Paradoxical Embolism in Young Patients With Acute Coronary Syndrome Without Coronary Atherosclerosis.

Acute coronary syndrome (ACS) in young patients (<50 years) accounts for 2%-10% of all ACS presentations. We describe a case series of young patients who presented with ACS in the absence of coronary atherosclerosis or other identifiable causes such as spontaneous coronary artery dissection and Takotsubo syndrome. Further diagnostic evaluation, often initiated after cryptogenic stroke or a recurrent systemic embolic event, revealed the presence of significant right-to-left shunting because of an atrial septal defect or patent foramen ovale. After exclusion of other etiologies for thromboembolic events (ie, atrial fibrillation, endocarditis, thrombophilia, and antiphospholipid syndrome), patients underwent successful percutaneous septal closure. These cases underscore the importance of considering paradoxical embolism in the differential diagnosis of ACS in young patients without other etiologies. Percutaneous septal closure may be considered for secondary prevention when paradoxical embolism is suspected.