Silent but Deadly: A Case of Obtuse Marginal Artery Occlusion

The obtuse marginal artery (OMA) is a key branch of the left circumflex coronary artery, supplying blood to the lateral wall of the left ventricle. OMA occlusions can result in myocardial ischemia and serious cardiac events, often presenting with subtle or atypical electrocardiogram (EKG) changes, unlike the more pronounced alterations observed with left anterior descending artery occlusions. This case report discusses a 57-year-old female presenting with chest pain and shortness of breath, indicative of acute coronary syndrome. The patient's initial EKG showed occasional premature ventricular contractions (PVCs), T-wave flattening in aVL, and 1 mm ST elevation in V6, but otherwise, it was normal appearing. Despite not having typical EKG abnormalities, the patient suffered a cardiac arrest. Coronary angiography confirmed 100% stenosis of the first OMA branch, which was successfully treated with aspiration thrombectomy and stent placement. The patient did not have collateral coronary vessels, and therefore, did not have a role in making the patient's EKGs difficult to interpret. This case emphasizes the challenges posed by OMA occlusions, underscoring the necessity for a high index of suspicion during the early stages of a patient's presentation for prompt diagnosis and treatment.