British Columbia (BC), the Cardiac Services BC Registry, where all ICD recipients are recorded. Patients ≥18 years with a new ICD implant from Jan 2003 to Dec 2012 were included. Data were linked to BC Vital Statistics to determine all-cause mortality. Survival was assessed using Kaplan-Meier methods stratified by sex and compared using the log-rank test. The Cox proportional-hazards model was used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) between sexes. The effect of demographics, comorbidities and medication use were explored and only factors with a p-value &lt; 0.15 were included in the final model. Statistical analyses were performed with SAS software, version 9.3 (Cary, NC). Results: There were 3905 new ICD implants; of these, 704 were women (18%). Women were younger and had a lower prevalence of comorbidities. Except for beta-blockers, women were less likely to be prescribed cardiac medications. The overall survival of women was greater than men; however, women had a higher re-operation rate for complications (Figure). After adjusting for age, diabetes, coronary artery disease, congestive cardiomyopathy, peripheral vascular disease, acquired heart surgery, and anti-arrhythmic drug use, the sex difference in mortality was attenuated, adjusted HR 0.91, (95% CI: 0.75,1.12). Conclusions: Women may derive the same survival benefit as men but have a higher re-operation rate for complications. Ongoing analyses will determine whether the impact of sex on mortality differs among patients receiving an ICD for primary versus secondary prevention.

POPULATION-BASED OUTCOMES OF ICD THERAPY IN WOMEN

Although randomized controlled trials have established the survival benefit of implantable cardioverter-defibrillators (ICDs) in the prevention of sudden cardiac death, controversy remains as to whether this benefit applies equally to women and men. Due to the low enrolment of women in the ICD trials, population-based data examining sex differences in ICD outcomes may provide further clarification. Study data were derived from a provincial registry in British Columbia (BC) - the Cardiac Services BC Registry. All recipients of an ICD in BC are recorded in the Registry. Patients ≥18 years with a new ICD implant from Jan 2003 to Dec 2012 were included and linked with data from BC Vital Statistics to determine all-cause mortality. Survival was assessed using Kaplan-Meier (KM) methods stratified by sex and compared using the log-rank test. The Cox proportional-hazards model was used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) between sexes. The effects of baseline characteristics (demographics, comorbidities and medication use) were explored and only factors with a p-value < 0.15 were included in the final adjusted model. Statistical analyses were performed using SAS software, version 9.3 (Cary, NC). During the study period, 3905 new ICD implants were performed. Of these, 704 (18%) were women. Women in the cohort, compared to men, were younger (59.6 vs. 63.5 years), respectively, and had a lower prevalence of comorbid conditions (Table). Except for beta-blocker use, women were less likely to be prescribed cardiac medications such as ACE inhibitors and anti-arrhythmics. The KM survival estimates were 0.95 at 1-year for both sexes, 0.79 for women and 0.73 for men at 5 years, and 0.70 for women and 0.57 for men at 8 years; the overall survival of women was greater than men (Figure). After adjusting for age, diabetes, coronary artery disease, congestive cardiomyopathy, peripheral vascular disease, acquired heart surgery, and anti-arrhythmic drug use, in the Cox proportional-hazards model, the sex difference in mortality was attenuated and no longer significant, adjusted HR 0.91, (95% CI: 0.75,1.12). Mortality trends from our population reveal that there is no difference in survival between women and men with ICDs. This may imply that women with ICDs derive the same benefit as men. Ongoing analyses will determine whether the impact of sex on mortality is different among patients receiving an ICD for primary versus secondary prevention and among those with ICDs compared to a similar population without ICDs.View Large Image Figure ViewerDownload (PPT)

Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death in CKD: A Meta-analysis of Patient-Level Data From 3 Randomized Trials

The benefit of a primary prevention implantable cardioverter-defibrillator (ICD) among patients with chronic kidney disease is uncertain. Meta-analysis of patient-level data from randomized controlled trials. Patients with symptomatic heart failure and left ventricular ejection fraction<35%. From 7 available randomized controlled studies with patient-level data, we selected studies with available data for important covariates. Studies without patient-level data for baseline estimated glomerular filtration rate (eGFR) were excluded. Primary prevention ICD versus usual care effect modification by eGFR. Mortality, rehospitalizations, and effect modification by eGFR. We included data from the Multicenter Automatic Defibrillator Implantation Trial I (MADIT-I), MADIT-II, and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT). 2,867 patients were included; 36.3% had eGFR<60 mL/min/1.73m2. Kaplan-Meier estimate of the probability of death during follow-up was 43.3% for 1,334 patients receiving usual care and 35.8% for 1,533 ICD recipients. After adjustment for baseline differences, there was evidence that the survival benefit of ICDs in comparison to usual care depends on eGFR (posterior probability for null interaction P<0.001). The ICD was associated with survival benefit for patients with eGFR≥60 mL/min/1.73 m2 (adjusted HR, 0.49; 95% posterior credible interval, 0.24-0.95), but not for patients with eGFR<60 mL/min/1.73 m2 (adjusted HR, 0.80; 95% posterior credible interval, 0.40-1.53). eGFR did not modify the association between the ICD and rehospitalizations. Few patients with eGFR<30 mL/min/1.73 m2 were available. Differences in trial-to-trial measurement techniques may lead to residual confounding. Reductions in baseline eGFR decrease the survival benefit associated with the ICD. These findings should be confirmed by additional studies specifically targeting patients with varying eGFRs.

Implantable cardioverter-defibrillators for treatment of sustained ventricular arrhythmias in patients with Chagas' heart disease: comparison with a control group treated with amiodarone alone

Evidence is inconclusive concerning the benefit of implantable cardioverter-defibrillators (ICDs) for secondary prevention of mortality in patients with Chagas' heart disease (ChHD). The aim of this study was to compare the outcomes of ChHD patients with life-threatening ventricular arrhythmias (VAs), who were treated either with ICD implantation plus amiodarone or with amiodarone alone. The ICD group [76 patients; 48 men; age, 57 ± 11 years; left ventricular ejection fraction (LVEF), 39 ± 12%] and the historical control group treated with amiodarone alone (28 patients; 18 men; age, 54 ± 10 years; LVEF, 41 ± 10%) had comparable baseline characteristics, except for a higher use of beta-blockers in the ICD group (P < 0.0001). Amiodarone was also used in 90% of the ICD group. Therapy with ICD plus amiodarone resulted in a 72% reduced risk of all-cause mortality (P = 0.007) and a 95% reduced risk of sudden death (P = 0.006) compared with amiodarone-only therapy. The survival benefit of ICD was greatest in patients with LVEF < 40% (P = 0.01) and was not significant in those with LVEF ≥ 40% (P = 0.15). Appropriate ICD therapies occurred in 72% of patients and the rates of interventions were similar across patients with LVEF < 40% and ≥40%. Compared with amiodarone-only therapy, ICD implantation plus amiodarone reduced the risk of all-cause mortality and sudden death in ChHD patients with life-threatening VAs. Patients with LVEF < 40% derived significantly more survival benefit from ICD therapy. The majority of ICD-treated patients received appropriate therapies regardless of the LV systolic function.

Effect of left ventricular ejection fraction and QRS duration on the survival benefit of implantable cardioverter-defibrillators: Meta-analysis of primary prevention trials

Implantable cardioverter-defibrillators (ICDs) are recommended for the primary prevention of sudden cardiac death in patients with left ventricular dysfunction, but it is unclear whether treatment benefits are diminished in patients with very low baseline left ventricular ejection fraction (LVEF) (<25%) or increased in those with prolonged QRS duration (>120 ms). To study the effects of very low LVEF and prolonged QRS duration on the mortality benefits of ICD therapy. We performed a meta-analysis of primary prevention randomized controlled trials comparing ICD and standard medical therapy. All-cause mortality hazard ratios (HRs) in subgroups according to thresholds of 25% for LVEF and 120 ms for QRS duration were extracted from published reports or contributed by trial investigators and synthesized. There was no significant difference of ICD effectiveness in LVEF subgroups of 25%-35% (random effects HR 0.81; 95% confidence interval [CI] 0.70-0.94) vs<25% (HR 0.71; 95% CI 0.55-0.93). Results were also similar in the narrow and wide QRS subgroups (HR 0.78; 95% CI 0.68-0.90 and HR 0.70; 95% CI 0.51-0.95, respectively). Within the LVEF<25% and wide QRS subgroups, there was large heterogeneity driven by the Defibrillator in Acute Myocardial Infarction Trial that included patients with early post-myocardial infarction and its results (HR 1.49; 95% CI 0.84-2.68 and HR 1.51; 95% CI 0.83-2.83, respectively) differed significantly from other trials (P = .008 and P = .01, respectively). LVEF values and QRS duration do not appear to directly modify the survival benefit of ICD in patients with baseline LVEF<35%. However, patients with a recent myocardial infarction do not benefit from ICD, especially when they have LVEF<25% and/or wide QRS.

Out-of-the-Box ICD Programming Is History

The well-established survival benefits of implantable cardioverter-defibrillators (ICDs) can be tempered by the delivery of sometimes inappropriate shocks. To evaluate programming strategies for mitigating such shocks, researchers conducted a trial, funded by an ICD manufacturer, in which 1500 patients with a primary indication for an ICD were randomized to one of three programming configurations:

Survival Benefit of Implantable Cardioverter-Defibrillators in Left Ventricular Assist Device–Supported Heart Failure Patients

BackgroundImplantable cardioverter-defibrillators (ICDs) reduce mortality in heart failure (HF). In patients requiring a ventricular assist device (VAD), the benefit from ICD therapy is not well established. The aim of this study was to define the impact of ICD on outcomes in VAD-supported patients. Methods and ResultsWe reviewed data for consecutive adult HF patients receiving VAD as a bridge to transplantation from 1996 to 2003. The primary outcome was survival to transplantation. A total of 144 VADs were implanted [85 left ventricular (LVAD), 59 biventricular (BIVAD), mean age 50 ± 12 years, 77% male, left ventricular ejection fraction 18 ± 9%, 54% ischemic]. Mean length of support was 119 days (range 1–670); 103 patients (72%) survived to transplantation. Forty-five patients had an ICD (33 LVAD, 12 BIVAD). More LVAD patients had an appropriate ICD shock before implantation than after (16 vs 7; P = .02). There was a trend toward higher shock frequency before LVAD implant than after (3.3 ± 5.2 vs 1.1 ± 3.8 shocks/y; P = .06). Mean time to first shock after VAD implant was 129 ± 109 days. LVAD-supported patients with an ICD were significantly more likely to survive to transplantation [1-y actuarial survival to transplantation: LVAD: 91% with ICD vs 57% without ICD (log-rank P = .01); BIVAD: 54% vs 47% (log-rank P = NS)]. An ICD was associated with significantly increased survival in a multivariate model controlling for confounding variables (odds ratio 2.54, 95% confidence interval 1.04–6.21; P = .04). ConclusionsShock frequency decreases after VAD implantation, likely owing to ventricular unloading, but appropriate ICD shocks still occur in 21% of patients. An ICD is associated with improved survival in LVAD-supported HF patients.

Does Cardiac Resynchronization Therapy Prevent Heart Failure?

Device therapy for heart failure has become a wellestablished treatment for moderate to severely symptomatic heart failure through improved symptoms, exercise capacity, reverse remodeling, and morbidity with cardiac resynchronization therapy (CRT) [1–3]. The survival benefit of implantable cardioverter-defibrillators (ICD) has been well documented in clinical trials in patients with mild to moderate symptoms [4, 5], and CRT without an ICD also improved survival in more advanced patients, New York Heart Association (NYHA) class III or ambulatory class IV heart failure [3]. More recently, CRT studies have shown a reduction in heart failure hospitalization and improved left ventricular (LV) function and dimensions in milder heart failure (NYHA class I and II), primarily for QRS duration over 150 ms [6, 7]; however, no mortality difference was found with the addition of CRT in this milder heart failure population.