Differences in Tachyarrhythmia Detection and Implantable Cardioverter Defibrillator Therapy by Primary or Secondary Prevention Indication in Cardiac Resynchronization Therapy Patients

INTRODUCTION: Although numerous trials have shown benefit of implantable cardioverter defibrillators (ICDs) for either primary or secondary prevention, no trial has prospectively enrolled patients from both indications and analyzed ICD utilization between groups. METHODS AND RESULTS: We performed a retrospective review of MIRACLE ICD, a randomized, prospective double-blind trial of cardiac resynchronization therapy (CRT) in the ICD population. Both secondary prevention (N = 563) and primary prevention patients (N = 415) were enrolled. Subgroup analysis for frequency of ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes and detection accuracy revealed that primary prevention patients had a…