Implantable cardioverter defibrillators and quality of life: Results from the defibrillators in nonischemic cardiomyopathy treatment evaluation study

Background: The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study demonstrated that implantable cardioverter defibrillators (ICDs) significantly reduce the risk of sudden cardiac death in patients with nonischemic cardiomyopathy and an ejection fraction of 35% or less, with no statistically significant decrease in overall mortality. The impact of ICD placement and shock on health-related quality of life (HRQL) in this population is unknown. Methods: The 12-Item Medical Outcomes Short-Form Health Survey and the Minnesota Living with Heart Failure Questionnaire were administered to 458 patients with nonischemic cardiomyopathy, an ejection fraction of 35% or less, and either nonsustained ventricular tachycardia or 10 or more premature ventricular depolarizations per hour at baseline, 1 month after randomization, and every 3 months thereafter throughout the trial. The subjects were randomized toan ICD or standard medical therapy. Outcomes were compared using hierarchical linear regression. Results: Overall, there were no significant differences in HRQL throughout the trial between patients randomized to an ICD or standard medical therapy. However, in patients with 1 or more ICD shocks, HRQL declined 0.5±0.2 (mean±SD) points per shock on the emotional scale of the Minnesota Living with Heart Failure Questionnaire (P=.04) and 1.0±0.5 points per shock on the mental component score of the 12-Item Medical Outcomes Short-Form Health Survey (P=.04). Conclusions: Overall, HRQL was not affected by ICD implantation in patients in the Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study. Implantable cardioverter defibrillator shock was associated with a reduction in some measures of HRQL, but the effects were unlikely to result in a clinically observable alteration until 5 or more shocks were experienced.