From the Guidelines
The normal elevation for a T wave on an ECG is typically less than 1.0 mV in leads V2 to V6, with the T-wave amplitude being most positive in lead V2 or V3, as reported in the 2009 American Heart Association recommendations 1. When evaluating T-wave elevation, it's crucial to consider the lead and individual characteristics, as the normal T-wave amplitude varies by age, gender, and race.
- In adults 20 years old and older, the normal T wave is inverted in aVR; upright or inverted in leads aVL, III, and V1; and upright in leads I and II and in chest leads V3 through V6.
- The T-wave amplitude in limb leads is influenced by the frontal-plane T axis, which in turn is influenced by the QRS axis.
- T-wave amplitudes for V2 from 1.0 to 1.4 mV have been listed as upper normal thresholds in men (up to 1.6 mV in the 18- to 29-year age group) and from 0.7 up to 1.0 mV in women, as stated in the study 1. The interpretation of isolated T-wave abnormalities can be challenging, and it's essential to consider the clinical context and compare with previous ECGs when available to avoid inaccurate diagnoses of myocardial ischemia and infarction.
- The T wave may be called low when its amplitude is less than 10% of the R-wave amplitude in the same lead and as flat when the peak T-wave amplitude is between 0.1 and 0.1 mV in leads I, II, aVL, and V4 to V6, as proposed in the 2009 recommendations 1.
From the Research
Normal Elevation for T Wave on ECG
- The normal elevation for the T wave on an electrocardiogram (ECG) is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, study 5 mentions that T-wave amplitudes were automatically measured in 12-lead ECGs of patients presenting with acute chest discomfort, and the performance for lead-specific 95th-percentile thresholds were reported as likelihood ratios, specificity, and sensitivity.
- The study 5 found that in most leads, T-wave amplitudes tended to be greater in patients without myocardial infarction than those with myocardial infarction.
- Study 4 proposed new ECG criteria for strictly posterior myocardial infarction, including T-wave criteria, but does not provide information on normal T-wave elevation.
T-Wave Abnormalities
- T-wave abnormalities are common during the acute phase of non-ST-segment elevation acute coronary syndromes 2.
- Isolated T-wave abnormality was significantly more prevalent in edema-positive versus edema-negative subjects 2.
- T-wave abnormalities in the setting of non-ST-segment elevation acute coronary syndromes are related to the presence of myocardial edema 2.
- Hyperacute T waves, when defined as increased T-wave amplitude exceeding the 95th percentile, did not provide useful information in diagnosing myocardial infarction in the sample studied 5.