Results
Predictors of increased risk for ventricular arrhythmia and risk score
A best-subset regression analysis in the CRT-D arm of the trial identified 4 factors (from the 29 candidate covariates listed in Table A in the online-only data supplement) as being associated with increased risk for VTA (eTable B). These factors were blood urea nitrogen (BUN) > 25 mg/dl, left ventricular ejection fraction < 20%, prior non sustained ventricular tachycardia (NSVT), and female gender.
The baseline clinical characteristics of study patients by the presence of VTA RF in CRT-D patients and the total ICD group are presented in eTable C. Mean age of the study patients was 65 ± 10 years, and 10% were female. Patients with ≥ 1 RF for VTA comprised 47% of the CRT-D population, and had similar baseline characteristics as those without RF, with the exception of a higher baseline creatinine, and a higher frequency of diuretic use. Among the group of CRT-D patients with ≥ 1RF, 82% had only 1 RF, while 17 patients (17%) had two RF, and only two patients (1%) had three RF.