Case Report: Rupture of multiple perforating branches and fatal giant interventricular septal hematoma: a severe complication of left bundle branch area pacing

Background Left bundle branch area pacing (LBBAP) is generally safe. Giant interventricular septal hematoma (IVSH) is an extremely rare complication of LBBAP. Previously reported cases had favorable outcomes, and no fatal cases have been reported to date. Case summary A 67-year-old male with 4 years of dilated cardiomyopathy (DCM) and refractory heart failure (HF) had a preoperative left ventricular ejection fraction (LVEF) of 13.2% and left bundle branch block. Following HF stabilization, cardiac resynchronization therapy defibrillator (CRTD) implantation was performed. Intraoperative LBBAP correction was unsatisfactory, and left ventricular lead placement failed. The patient developed chest pain and hypotension 5 h postoperatively. Bedside echocardiography detected a giant IVSH causing biventricular compression and pericardial effusion. Despite emergency extracorporeal membrane oxygenation (ECMO) support, pericardial drainage and interventional embolization, his condition worsened rapidly. Coronary angiography (CAG) identified rupture of multiple septal perforator branches. He succumbed to irreversible circulatory collapse 10 h after surgery. Conclusion Although most patients with LBBAP-associated IVSH achieve a favorable prognosis with timely intervention, the condition can progress rapidly and pose a life-threatening risk in those with end-stage severe HF.