The Mode of Death in Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy With Defibrillator Patients: Results From Routine Clinical Practice

Study Questions:

What is the mode of death in patients undergoing implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy (CRT) in clinical practice?


This was a retrospective analysis of a single-center prospectively collected database of all patients undergoing ICD and/or CRT-defibrillator (CRT-D) therapy at Leiden University Medical Center for primary and secondary prevention according to guidelines. Cause of death was categorized as cardiac death, noncardiac death, and sudden death.


There were 2,859 patients undergoing device implant who were followed a median 3.4 years. Patients in the CRT-D group were older with lower ejection fractions. Cumulative mortality over 2, 4, and 8 years was 10%, 20%, and 39.9%, respectively. Mortality in the primary prevention group was 14% (n = 107), and 35% (n = 37) of these patients died of heart failure, 7% (n = 7) of sudden death, and 33% (n = 35) of noncardiac causes. Mortality in the secondary prevention group was 28% (n = 253), with 28% (n = 71) of deaths due to heart failure and 38% (n = 95) from noncardiac causes. In the CRT-D group, 25% (n = 302) of patients died. Heart failure was the mode of death in 43% (n = 131) and 30% (n = 92) died of noncardiac causes. Overall, the 8-year cumulative incidence (95% confidence interval) of death from heart failure was 8.6% (7.1-12%) in the primary prevention group, 9.6% (7.1-12%) in the secondary prevention group, and 22.6% in the CRT-D group. Sudden death occurred in 7% (n = 49) of patients with an 8-year cumulative incidence of 2.1% (0.3-4.0%), 3.2% (1.6-4.8%), and 3.6% (1.8-5.3%) in the primary, secondary, and CRT-D groups, respectively.


The authors concluded that most patients undergoing ICD or CRT-D implant die of heart failure or noncardiac causes.


The authors demonstrated that patients in a clinical setting have lower annual mortality rates in general and lower heart failure mortality rates than those enrolled into major clinical trials of ICD and CRT-D therapy. While patients undergoing ICD implant for secondary prevention had higher ejection fractions at baseline, they had a rate of heart failure death similar to that of patients undergoing device implant for primary prevention. The CRT-D group had the worst outcomes, but also had sicker clinical characteristics at baseline (e.g., older age, lower ejection fraction, worse renal function).

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Heart Diseases, Cause of Death, Incidence, Defibrillators, Cardiac Pacing, Artificial, Heart Failure, Death, Sudden, Cardiac, Defibrillators, Implantable, Primary Prevention, Cardiac Resynchronization Therapy

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