急性冠症候群における診断的難問：左室心膜絞扼

Partial congenital pericardial defects are exceptionally uncommon and typically asymptomatic. In rare circumstances, cardiac herniation through the defect may precipitate mechanical strangulation with extrinsic coronary artery compression and myocardial infarction (MI). We describe a young man who presented with ST-elevation MI attributed to left ventricular (LV) herniation through a previously unrecognized pericardial defect. Despite a typical clinical presentation of MI, the highly atypical angiographic and echocardiographic findings required further investigation. Cardiac magnetic resonance was crucial for excluding alternative causes of LV wall thickening and coronary artery compression, such as tumors or infiltrative diseases, and contributed to identifying the pericardial defect. Although rare, partial pericardial defects should be considered in the differential diagnosis of acute coronary syndrome, especially in young patients with atypical presentations or findings.