A lateral lead variant of the de Winter pattern due to left main stenosis and left anterior descending artery occlusion.

Early recognition of ST-segment elevation myocardial infarction equivalent electrocardiogram patterns is of paramount importance. Successful identification of these ischemic patterns helps ensure proper triage of patients needing urgent restoration of coronary perfusion. The so-called de Winter sign has become increasingly recognized as a ST-segment elevation myocardial infarction equivalent pattern due to proximal left anterior descending artery occlusion. Yet, despite the de Winter pattern's well-defined electrocardiographic-angiographic relationship, the electrophysiologic explanation for its characteristic electrocardiographic manifestations remains unclear. Herein, we report a case in which an ischemic lateral lead variant of the de Winter pattern emerged from a patient inflicted by an abrupt thrombotic occlusion of the ostial left anterior descending artery, which developed in series with a high-grade stenosis of the distal left main coronary artery. We examine the patient's presenting electrocardiographic findings and clinical course to (i) establish causal inferences that align with the distribution of myocardial ischemia supported by coronary angiography and (ii) provide an accompanying analysis of the relevant scientific literature.