Double-chambered left ventricle with advanced biventricular failure: a case report

Double-chambered left ventricle (DCLV) is an extremely rare congenital anomaly characterized by an aberrant muscular or fibromuscular septum dividing the left ventricular cavity. Most cases present in childhood or adolescence. Adult presentations are exceptional, particularly when complicated by severe valvular dysfunction and advanced heart failure.

A 50-year-old male with longstanding atrial fibrillation presented with one month of exertional chest tightness and progressive dyspnea, including paroxysmal nocturnal dyspnea. Physical examination revealed a displaced apex and a grade 5/6 holosystolic murmur consistent with severe mitral regurgitation. Electrocardiography showed permanent atrial fibrillation with an extremely high premature ventricular complex burden (52.9%). Transthoracic echocardiography was diagnostic, demonstrating a hypertrophied muscular septum dividing the mid-to-distal left ventricle into a basal and an apical chamber (peak gradient 7 mmHg), severe mitral regurgitation due to restrictive leaflet closure, left ventricular non-compaction, and severe biventricular systolic dysfunction (left ventricular ejection fraction 29.4%). Despite optimization of guideline-directed medical therapy for heart failure with reduced ejection fraction, the patient's symptoms and functional capacity showed no improvement over one month of follow-up. Given the surgically complex anatomy, diffuse myocardial disease, and refractory biventricular failure, the multidisciplinary heart team recommended referral for orthotopic heart transplantation evaluation.

This case highlights that double-chambered left ventricle (DCLV), though typically a pediatric diagnosis, can rarely present in adulthood with severe mitral regurgitation and refractory heart failure, adding to the limited reports of this presentation. In such cases where structural repair is not feasible due to complex anatomy and low intraventricular gradient, heart transplantation evaluation may represent the most appropriate therapeutic strategy, although the long-term response to medical therapy remains to be determined.