A non-specific T-wave abnormality is a change in the normal T-wave pattern often associated with hyperventilation, hot or cold beverage consumption, abrupt changes in position or nervous disorders, such as anxiety. Some medical conditions that may cause T-wave abnormalities include athletic heart syndrome, hyperkalemia, hypokalemia and ischemia.
Repolarization is the process by which the heart's electrical system recharges during heartbeat intervals. The electrical impulses that are generated with each heartbeat can be detected using an electrocardiogram, also known as ECG or EKG. Five distinct waves can be recorded on an ECG, which are labeled P, Q, R, S and T. The T-wave is the repolarization of the heart's ventricles.
A normal T-wave is characterized by a vertical line in all leads, excluding aVR and V1, an amplitude of less than 5 millimeters in limb leads and an amplitude of less than 15 millimeters in precordial leads. Typically, changes in the normal T-wave pattern are considered to be non-specific. Abnormalities in T-waves can be classified into five categories: inverted, hyperacute, biphasic, flattened or "camel hump."
Inverted T waves often occur with athletic heart syndrome, raised intracranial pressure and pulmonary embolism. Disorders of the central nervous system that are linked to inverted T waves are uncommon.
Hyperacute T waves are associated with Prinzmetal angina, while biphasic T waves are characteristic of myocardial ischemia and hypokalemia. Flattened T waves may indicate ischemia or electrolyte abnormality, while camel hump T waves may represent heart block.