Cardiac Resynchronization Therapy for Heart Failure

n the current issue of Circulation, Anand and colleagues representing the COMPANION (The Comparison of Med- ical Therapy, Pacing and Defibrillation in Heart Failure) Investigators have brought forward compelling data that emphasize the substantial morbidity benefit of cardiac resyn- chronization therapy (CRT) in patients with moderately severe to severe heart failure. Unlike other studies that have reported reductions in heart failure hospitalizations, Anand et al have accounted for the competing risk of death and variations in follow-up time and surmised that CRT resulted in 44% (optimal pharmacological therapy plus CRT (CRT-P)) and 41% (optimal pharmacological therapy plus CRT with defibrillator (CRT-D)) reductions in heart failure- related hospitalizations. Remarkably, the benefit was seen within days to weeks and was a sustained effect throughout the trial.1 By our calculations using the reported heart failure hospital- ization rates (0.73 for optimal pharmacological therapy (OPT), 0.43 for CRT-D, and 0.41 for CRT-P), the number needed to treat with CRT to reduce 1 hospitalization is 4. This is a remarkable benefit for any evidence-based heart failure therapy. These data are sufficiently compelling that when aggregated with the known survival benefits ascribed to CRT, at least some of the residual concerns about efficacy for this device-based intervention should be assuaged. On the basis of these findings, the time may now have come to fundamentally change practice and to more avidly adhere to already extant class I indications for CRT in patients with class III or IV heart failure, with a prolonged QRS, and who are already on appropriate background medical therapy.2 Article p 969 Several early data sets established that a prolonged QRS is independently associated with worse outcomes in chronic heart failure. Recent analyses from the EVEREST (Efficacy of Vasopressin in Heart Failure Outcome Study with Tolvaptan) trials have confirmed a similar observation in the setting of acute decompensated heart failure. 3 The pathology