T-wave changes are vectorial changes on the ECG, which are usually an indicator of cardiac function. However, T-wave changes are not exclusively due to cardiac pathologies, but can be caused by a number of diseases, such as endocrine metabolic diseases and thyroid insufficiency. In addition, ionic disturbances, such as hypokalemia and hypocalcemia, may also cause changes in the T wave. T-wave changes may also occur in cases of organic heart disease, such as coronary artery disease, myocarditis, pericarditis, heart valve disease, congenital heart disease, and pulmonary heart disease. T-wave changes can also occur in cases of hypertension or cerebrovascular disease.