Paradoxical Coronary Embolism Presenting as Myocardial Infarction With Non-Obstructive Coronary Arteries: Multimodality Imaging Guiding Structural Intervention

Background Myocardial infarction with non-obstructive coronary arteries (MINOCA) accounts for approximately 6% of acute myocardial infarctions and represents a working diagnosis requiring systematic evaluation to determine the underlying mechanism. Coronary embolism is an under-recognised cause with important therapeutic implications. Case Presentation A 36-year-old man presented with acute chest pain and dynamic troponin elevation (peak 15,019 ng/L). Electrocardiography showed sinus rhythm without ischaemic changes. Coronary angiography demonstrated smooth epicardial vessels with a small distal thrombus in the right posterolateral ventricular branch and no underlying stenosis. Cardiac magnetic resonance imaging confirmed acute subendocardial-to-transmural infarction in the corresponding territory with myocardial oedema, establishing an ischaemic mechanism. Comprehensive thrombophilia and autoimmune screening were negative. Prolonged rhythm monitoring excluded atrial fibrillation. No ventricular thrombus or pulmonary embolism was identified. Transoesophageal echocardiography with agitated saline contrast demonstrated a right-to-left interatrial shunt consistent with patent foramen ovale (PFO). In the absence of alternative embolic sources, paradoxical coronary embolism was diagnosed. The patient was treated with anticoagulation and subsequently underwent successful percutaneous PFO closure. At 1-year follow-up he remained asymptomatic without recurrent embolic events. Discussion This case highlights the importance of structured multimodality evaluation in MINOCA. Concordance between distal angiographic thrombus and territorial late gadolinium enhancement established a clear embolic infarction while excluding myocarditis ( Figure ). Mechanistic clarification directly altered long-term management, supporting structural intervention in a young patient with confirmed paradoxical coronary embolism.