Predictors of Sudden Cardiac Death and Appropriate Shock in the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) Trial

Background— The factors that determine the risk for sudden death or implantable cardioverter defibrillator therapy in patients receiving cardiac resynchronization therapy (CRT) therapies are largely unknown. Methods and Results— We hypothesized that clinical measures of heart failure severity and the presence of comorbid conditions would predict the risk of malignant arrhythmias in the 1520 patients enrolled in the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) Trial. Outcomes in the CRT group after implantable cardioverter defibrillator therapy were also evaluated. The CRT-defibrillator device reduced the risk of sudden death by 56% compared with drug therapy (17 of 595 [2.9%] versus 18 of 308 [5.8%], P 20% (HR, 0.55 [95% CI, 0.35 to 0.87]; P=0.01), QRS duration >160 ms (HR, 0.63 ...