Impact on mitral regurgitation in patients with AVB undergoing permanent pacemaker implantation: left bundle branch pacing vs. right ventricular septum pacing

TL;DR

This study compares two pacemaker techniques in AVB patients and finds that left bundle branch pacing reduces mitral regurgitation and improves heart function more effectively than right ventricular pacing.

Contribution

The study demonstrates that left bundle branch pacing (LBBP) is superior to right ventricular septum pacing (RVSP) in reducing mitral regurgitation and improving left ventricular remodeling in AVB patients.

Findings

LBBP was associated with significant reductions in mitral regurgitation severity compared to RVSP.

LBBP led to improved left ventricular remodeling and systolic function in AVB patients.

Baseline left ventricular end-diastolic diameter was independently linked to MR severity reduction in LBBP patients.

Abstract

Patients with atrioventricular block (AVB) who require pacemaker implantation frequently present with varying degrees of mitral regurgitation (MR), which may influence left ventricular (LV) remodeling and function. This study aimed to evaluate the impact of left bundle branch pacing (LBBP) versus right ventricular septum pacing (RVSP) on MR severity and LV performance.

A total of 137 consecutive AVB patients undergoing pacemaker implantation via LBBP or RVSP were retrospectively enrolled, after excluding those with previous mitral valve surgery or structural valvular abnormalities. Baseline and follow-up echocardiography evaluations were used to assess changes in MR severity and LV function. Subgroup analyses were performed among patients with baseline MR.

Out of the total cohort, 88 patients (64.2%) successfully underwent LBBP, while the remaining 49 patients (35.8%) received RVSP when LBBP could not be achieved. The average age and sex distribution were similar between the two groups. Significant changes in MR area and severity at follow-up were observed in patients with LBBP compared to those with RVSP (P < 0.05). LBBP was independently associated with a higher likelihood of MR improvement among patients who received pacemaker implants [hazard rate (HR) = 0.238, CI = 0.105–0.538; P < 0.001]. At follow-up, those in the LBBP subgroup with moderate or severe MR demonstrated significantly shorter lead–TVA distance, increased left atrium diameters, poor LV ejection fraction (LVEF), and higher mitral E/A ratios (P < 0.05) compared with those in the none or mild MR subgroup. Among LBBP patients who showed a reduction in MR severity, there was a significant improvement in LV remodeling (ΔLVEDD) from the baseline (P = 0.009). Furthermore, these patients demonstrated a non-significant trend toward better LV function, reflected by greater changes in LVEF and E/A ratio (ΔLVEF and ΔE/A).

LBBP significantly reduced MR severity and improved LV remodeling and systolic function compared with RVSP. Moreover, LBBP and baseline LVEDD were independently associated with a reduction in MR severity among AVB patients undergoing pacemaker implantation, highlighting the superiority of LBBP as a preferred pacing strategy in this population.

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