BACKGROUND: Coronary artery embolism (CAE) is an infrequent but clinically significant non-atherosclerotic cause of ST-elevation myocardial infarction (STEMI). It presents unique diagnostic and therapeutic challenges due to its varied etiologies and the frequent absence of significant coronary artery disease. While atrial fibrillation is the most recognized cardiac arrhythmia associated with coronary embolism, atrial flutter as an embolic source remains underreported. This report highlights the complexities of diagnosing and managing CAE manifesting as an atypical STEMI and sudden cardiac arrest in a patient with previously undiagnosed atrial flutter, emphasizing the critical importance of identifying underlying embolic sources, particularly atrial flutter, to guide appropriate therapy.

CASE REPORT: An 82-year-old woman with non-ischemic cardiomyopathy presented after an out-of-hospital ventricular fibrillation cardiac arrest. Her post-resuscitation electrocardiogram revealed an inferior STEMI. Emergency coronary angiography demonstrated abrupt embolic occlusions in the distal right coronary artery, without evidence of significant underlying atherosclerosis. Percutaneous coronary intervention was performed to restore blood flow. After the procedure, telemetry revealed new-onset atrial flutter, the presumed embolic source. Her hospital course was complicated by severe global hypokinesis out of proportion to the infarct territory and progressive respiratory failure, ultimately leading to a family decision to transition to comfort care.

CONCLUSIONS: This case underscores the critical need to consider coronary artery embolism in the differential diagnosis for STEMI, particularly in patients lacking significant atherosclerotic disease burden. The presence of arrhythmias, such as atrial flutter, should raise strong clinical suspicion for an embolic etiology. While a good outcome was not achieved in this specific case, early recognition of CAE remains crucial for guiding appropriate revascularization strategies and initiating prompt anticoagulation to prevent recurrent thromboembolic events in surviving patients.

Keywords: Atrial Flutter, Cardiology, Case Reports, Coronary Embolism, percutaneous coronary intervention, ST elevation myocardial infarction