Abstract
BACKGROUND: It is unclear whether clinical benefits of cardiac resynchronization can be achieved by pacing only the left ventricle. HYPOTHESIS: We aimed to compare the effect of a novel adaptive left ventricular-only fusion pacing (LVP) on ventricular function with conventional biventricular pacing (BVP) in cardiac resynchronization therapy (CRT) indicated patients. METHODS: This prospective, randomized, multicenter study enrolled CRT-indicated patients with PR interval ≤ 200 ms who were randomized in the adaptive LVP group (using the AdaptivCRT™ algorithm with intentional non-capture right ventricular pacing) or the echocardiography-optimized BVP group. Cardiac function and echocardiography were evaluated at baseline and follow-ups. CRT super response was defined as two-fold or more increase of left ventricular ejection fraction (LVEF) or final LVEF >45%, and LV end-systolic volume (LVESV) decrease >15%, and New York Heart Association (NYHA) class improved by at least one level. RESULTS: Sixty-three patients were enrolled in the study (LVP = 34 vs. BVP = 29). At 6-month follow-up, significant improvements in LVEF, LVESV, and NYHA class were observed in both groups. The CRT super response rate was significantly higher in patients with high-percentage adaptive LV-only pacing in LVP group (68.4%) than in BVP group (36.4%, p = .04). CONCLUSIONS: Adaptive LV-only pacing was comparable to BVP in improving cardiac function and clinical condition in CRT-indicated patients. This finding raises the possibility that an adaptive LVP algorithm with appropriate right ventricular sensing to fuse with intrinsic right ventricular activation in a two-lead (right atrium and left ventricle) device may provide clinical benefit in a subset of CRT patients with intact atrioventricular conduction.