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 (CRTbl), native, and different CRT configurations.

RESULTS

SDAT 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.

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.