What is a T-wave on ECG?
T-wave on the ECG reflects the sum repolarization of the right and the left ventricles. It represents the relaxation phase of the heart. During the T-wave, the ventricles prepare for the next heartbeat [1].
The direction and shape of the T-wave are influenced by the heart muscle, intraventricular pressure, QRS complex duration, and blood flow [1].
Abnormal shape or duration of the repolarization wave can be a sign of heart disease, such as myocardial ischemia [2].
How does a normal T-wave look like on an ECG?
The direction of a normal T-wave depends on the lead. It is upwards/positive in lead V3 to V6 and leads I and II, while in aVR, the direction of the wave is normally downwards/negative. In the rest of the leads, the T-wave presentation can vary [3].
The shape of the T-wave depends on the ventricular action potential duration distribution. Simply, it depends on how the repolarization wave progresses through the heart muscle [4, 5].
Normal morphology of the T-wave is typically characterized by a slower upward slope and a faster decline [6].
The height of a normal T-wave should not exceed 5 mm in the leads I, II, III, aVR, aVL, and aVL. Meanwhile, in the chest leads (V1-V6), the amplitude should not be more than 10 mm [6].
What is a nonspecific T-wave abnormality?
A nonspecific T-wave abnormality is a small change in the T-wave on the ECG that does not match any particular diagnosis. Small changes in the T-wave are common and occur in cardiological as well as non-cardiological conditions [7].
For instance, nonspecific T-wave changes can occur in hypertension. In the clinic, they can help identify ineffective blood pressure control [8].
What can cause a nonspecific T-wave abnormality?
Nonspecific T-wave abnormality can often be found in healthy, asymptomatic people. However, they can be an indicator of a disease [7].
Among the diseases that can cause nonspecific changes in the T-wave is coronary artery disease [9].
Myocardial edema is another condition that can lead to similar changes in the T-wave. It is a condition during which the heart muscle swells, interfering with the heart's function [10].
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Should I see a cardiologist with a nonspecific T-wave abnormality?
Yes, you should see a cardiologist when having nonspecific T-wave abnormalities. Such changes need further examination as they can be signs of a disease. They can indicate, for example, myocardial edema or acute coronary syndrome [10, 9].
Do not worry about the diagnosis. The nonspecific T-wave changes can also be benign [10].
If you have been diagnosed with nonspecific T-wave abnormalities and experience chest pain or shortness of breath, you should see a doctor as soon as possible.