Death Without Prior Appropriate Implantable Cardioverter-Defibrillator Therapy

Abstract

Background-Implantable cardioverter-defibrillators (ICDs) improve survival in selected patients with left ventricular systolic dysfunction in randomized trials. Competing death without prior appropriate ICD therapy might preclude benefit from ICD implantation in a less selected routine-care population. Methods and Results-We selected all patients with ischemic or dilated cardiomyopathy with an ICD implanted for primary or secondary prevention from a single-center prospective registry between 1994 and 2006. The end point was time to first appropriate ICD therapy/confirmed ventricular fibrillation or death without prior appropriate ICD therapy. We analyzed cumulative incidence functions and used competing risk regression to study predictors of appropriate ICD therapy or prior death. In 442 patients, 73 deaths occurred during a median follow-up of 3.6 years (maximum, 12.7 years). The cumulative incidence of first appropriate ICD therapy until year 7 was 52%, whereas 11% died without prior ICD therapy. The cumulative incidence of appropriate ICD therapy for ventricular fibrillation was 13%, whereas 23% died without prior therapy for ventricular fibrillation. Appropriate ICD therapy was twice as likely in secondary prevention compared with primary prevention, whereas death rates before ICD therapy were similar in both groups. Diuretic use for heart failure compared with nonuse predicted a 4-fold-increased risk of death prior to ICD therapy, although the incidence of appropriate ICD therapy was similar in both groups. Conclusion-In a contemporary ICD population, the risk of death without prior appropriate ICD therapy is substantial, especially in patients with advanced heart failure.

CORR Insights®: Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis

“…In light of this, alternative analytic approaches that account for the occurrence of such competing events have been developed to estimate the cumulative incidence [1,8]. While these issues are mathematically demonstrated and have been illustrated in various medical domains [2,3,6], they have received less attention in orthopaedic research until recently [7,8]. But while some work has been done in individual datasets [8], to my knowledge, no study has taken a broader look at the influence of the phenomenon of competing risks on Kaplan-Meier survivorship estimates across orthopaedics more generally.…”

“…Two types of analyses can be carried out, both being methodologically correct, but with different aims and sometimes different results. Indeed, one could assess whether the cumulative incidence of revision is higher with one type of implant as compared to another, or whether the cause-specific hazard of revision-the instantaneous rate of revision among the patients still alive with their implant-is higher with the first type of implant as compared to the other [3]. In the classical survival setting where patients can only fail from one cause (overall survival analysis), both analyses are equivalent, and are commonly carried out using a Cox proportional hazards model.…”

Implantable Cardioverter-Defibrillators in Sudden Cardiac Death Prevention: What Guidelines Don't Tell

“…The majority of patients who died prior to appropriate ICD therapy had a primary prevention indication. Despite the effectiveness of terminating ventricular tachyarrhythmias by the ICD, competing non-cardiac comorbidity is associated with increased mortality [75]. Furthermore the effect of renal function on ICD efficacy was assessed in a retrospective analysis from MADIT II [76].…”

Prognostic Importance of Defibrillator Shocks in Survivors of Sudden Cardiac Death

“…In particular, the mechanical stress due to the electrical conversion therapy received before, would have caused an additional insult to the underlying myocardium. This could act as a potential substrate predisposing the patient for further serious ventricular tachyarrhythmia [16]. Despite this increased risk of malignant arrhythmias, there was no increased mortality in ICD recipients who Prior case series have shown that many SVT can progress to VT/VF causing SCD [17].…”