What does an abnormal T wave on an ECG mean?

An abnormal T wave on an ECG can indicate a variety of cardiac and non-cardiac conditions. It's important to note that the T wave is the part of the ECG that represents the repolarization, or the recovery phase, of the ventricles after they have contracted to pump blood. Normally, the T wave is in the same direction as the QRS complex, which represents the ventricular depolarization. However, there are exceptions, such as in the right precordial leads where the T wave may be inverted. Abnormal T waves can be due to: 1. Electrolyte imbalances: Conditions like hypokalemia (low potassium) or hyperkalemia (high potassium) can affect the T wave. 2. Myocardial ischemia: Insufficient blood flow to the heart muscle can cause T wave changes. 3. Myocardial infarction: A heart attack can lead to characteristic T wave inversions. 4. Strenuous exercise: Physical exertion can temporarily alter T wave morphology. 5. Drugs or toxins: Certain medications or substances can affect the heart's electrical activity. 6. Non-cardiac conditions: Sometimes, T wave changes are seen in the absence of heart disease, such as in cases of anxiety or other non-cardiac causes. It's crucial to interpret T wave abnormalities in the context of the patient's clinical presentation and other ECG findings. A single abnormal T wave does not necessarily indicate a serious condition and may require further evaluation.

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).