Oligosymptomatic Anterolateral Papillary Muscle Rupture Following Myocardial Infarction: A Case Report

Background Papillary muscle rupture is a rare but often life-threatening complication of myocardial infarction, typically associated with severe hemodynamic instability. We report an unusual case of anterolateral papillary muscle rupture presenting minimal symptoms. Case Presentation A 54-year-old man with a history of non-ST elevation myocardial infarction (NSTEMI) nine months earlier—treated with drug-eluting stents in the circumflex and obtuse marginal arteries—was referred for evaluation of severe mitral regurgitation. He remained in NYHA functional class II during follow-up. Transthoracic and transesophageal echocardiography revealed posterior mitral leaflet prolapse due to chordal rupture. Intraoperative findings confirmed a micro-rupture of the anterolateral papillary muscle. An initial attempt at mitral valve repair was made but subsequently converted to valve replacement due to persistent regurgitation. The postoperative course was complicated by pericardial effusion, which was resolved with appropriate management. The patient was discharged on postoperative day 15 without further complications. Conclusions This case highlights a rare presentation of anterolateral papillary muscle rupture with subtle clinical symptoms, emphasizing the importance of comprehensive echocardiographic evaluation, even in hemodynamically stable patients with a history of myocardial infarction.