Background: Although pharmacological therapy has ameliorated symptoms and improved the survival of patients with chronic heart failure (CHF), this chronic syndrome remains a progressive disease causing incremental morbidity and early mortality. A new therapy for the treatment of CHF should ideally decrease mortality, alleviate symptoms, and improve functional capacity. A growing body of evidence suggests that the use of implantable devices to resynchronize ventricular contraction may be a beneficial adjunct in the treatment of CHF.
Methods: The Comparison of Medical Therapy, Pacing, and Defibrillation in Chronic Heart Failure (COMPANION) trial is a randomized, open-label, 3-arm study of patients in New York Heart Association class III or IV with an ejection fraction of 35% or less and a QRS duration of 120 milliseconds or less. The COMPANION study objectives are to determine whether optimal pharmacological therapy used with (1) ventricular resynchronization therapy alone or (2) ventricular resynchronization therapy combined with cardioverter-defibrillator capability is superior to optimal pharmacological therapy alone in reducing combined all-cause mortality and hospitalizations; reducing cardiac morbidity; improving functional capacity, cardiac performance, and quality of life; and increasing total survival.