COMPANION and DEFINITE Add More Fuel to the Heart Failure Debate

The Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) study enrolled a total of 1,520 patients with New York Heart Association (NYHA) heart failure classifications III or IV, having ischemic or nonischemic cardiomyopathies, with a QRS width of at least 120 msec and an ejection fraction (EF) of 0.35 or less. The study hypothesis asked the question of whether prophylactic cardiac-resynchronization therapy with pacemaker or with pacemaker and ICD would reduce the risk of death and rate of hospitalization in patients with advanced heart failure. Subjects in this multicenter trial were randomized in a 1:2:2 fashion to optimal drug therapy, drug therapy plus resynchronization, or drug therapy plus resynchronization plus ICD. The optimal pharmacologic therapy as defined in this study included use of diuretics, angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers, beta-blockers and spironolactone. Use of other medications was at the physician s discretion. The group randomized to cardiac resynchronization therapy received the Contak TR model 1241 pacemaker by Guidant, and those receiving the pacemaker-defibrillator combination had the Contak CD model 1823 by Guidant implanted. Study endpoints were: 1) primary endpoint: a composite of death from any cause or hospitalization for any cause; and 2) secondary endpoint: death from any cause. The Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial hypothesized that ICD therapy would reduce the risk of death in patients with nonischemic cardiomyopathy and moderate-to-severe left ventricular dysfunction. This was a multicenter study in which patients were randomized 1:1 to optimal medical therapy versus optimal medical therapy plus ICD (single chamber St. Jude Medical ICD).