South African Flag Sign on Electrocardiogram

The South African Flag Sign (SAFS) is a rare electrocardiographic pattern associated with occlusion myocardial infarction, typically involving the first diagonal branch. A 74-year-old woman presented with acute chest pain and a transient neurological deficit following intense emotional stress. The admission electrocardiogram demonstrated the SAFS. Emergency coronary angiography revealed nonobstructive coronary artery disease, whereas echocardiography and cardiac magnetic resonance confirmed Takotsubo syndrome with apical ballooning and an initial left ventricular ejection fraction of 36%. Clinical and functional recovery was achieved with guideline-directed medical therapy. High-risk ST-segment elevation equivalents like the SAFS, though excluded from standard ST-segment elevation myocardial infarction criteria, indicate occlusion myocardial infarction requiring emergent reperfusion. This case illustrates how severe catecholaminergic discharge in Takotsubo syndrome can induce microvascular dysfunction and vasospasm, faithfully mimicking epicardial occlusions and acute cerebrovascular events. High-risk electrocardiogram patterns such as the SAFS are not exclusive to occlusion myocardial infarction and may indicate other mechanisms of acute myocardial injury.