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

Atrioventricular (AV) delay could affect AV and ventricular synchrony in cardiac resynchronization therapy (CRT). Strategies to optimize AV delay according to optimal AV synchrony (AV_opt-AV) or ventricular synchrony (AV_opt-V) would potentially be discordant. This study aimed to explore a new AV delay optimization algorithm guided by electrograms to obtain the maximum integrative effects of AV and ventricular resynchronization (opt-AV).

Forty-nine patients with CRT were enrolled. AV_opt-AV was measured through the Ritter method. AV_opt-V was obtained by yielding the narrowest QRS. The opt-AV was considered to be AV_opt-AV or AV_opt-V when their difference was < 20 ms, and to be the AV delay with the maximal aortic velocity-time integral between AV_opt-AV and AV_opt-V when their difference was > 20 ms.

The results showed that sensing/pacing AV_opt-AV (SAV_opt-AV/PAV_opt-AV) were correlated with atrial activation time (P_end-As/P_end-Ap) (P < 0.05). Sensing/pacing AV_opt-V (SAV_opt-V/PAV_opt-V) was correlated with the intrinsic AV conduction time (As-Vs/Ap-Vs) (P < 0.01). The percentages of patients with more than 20 ms differences between SAV_opt-AV/PAV_opt-AV and SAV_opt-V/PAV_opt-V were 62.9% and 57.1%, respectively. Among them, opt-AV was linearly correlated with SAV_opt-AV/PAV_opt-AV and SAV_opt-V/PAV_opt-V. The sensing opt-AV (opt-SAV) = 0.1 × SAV_opt-AV + 0.4 × SAV_opt-V + 70 ms (R² = 0.665, P < 0.01) and the pacing opt-AV (opt-PAV) = 0.25 × PAV_opt-AV + 0.5 × PAV_opt-V + 30 ms (R² = 0.560, P < 0.01).

The SAV_opt-AV/PAV_opt-AV and SAV_opt-V/PAV_opt-V were correlated with the atrial activation time and the intrinsic AV conduction interval respectively. Almost half of the patients had a > 20 ms difference between SAV_opt-AV/PAV_opt-AV and SAV_opt-V/PAV_opt-V. The opt-AV could be estimated based on electrogram parameters.