Acute Myocardial Infarction in a Young Woman: Role of Cardiac Magnetic Resonance Imaging in Establishing the Diagnosis.

Evaluation of acute coronary syndromes (ACS) in young women presents a clinical challenge. An unremarkable coronary angiogram may not exclude ACS, as spontaneous lesion revascularization, resolved coronary spams, or spontaneous coronary dissection (SCAD) can often be missed. Cardiac magnetic resonance imaging (CMR) can provide useful information in acute myocardial infarction (MI) by confirming and sizing acute infarction and delineating the etiology when angiography is inconclusive. Here, we report a case of a 39-year-old postpartum woman with a history of hyperlipidemia who presented with a one-day history of atypical angina. On presentation, she was found to have transient ST-segment elevation in high lateral leads and elevated troponin. Coronary angiography revealed a nonobstructive lesion in the first obtuse marginal branch (OM1) distribution. The patient subsequently underwent cardiac magnetic resonance imaging (MRI) for further delineation of etiology, which confirmed acute infarction in the OM1 distribution. Diagnosis of myocardial infarction with no obstructive coronary artery disease (MINOCA) secondary to acute coronary artery dissection type 2 (SCAD-2) was made. The patient was managed conservatively with medical therapy. CMR has emerged as a front-line diagnostic imaging modality in acute MI and can provide invaluable information in the confirmation and sizing of infarction, delineating tissue characteristics, establishing the etiology of infarction, and prognostication.