Abstract
Purpose of the study: Previous studies investigated the role of intrinsic conduction for cardiac resynchronization therapy (CRT) optimization. We investigated the role of the fusion between pacing-induced activation and intrinsic conduction in CRT, by evaluating the acute hemodynamic effects of simultaneous His bundle and left ventricular (LV) pacing.
Method used: We studied 11 patients with systolic heart failure and left bundle-branch block scheduled for implantation of a CRT device. At implantation, LV pressure and volume data were determined via conductance catheter. Standard leads were placed in the right atrium, at the apex of the right ventricle (RVA) and in a lateral or posterior-lateral coronary vein. An additional electrode was temporarily positioned in His bundle. Following pacing configurations were systematically assessed: standard biventricular pacing (RVA + LV), LV only pacing (LV-only), His bundle pacing (HIS), simultaneous His bundle and LV pacing (HIS + LV). Each configuration was compared with the AAI mode at multiple atrioventricular intervals.
Summary of results: In comparison with AAI mode, RVA + LV and LV-only pacing resulted in improved stroke volume (85 ± 32ml and 86 ± 33ml versus 58 ± 23ml), stroke work, maximum pressure-derivative and systolic dyssynchrony at individual optimal interval. The optimal atrioventricular delay was close to the P-H interval in the majority of patients. By contrast, HIS-LV pacing improved hemodynamic indexes at all atrioventricular intervals (stroke volume >76ml at all fixed intervals and 88 ± 31ml at optimal interval).
Conflict of interest: none
