What is a biphasic T wave?

As a medical professional with expertise in cardiology, I can explain that a biphasic T wave is a specific type of T wave alteration seen on an electrocardiogram (ECG). The T wave represents the repolarization phase of the ventricular muscle after it has been depolarized during a heartbeat. A biphasic T wave appears as an initial positive deflection followed by a negative deflection, or vice versa, and it can be a normal variant in certain leads of a standard 12-lead ECG. However, in the context of Wellens' syndrome, the term refers to a particular ECG pattern characterized by deeply inverted or biphasic T waves in leads V2 and V3. This pattern is highly suggestive of a critical stenosis, or narrowing, of the left anterior descending artery (LAD), which is a serious condition that can lead to a heart attack if not treated promptly. It's important to note that while this ECG pattern is highly specific for LAD stenosis, it is not pathognomonic, meaning it does not confirm the diagnosis by itself. Additional diagnostic tests and clinical evaluation are necessary to confirm the presence of LAD stenosis and to determine the appropriate course of treatment.

Clinical Significance. Wellens' syndrome is a pattern of deeply inverted or biphasic T waves in V2-3, which is highly specific for a critical stenosis of the left anterior descending artery (LAD).