The Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial in perspective.

The Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial is one of several randomized trials that has demonstrated an improvement in morbidity and mortality with biventricular pacemakers and/or implantable defibrillators. Although the results of the COMPANION trial overlap with other trials investigating cardiac resynchronization therapy (CRT) and implantable cardioverter-defibrillators (ICDs), there are several unique aspects of the trial that warrant special attention. This review focuses on COMPANION in light of other CRT trials, and includes a discussion on the patient population enrolled, design challenges of the trial, the cost-effectiveness of CRT and CRT-D, and results of subanalyses using data collected during the trial.