Dynamic atrioventricular delay programming improves ventricular electrical synchronization as evaluated by 3D vectorcardiography

Background: Optimal timing of the atrioventricular delay in cardiac resynchronization therapy (CRT) can improve synchrony in patients suffering from heart failure. The purpose of this study was to evaluate the impact of SyncAV (TM) on electrical synchrony as measured by vectorcardiography (VCG) derived QRS metrics during biventricular (BiV) pacing. Methods: Patients implanted with a cardiac resynchronization therapy (CRT) device and quadripolar left ventricular (LV) lead underwent 12-lead ECG recordings. VCG metrics, including QRS duration (QRSd) and area, were derived from the ECG by a blinded observer during: intrinsic conduction, BiV with nominal atrioventricular delays (BiV Nominal), and BiV with SyncAV programmed to the optimal offset achieving maximal synchronization (BiV + SyncAV Opt). Results: One hundred patients (71% male, 40% ischemic, 65% LBBB, 32 +/- 9% ejection fraction) completed VCG assessment. QRSd during intrinsic conduction (166 +/- 25 ms) was narrowed successively by BiV Nominal (137 +/- 23 ms, p <.05 vs. intrinsic) and BiV + SyncAV Opt (122 +/- 22 ms, p Conclusion: With VCG-based, patient-specific optimization of the programmable offset, SyncAV reduced electrical dyssynchrony beyond conventional CRT. Crown Copyright (C) 2019 Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)