Body surface activation mapping of electrical dyssynchrony in cardiac resynchronization therapy patients: Potential for optimization

Background: Electrical synchronization is likely improved by cardiac resynchronization therapy (CRT), but is difficult to quantify with 12-lead ECG. We aimed to quantify changes in electrical synchrony and potential for optimization with CRT using a body-surface activation mapping (BSAM) system. Methods: Standard deviation of activation times (SDAT) was calculated in 94 patients using BSAM at baseline CRT (CRTbi), native, and different CRT configurations. Results: SDAT decreased 20% from native to CRTbi (p < 0.01) and an additional 26% (p < 0.01) at optimal CRT (CRTopt), the minimal SDAT setting. Patients with LBBB and patients with QRS duration 150 ms had higher native SDAT and greater decrease with CRTbi (p < 0.01); however, the improvement from CRTbi to CRTopt was similar in all four groups (range: 24-28%). CRTopt was achieved with biventricular pacing in 52% and LV-only pacing in 44%. We propose that improved wavefront fusion demonstrated by BSAMs contributed substantially to the improved electrical synchrony. Conclusion: Optimization potential is similar regardless of pre-CRT QRS morphology or duration. BSAM could possibly improve CRT response by individualizing device programming to minimize electrical dyssynchrony. (C) 2017 Elsevier Inc. All rights reserved.