From Isolated Dyspnea to Catastrophic Mechanical Complication: Posteromedial Papillary Muscle Rupture Following Subtle Inferior STEMI

Background: Papillary muscle rupture (PMR) is a rare but rapidly fatal mechanical complication of acute myocardial infarction (MI) that may occur even after apparently limited ischemia. In the contemporary reperfusion era, its incidence is estimated between 0.05% and 0.26% of MIs, yet mortality remains extremely high. Case Summary: A 67-year-old woman with diabetes presented with isolated acute dyspnea and subtle ST-segment elevation in inferior and posterior leads. Transthoracic echocardiography (TTE) revealed inferior wall akinesia and acute severe mitral regurgitation (MR) caused by flail mitral leaflet motion secondary to subtotal rupture of the posteromedial papillary muscle (PMPM). Within hours of admission, she developed sudden neurological deficits consistent with hyperacute ischemic stroke, followed by massive pulmonary edema and refractory cardiogenic shock (CS). Despite intensive supportive management and planned urgent surgical intervention, the patient died before surgery could be performed. Discussion: PMR remains one of the most devastating mechanical complications of MI, with mortality reaching up to 80% without surgical treatment. This case highlights the importance of recognizing atypical presentations of myocardial infarction, particularly in diabetic patients presenting without chest pain. The case is valuable for the scientific and clinical community as it emphasizes the need for early echocardiographic evaluation and rapid multidisciplinary management. Furthermore, the combination of PMR and acute ischemic stroke represents an uncommon and educational clinical scenario.