T wave
Also calledT-wave
Definition
The deflection following the QRS complex that represents ventricular repolarization (the rapid repolarization phase of the ventricular action potential). In adults it is normally upright in leads I, II and V3 to V6 and in most other leads, always inverted in aVR, and may be upright or inverted in aVL, III and V1. A normal T wave is asymmetric, rising more slowly than it falls. Abnormal T waves (for example peaked, symmetrical, flat or inverted) can reflect ischemia, electrolyte disturbance (hyperkalemia classically produces tall, symmetrical, narrow-based T waves) or other repolarization abnormalities.
Sources
- Rautaharju PM, Surawicz B, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval. Circulation. 2009;119(10):e241-e250. doi.org/10.1161/CIRCULATIONAHA.108.191096
- Samesima N, God EG, Kruse JCL, et al. Brazilian Society of Cardiology guidelines on the analysis and issuance of electrocardiographic reports - 2022. Arq Bras Cardiol. 2022;119(4):638-680. doi.org/10.36660/abc.20220623
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.