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 (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). METHODS: 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. RESULTS: 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 (R(2) = 0.665, P < 0.01) and the pacing opt-AV (opt-PAV) = 0.25 × PAV(opt-AV) + 0.5 × PAV(opt-V) + 30 ms (R(2) = 0.560, P < 0.01). CONCLUSION: 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.