Cardioembolic ST-Elevation Myocardial Infarction in a Patient With Atrial Fibrillation and Polycythemia Vera.

ST-elevation myocardial infarction (STEMI) is most commonly caused by acute atherosclerotic plaque rupture with superimposed thrombosis. Coronary embolism represents a rare but clinically important non-atherosclerotic mechanism of STEMI, which is frequently associated with atrial fibrillation and other prothrombotic conditions. Embolic STEMI has been associated with higher rates of adverse outcomes and requires a management strategy distinct from atherosclerotic disease. We present a 61-year-old male with paroxysmal atrial fibrillation and polycythemia vera who presented with anterolateral STEMI. Coronary angiography revealed occlusion of the distal left anterior descending and diagonal branches without underlying atherosclerosis, consistent with a cardioembolic etiology. He was managed with anticoagulation without stenting and discharged on long-term oral anticoagulation. This case highlights the importance of considering coronary embolism in patients with arrhythmias or hypercoagulable states presenting with STEMI. Early recognition allows avoidance of unnecessary coronary stenting, guides appropriate anticoagulation, and supports targeted strategies to prevent recurrent thromboembolic events.