Overview
The T wave on an ECG trace is indicative of ventricular repolarisation.
Look For
- A deflection following the QRS complex that is normally asymmetrical, with a slow upslope and a rapid downslope. Usually positive, though negative T waves are normal in aVR and V1.
T Wave Flattening
Look For
- Flat T waves with amplitude between +1mm to -1mm.
Causes of T Wave Flattening
- Myocardial ischaemia
- Hypokalaemia
Example
- ST depression, flattened T waves and prolonged QT interval associated with hypokalaemia:
T Wave Inversion
Look For
- Negative T waves with amplitude >1mm.
Causes of T Wave Inversion
- Myocardial ischaemia / infarctionNarrow, symmetric, 'coved' T wave inversion
- Physiological in children
- Pulmonary embolism
- Myocarditis
- Pericarditis
- Bundle branch block
- Left ventricular hypertrophy
- Hypertrophic cardiomyopathy
- Stroke
Tall T Waves
Look For
- T wave prominence. Note whether the T waves are symmetrical or asymmetrical.
Causes of Tall T Waves
- Hyperkalaemia
- Benign early repolarisation
- Myocardial infarction
Interpretation
- Narrow, symmetrical 'tented' T waves - suggestive of hyperkalaemia
- Tall T waves with concave ST elevation in the precordial leads - suggestive of benign early repolarisation
- Prominent, symmetrical and pointed ('hyperacute') T waves - suggestive of myocardial infarction
Example
- "Tented" T waves associated with mild hyperkalaemia:
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