Unadjusted Kaplan-Meier survival curves, stratified by baseline programming. Hazard ratios adjusted for age, gender, DFT at implant, number of treatment zones, brady programming of DDD, LRL, VF detection rate, AF burden, LV pacing, and shock therapy. AV atrioventricular timing, VV ventricular-to-ventricular timing, DFT defibrillation threshold, LRL lower rate limit, VF ventricular fibrillation, AF atrial fibrillation, LV left ventricular