Left bundle branch pacing in double-chambered left ventricle and perimembranous ventricular septal aneurysm: a case report

Abstract Background Double-chambered left ventricle and perimembranous ventricular septal aneurysm are rare congenital heart abnormalities that often remain undetected until adulthood. Both abnormalities can be associated with conduction disorders requiring cardiac pacing. To our knowledge, this is the first case report of a patient with both a double-chambered left ventricle and a perimembranous ventricular septal aneurysm, undergoing left bundle branch area pacing (LBBAP) due to complete atrioventricular (AV) block. Case summary A 31-year-old man with complete AV block was admitted to our centre, where diagnostic evaluation revealed a complex congenital heart defect: a large perimembranous septal aneurysm and a double-chambered left ventricle. Due to high predicted pacing burden, conduction system pacing with LBBAP was attempted. In addition to the standard technique, transoesophageal echocardiography (TEE) was used intraoperatively to facilitate safe positioning of the LBBAP lead. Finally, engagement of the conduction system was confirmed and preserved at the 1-year follow-up, with stable pacing parameters. Discussion Conduction system pacing in congenital heart defects can be technically challenging due to complex anatomy. This case highlights LBBAP as a feasible physiological pacing option, even in complex and rare congenital heart defects. To minimise procedural risk, careful preprocedural multimodality imaging and intraoperative utilization of TEE were essential for optimal lead positioning in the setting of abnormal septal structures.