Aplastic Posterior Mitral Leaflet with an Unusual Clinical Course

Abstract A 72-year-old man presenting with progressive dyspnea was evaluated. Transthoracic and consequently transesophageal echocardiography verified severe mitral regurgitation (MR) caused by hypoplasia of the posterior mitral leaflet (PML) and flail of A2 scallop. A review of reported cases reveals that PML hypoplasia is an uncommon diagnosis among the adult population which can be tolerated relatively well and carries a good prognosis. Our patient had a unique course of the disease. Previously presenting with a bicuspid aortic valve and a nonsignificant MR in spite of the severely hypoplastic PML. Eventually, he became symptomatic years later as severe MR developed due to chordal rupture and flail of the anterior mitral leaflet.