Biventricular strain dyssynchrony analysis of left bundle branch area pacing: a prospective, observational study

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Left bundle branch pacing (LBBAP) seems to carry advantages compared to His bundle pacing, such as superior electrical performances and less steep learning curve. Aim of this study was to evaluate technical feasibility, safety, electrical parameters and ventricular synchrony with LBBAP. METHODS: We prospectively enrolled patients receiving LBBAP, such as those with preserved (>50%) left ventricular ejection fraction (LVEF) and narrow QRS, with preserved LVEF and wide QRS, and with LVEF <50%. Electrocardiogram and electrical parameters were evaluated at implant, 24 hours and 3 months. Echocardiographic evaluation was carried out at baseline and after 3 months. Ventricular synchrony was analyzed by time-to-peak-standard-deviation (TPSD) of strain curves of both ventricles. RESULTS: We enrolled a total of 58 patients, in whom, according to currently validated criteria, LBBAP was successful in 56 (97%) patients. In the overall population mean baseline QRS duration was 124.1±30.7 msec, while paced QRS duration was 107.7±13.6 msec (p < 0.001). LVEF improved from 52.9±10.5% to 56.9±8.4%, (p=0.004). Improvement was also observed for interventricular synchrony, by reduction of TPSD difference between LV and RV from 27.9 (10.2–41.5) to 13.9 (4.3-28.7) (p=0.001), and for LV synchrony, by decrease of TPSD delta between LV segments from 38.2 (13.6–53.9) to 15.1 (8.3–31.5) (p <0.001). Ameliorations were consistent in all patient subgroups, irrespective of QRS duration or LVEF. CONCLUSION: LBBAP improves LVEF and both intraventricular (LV) and interventricular (LV-RV) synchronization, irrespective of pacing indication, baseline QRS duration and LV function.