Paradoxical coronary embolism through an atrial septal defect presenting as acute myocardial infarction: A case report

Paradoxical embolism through an atrial septal defect (ASD) is a rare but important cause of acute coronary syndrome (ACS) in patients without conventional cardiovascular risk factors. We report the case of a 40-year-old male with no history of hypertension, diabetes, smoking, dyslipidemia, or family history of premature coronary artery disease who presented with acute chest pain and ischemic electrocardiographic changes. Basic thrombophilia profile screening was nonaffirmative. Troponin-T testing using a point-of-care and quantitative assay was positive. Coronary angiography revealed angiographically normal epicardial coronary arteries. Transthoracic and transoesophageal echocardiography demonstrated a large ostium secundum ASD measuring 22 mm × 24 mm, with a prominent Eustachian valve and significant right-to-left shunting on contrast study, accentuated during the Valsalva maneuver. The patient underwent successful transcatheter ASD closure with complete abolition of shunting. This case highlights paradoxical coronary embolism as a potential mechanism of ACS in young, low-risk individuals and underscores the importance of evaluating intracardiac shunts in patients presenting with ACS and nonobstructive coronaries.