De Winter Pattern Caused by a Large Diagonal Branch Culprit Lesion.

A 70-year-old man was referred to the emergency department for an episode of ongoing chest pain during physical activity. Urgent coronary angiogram revealed a 75% stenosis in the left anterior descending coronary artery and a total occlusion of a large diagonal branch. Both stenoses were treated successfully with percutaneous coronary intervention. After reperfusion, the ECG showed a "De Winter" pattern, which was the ECG expression of a culprit lesion located in a large diagonal branch rather than in the left anterior descending.