Clinical outcomes with synchronized left ventricular pacing: analysis of the adaptive CRT trial

Acute studies have suggested that left ventricular pacing (LVP) may have benefits over biventricular pacing (BVP). The adaptive cardiac resynchronization therapy (aCRT) algorithm provides LVP synchronized to produce fusion with the intrinsic activation when the intrinsic atrioventricular (AV) interval is normal. The randomized double-blind adaptive cardiac resynchronization therapy trial demonstrated noninferiority of the aCRT algorithm compared to echocardiography-optimized BVP (control). Objective To examine whether synchronized LVP (sLVP) resulted in better clinical outcomes. Methods First, stratification by percent sLVP ( sLVP) and multivariate Cox proportional hazards model was used to assess the relationship between sLVP and clinical outcomes. Second, outcomes were compared between patients in the aCRT arm (n = 318) and control patients (n = 160) stratified by intrinsic AV interval at randomization. Results In the aCRT arm, sLVP =50 (n = 142) was independently associated with a decreased risk of death or heart failure hospitalization (hazard ratio 0.49; 95 confidence interval 0.28-0.85; P =.012) compared with sLVP