Implantable Defibrillators Improve Survival in Mildly Symptomatic Heart Failure Patients Receiving Cardiac Resynchronization Therapy: Analysis of the Long-Term Follow-Up of REVERSE

Study Questions:

What are the clinical outcomes and long-term survival among cardiac resynchronization therapy (CRT) patients with and without implantable cardioverter-defibrillators (ICDs)?


REVERSE was a multicenter, randomized trial of CRT among patients with mild heart failure (HF). All patients underwent implantation of a CRT system (device and leads), with or without ICD capabilities, based on standard clinical criteria at the time of enrollment. Long-term annual follow-up for 5 years was preplanned. Patients who underwent successful implantation (n = 610) were randomly assigned in a 2:1 fashion to active CRT (CRT ON) or to a control group (CRT OFF).The present analysis was confined to the 419 patients who were randomized to CRT ON.


CRT pacemakers (CRT-P) or devices with defibrillator back-up (CRT-D) were implanted based on national guidelines at the time of enrollment, with 74 patients receiving CRT-P devices and the remaining 345 receiving CRT-D devices. After 12 months of CRT, changes in the Clinical Composite Score, left ventricular end-systolic volume index (LVESVi), 6-minute walk time, and quality-of-life indices were similar between CRT-P and CRT-D patients. However, long-term follow-up showed lower mortality in the CRT-D group. Specifically, multivariable analysis showed that CRT-D (hazard ratio, 0.35; p = 0.003) was a strong independent predictor of survival. Female sex, longer unpaced QRS duration, and smaller baseline LVESVi were also associated with better survival.


The authors concluded that the addition of ICD therapy to CRT is associated with improved long-term survival compared with CRT pacing alone in mild HF.


This post-hoc subgroup analysis from the REVERSE trial suggests that the addition of ICD therapy to CRT (CRT-D) reduces long-term mortality compared with CRT pacing alone. Multivariable analysis demonstrated a highly significant 65% reduction of mortality rates with CRT-D during the 5-year follow-up. The study findings appear to suggest that CRT-D devices should be considered in mild HF patients; particularly those with good long-term life expectancy, but additional prospective validation of these findings are indicated.

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

Keywords: Defibrillators, Cardiac Resynchronization Therapy, Heart Diseases, Survivors, Walking, Cardiac Pacing, Artificial, Ventricular Remodeling, Heart Failure, Stroke Volume, Ventricular Dysfunction, Left, Pregnancy, Defibrillators, Implantable, Death, Sudden, Cardiac

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