Abstract An 81-year-old woman was referred for primary angioplasty due to a myocardial infarction. Upon her arrival, the patient was in cardiogenic shock. Coronarography revealed a large filling defect within the left main coronary artery. Thromboaspiration was performed, obtaining thrombotic material and tissue of different consistencies. Balloon angioplasty in the left anterior descending and left main arteries was performed, resulting in incomplete reperfusion, leading to irreversible electromechanical dissociation. Analysis of the aspirated material was consistent with thrombus, atheroma, and calcified tissue. Autopsy revealed a heavily calcified mitral valve, and distal embolization of amorphous material in the microvasculature identical to that found in the mitral valve subapparatus. < Learning objective: Acute myocardial infarction due to left main embolization of tissue from mitral valve subapparatus is a rare condition but lethal. Early recognition of this condition is important for establishing the best option of treatment, between a percutaneous or surgical approach.>