A Deadly Mimic: Type A Aortic Dissection Presenting as Inferior STEMI

Abstract

Acute Type A aortic dissection is a life threatening cardiovascular emergency that may present with clinical and electrocardiographic findings resembling acute myocardial infarction, creating a significant diagnostic challenge. We report the case of a 58 year old male with a history of hypertension who presented to the emergency department with sudden onset severe central chest pain radiating to the back, associated with diaphoresis, nausea, and vomiting. On arrival, he was tachycardic and relatively hypotensive but remained alert and neurologically intact. Initial electrocardiography demonstrated hyperacute T waves in the inferior leads with reciprocal ST segment depression in the anterior leads, representing an inferior STEMI equivalent pattern. High sensitivity troponin was elevated, further supporting an initial diagnosis of acute coronary syndrome. Despite treatment and preparation for urgent coronary angiography, persistent chest pain radiating to the interscapular region, mild mediastinal widening on chest radiography, and relative hypotension prompted further evaluation. Bedside transthoracic echocardiography demonstrated a mildly dilated ascending aorta, a small pericardial effusion, and findings suspicious for an intimal flap. Subsequent computed tomography angiography confirmed an extensive Stanford Type A aortic dissection involving the ascending aorta and aortic root with extension to the origin of the right coronary artery, resulting in coronary malperfusion. The patient underwent prompt medical stabilization with intravenous beta blockade and analgesia before transfer to a tertiary cardiothoracic center, where successful emergency surgical repair was performed. His postoperative recovery was uncomplicated, and he was discharged home in stable condition. This case highlights the importance of maintaining a broad differential diagnosis in patients presenting with apparent STEMI, particularly when atypical features such as abrupt pain onset, radiation to the back, hypotension, or mediastinal widening are present. Early recognition of aortic dissection and timely use of bedside imaging can prevent inappropriate antithrombotic therapy and facilitate life saving surgical intervention.