As a domain expert in cardiology, I can explain that the T wave is a crucial part of the electrocardiogram (ECG), which is a test that measures the electrical activity of the heart. The T wave represents the repolarization phase of the cardiac cycle, which is the recovery period for the heart's ventricular muscle cells after they have contracted. In a typical ECG, the T wave follows the QRS complex, which corresponds to the ventricular depolarization. The T wave is said to be the most labile wave in the ECG, meaning it is the most sensitive to changes and can be affected by a variety of factors, both cardiac and non-cardiac. Changes in the T wave, such as low-amplitude or abnormally inverted T waves, can be indicative of many different conditions affecting the heart. Normally, the direction of the T wave is the same as that of the QRS complex, with the exception of the right precordial leads (specifically lead V2), where the T wave may be in the opposite direction. These variations can provide valuable diagnostic information to healthcare professionals. read more >>

The T wave is the most labile wave in the ECG. T wave changes including low-amplitude T waves and abnormally inverted T waves may be the result of many cardiac and non-cardiac conditions. The normal T wave is usually in the same direction as the QRS except in the right precordial leads (see V2 below).read more >>