Perspective:

Randomized controlled trials have shown reduced morbidity and mortality with both CRT-P and CRT with ICD (CRT-D). However, increasing age, peripheral vascular disease, diabetes, and chronic kidney disease likely attenuate the survival benefit of ICD therapy. In a prior study involving patient-level data from four major randomized trials of primary prevention ICD, the presence of >3 comorbidities nullified the survival benefit associated with ICD implant (Steinberg BA, et al., JACC Heart Fail 2014;2:623-9). In patients undergoing CRT implant, the addition of ICD therapy has implications in terms of device complications, inappropriate device therapy, higher rate of generator change associated with battery depletion, and ultimately cost-effectiveness. In the present study, the predictors of CRT-D implantation included demographic, clinical, and nonclinical factors. This study does not directly address issues of CRT-D vs. CRT-P efficacy, but compels us to consider the optimal device selection in the cohort of patients who have been grossly under-represented in clinical trials of both ICD and CRT therapy.