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

Abstract

BackgroundElectrical 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. MethodsStandard deviation of activation times (SDAT) was calculated in 94 patients using BSAM at baseline CRT (CRTbl), native, and different CRT configurations. ResultsSDAT decreased 20% from native to CRTbl (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 ≥150ms had higher native SDAT and greater decrease with CRTbl (p<0.01); however, the improvement from CRTbl 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. ConclusionOptimization 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.