Wellens' syndrome (WS) is a pattern on an electrocardiogram (ECG) characterized by biphasic T waves or deeply inverted T waves in leads V2-V3 with a recent clinical history of angina. Wellens' pattern on the ECG is particular for critical left anterior descending artery (LAD) stenosis. Wellens' sign and WS have been used interchangeably in the literature. However, the typical patterns of ECG changes noted are mostly represented by Wellens' sign. These ECG changes have been crucial in identifying this subset of patients with severe LAD disease.