LEFT BUNDLE BRANCH AREA PACING IN A POST TRANSPLANT HEART WITH MILD LV DYSFUNCTION- A CASE REPORT

Left bundle branch pacing (LBBP) is increasingly used as a physiological alternative to right ventricular pacing, with stable thresholds and synchronized left ventricular activation. Its use in a transplanted heart is rarely described, and data on conduction system pacing in this setting is limited. We describe a 38-year-old woman who developed complete atrioventricular dissociation with a wide, LBBB-morphology escape rhythm immediately after orthotopic cardiac transplantation performed for peripartum cardiomyopathy with biventricular dysfunction. Baseline echocardiography showed global LV hypokinesia with an ejection fraction of 45%. Given high-grade AV block with LV dysfunction, we implanted a left bundle branch optimized dual-chamber pacemaker. The paced QRS showed a right bundle branch delay pattern with left axis deviation, in keeping with left posterior fascicular capture, and thresholds remained low and stable at follow-up. The patient has done well since, with a ventricular pacing burden of 100%, no device-related complications, and recovery of LV ejection fraction from 45% to 60% on serial echocardiography. As far as we are aware, this is the first reported instance of left bundle branch pacing in a post-transplant heart. The case suggests that LBBP is feasible in the transplanted heart and may support recovery of LV function even when the heart is denervated, though longer follow-up and further cases will be needed to confirm this. Written informed consent was obtained from the patient for publication of this report and the accompanying images.