Real-time assessment of inter and intraventricular synchrony in cardiac resynchronization therapy with left bundle branch pacing using ECGi and low-frequency QRS analysis.

INTRODUCTION

Left bundle branch pacing (LBBP) is an alternative to conventional biventricular pacing for cardiac resynchronization therapy (CRT).

METHODS

A 76-year-old male was referred for CRT via left bundle branch pacing (LBBP). We present the real-time characterization of the transition from intrinsic left bundle branch block (LBBB) to sequential pacing modalities: right ventricular septal pacing (RVSP), left ventricular septal pacing (LVSP), and finally LBBP. Epicardial activation maps from electrocardiographic imaging (ECGi) and low-frequency (LF) QRS analysis were used to provide complementary insights into inter- and intraventricular synchrony.

RESULTS

LVSP, LBBP, and anodal capture improved activation compared with baseline, with LBBP achieving the greatest improvements in interventricular and LV intraventricular synchrony despite higher RV dispersion.

CONCLUSION

These findings highlight ECGi and LF QRS as valuable tools to guide CRT.