Trileaflet mitral valve in hypertrophic obstructive cardiomyopathy: A rare anatomical variant requiring surgical intervention.

A 68-year-old woman presented with palpitations, though ECG monitoring showed sinus rhythm. Multimodal imaging (cardiac magnetic resonance and echocardiography) showed asymmetric septal hypertrophy with left ventricular outflow tract obstruction (resting gradient of up to 87 mmHg). Echocardiography showed severe mitral regurgitation with multiple regurgitant jets and systolic anterior motion of the mitral valve. Mitral valve anatomy was abnormal, with anterior leaflet restriction and a clefted posterior leaflet. Symptoms persisted despite medical therapy (beta-blockers), and following multidisciplinary discussion, she proceeded to surgery on symptomatic and prognostic grounds. The patient underwent successful septal myectomy and bioprosthetic mitral valve replacement with excellent valve function. Following a generally uneventful postoperative recovery, she was discharged on postoperative day ten with stable cardiac function. This case highlights a rare trileaflet configuration of the mitral valve contributing to severe mitral regurgitation in hypertrophic obstructive cardiomyopathy and underscores the importance of detailed anatomical assessment in guiding surgical decision-making.