BACKGROUND: Subarachnoid hemorrhage (SAH) is a neurological emergency accounting for 5% of all strokes, with mortality exceeding 50% in patients over 80 years of age. Aneurysmal SAH is particularly lethal in the elderly due to atypical presentations, including ECG abnormalities mimicking acute coronary syndromes, leading to delayed diagnosis and high complication rates. This case report highlights the diagnostic pitfalls of SAH-induced STEMI mimicry.

CASE REPORT: A in their 90s White woman with a remote history of diabetes presented to the Emergency Department (ED) with sudden-onset occipital headache, nausea, and hypertensive crisis (214/68 mmHg). Initial electrocardiography (ECG) showed ST-segment elevations (STEMI) in leads I/aVL with reciprocal depressions in III/aVF, prompting STEMI activation despite normal troponin levels. Emergency computed tomography angiography (CTA) revealed a ruptured 3×1 mm anterior communicating artery (ACOM) aneurysm with Fisher Grade 3 SAH. Echocardiography at admission showed normal ejection and no wall motion abnormalities. ECG performed 1 day after admission showed complete resolution of the ST-T segment changes and the patient did not require any coronary intervention. Despite successful endovascular coiling, her hospital course was complicated by Cronobacter sakazakii bacteremia, embolic infarcts, and refractory cachexia. Palliative care was initiated on hospital day 14 due to irreversible functional decline, culminating in hospice transition.

CONCLUSIONS: SAH-mediated autonomic dysregulation can produce STEMI-like ECG changes even in the absence of coronary ischemia. Geriatric SAH management requires balancing intervention risks against frailty and comorbidities. Early recognition of SAH-induced ECG changes from autonomic-mediated repolarization abnormalities is essential to avoid misdiagnosis and guide appropriate intervention, particularly in older patients in whom comorbidities and frailty complicate recovery trajectories.

Keywords: Aneurysm, Case Reports, Electrocardiography, Subarachnoid Hemorrhage