Reverse electrical remodelling after cardiac resynchronization therapy in a patient undergoing left bundle branch area pacing: a case report

Abstract

Background Left bundle branch area pacing (LBBAP) has been introduced as an alternative to biventricular pacing in cardiac resynchronization therapy (CRT). Several studies describe echocardiographic reverse remodeling after LBBAP. Reverse electrical remodeling after LBBAP has not yet been described. Case summary A 77-year-old female with non-ischemic heart failure with reduced ejection fraction (LVEF 30-35%), left bundle branch block (QRS duration 164ms) and symptomatic atrial fibrillation irresponsive to pharmacological therapy was evaluated for CRT with LBBAP and AV node ablation. Successful LBBAP implantation resulted in confirmed left bundle branch capture. Immediately after implantation paced QRS duration was 194ms with a long stimulus-V6RWPT (time to peak R wave in V6) of 93ms, suggesting distal conduction system disease. Patient showed an echocardiographic improvement (LVEF 35% to 50%) and improvement in symptoms (NYHA III to NYHA II) at one year follow-up. Moreover, an improvement in conduction delays was found present. Paced QRS duration improved to 159ms and stimulus-V6RWPT improved to 78ms. This improvement might be due to reverse electrical remodeling. Discussion This case demonstrates that left bundle branch area pacing can induce reverse electrical remodeling, even in the presence of distal conduction system disease. With the current availability of different pacing strategies in CRT (i.e. biventricular CRT, LBBAP, left bundle branch-optimized CRT) more research on patient selection and pacing strategy selection is needed.