An electrographic AV optimization for the maximum integrative atrioventricular and ventricular resynchronization in CRT

Background:Atrioventricular (AV) delay could affect AV and ventricular synchrony in cardiac resynchronization therapy (CRT). Strategies to optimize AV delay according to optimal AV synchrony (AVopt-AV) or ventricular synchrony (AVopt-V) would potentially be in discordant. This study aimed to explore a new AV delay optimization algorithm guided by electrograms to get the maximum integrative effects of AV and ventricular resynchronization (opt-AV).Methods:Forty-nine patients with CRT were enrolled. AVopt-AV was measured through the Ritter method. AVopt-V was obtained by yielding the narrowest QRS. The opt-AV was considered to be AVopt-AV or AVopt-V when their difference was <20ms, and to be the AV delay with the maximal aortic velocity-time integral between AVopt-AV and AVopt-V when their difference was >20ms.Results:The results showed sensing/pacing AVopt-AV (SAVopt-AV/PAVopt-AV) were correlated with atrial activation time (Pend-As/ Pend-Ap)( P＜0.05 ). Sensing/pacing AVopt-V (SAVopt-V/PAVopt-V) were correlated with the intrinsic AV conduction time (As-Vs/Ap-Vs) (P＜0.01). The percentages of patients with more than 20ms differences between SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V were 62.9% and 57.1%, respectively. Among them, the opt-AV were linearly correlated with SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V. The sensing opt-AV (opt-SAV)=0.1×SAVopt-AV+0.4×SAVopt-V+70ms (R2=0.665, P<0.01) and the pacing opt-AV (opt-PAV)=0.25×PAVopt-AV+0.5×PAVopt-V+30ms (R2=0.560, P<0.01).Conclusion:The SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V were correlated with the atrial activation time and the intrinsic AV conduction interval respectively. Almost half of patients had a >20ms difference between SAVopt-AV/PAVopt-AV and SAVopt-V/PAVopt-V. The opt-AV could be estimated based on electrogram parameters.