Enhanced ventricular synchrony and myocardial function with bipolar left bundle area pacing: a comparative study of anodal ring capture versus unipolar pacing.

AIMS

Cardiac pacing aims to replicate physiological heart rhythm. While left bundle area pacing (LBAP) enhances left ventricular (LV) activation, it often struggles to fully address interventricular dyssynchrony. Bipolar LBAP with anodal ring capture (LBAP-ARC) offers a potential solution by synchronously activating both left and right bundle branches. This study aims to compare the effects of unipolar LBAP and LBAP-ARC on ventricular synchrony and myocardial function.

METHODS AND RESULTS

A prospective cohort study was conducted with enroling 32 patients undergoing successful LBAP implantation. Pacing thresholds, lead impedance, QRS duration, and echocardiographic parameters-including LV and right ventricular (RV) global longitudinal strain (GLS), systolic dyssynchrony index, and interventricular mechanical delay (IVMD)-were assessed under unipolar LBAP and LBAP-ARC configurations. Left bundle area pacing with anodal ring capture significantly improved LV GLS (-16.09% vs. -14.85%, = 0.0006) and reduced IVMD (5.13 ms vs. 21.76 ms, < 0.0001) compared to unipolar LBAP at 1-week follow-up, and these improvements persisted at 3 months (-16.70% vs. -14.98%, = 0.0005 for LV GLS; 8.01 ms vs. 21.75 ms, = 0.0045 for IVMD). Subgroup analysis showed enhanced LV (-16.47% vs. -14.76%, = 0.0094) and RV GLS (-16.24% vs. -15.86%, = 0.0344) in patients with biphasic QRS patterns in leads II/III. Improvements in RV GLS were less pronounced in patients with predominantly positive QRS patterns in leads II/III.

CONCLUSION

Left bundle area pacing with anodal ring capture enhances ventricular synchrony and improves subclinical myocardial function compared to unipolar LBAP, establishing itself as a promising approach in physiological cardiac pacing.