Mitral Annular Subvalvular Aneurysm With Leaflet Perforation and Left Atrium-to-Left Ventricle Fistulous Communication.

BACKGROUND

Mitral annular subvalvular aneurysm (MASA) is a rare cardiac condition with variable etiology and potentially life-threatening complications.

CASE SUMMARY: A 35-year-old previously healthy man of African descent presented with progressive dyspnea and weight loss. Multimodality imaging revealed a posterior MASA complicated by leaflet perforation, left atrium-to-left ventricle fistula, and severe mitral regurgitation. Despite negative microbiological and histological results, morphological and intraoperative findings strongly suggested healed infective endocarditis rather than a congenital origin. Urgent mitral valve replacement with aneurysm exclusion was successfully performed.

DISCUSSION: This case highlights the diagnostic and surgical value of multimodality imaging-including echocardiography, cardiac computed tomography, and magnetic resonance-in confirming MASA and supporting an acquired inflammatory etiology when infectious work-up is inconclusive.

TAKE-HOME MESSAGES: MASA secondary to healed endocarditis should be suspected in the presence of leaflet perforation, atrioventricular fistula, and severe mitral regurgitation. Comprehensive multimodality imaging is essential for diagnosis and surgical planning.