What is the T wave in an ECG?

As a medical professional with expertise in cardiology, I can explain the significance of the T wave in an electrocardiogram (ECG). An ECG is a diagnostic tool that measures and records the electrical activity of the heart. The T wave is a crucial part of the ECG waveform, representing the repolarization phase of the ventricular muscle fibers. This phase occurs after the ventricular depolarization, which is represented by the QRS complex on the ECG. The T wave is typically positive (upright) in leads that face the end of the ventricular depolarization. It follows the S wave (the downward deflection after the R wave in the QRS complex) and precedes the isoelectric segment, which is the period of electrical silence before the next P wave initiates the next heartbeat. Abnormalities in the T wave, such as inversion, flattening, or increased amplitude, can indicate various cardiac conditions. For instance, T wave inversion can be a sign of ischemia, infarction, or other heart diseases. Prominent T waves may suggest hyperkalemia (high potassium levels in the blood), while flattened T waves can be associated with conditions like hypothyroidism. It's important to interpret the T wave in the context of the entire ECG and the patient's clinical presentation to determine its clinical significance.

In electrocardiography, the T wave represents the repolarization, or recovery, of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. ... However, a negative T wave is normal in lead aVR.