Typical ECG changes in patients with hyperkalemia include the following: 1. Tent-like T waves, which are manifested by symmetry between the high apical ascending and descending branches of the T wave and basal narrowing, when the blood potassium is mostly between 5.5 and 7.5 mmol/L and is accompanied by a shortened QT interval. This typical T-wave change is seen in only about a quarter of cases. In the case of children and adolescents, a change from inverted to upright T waves in leads V1-V3 in the presence of combined hyperkalemia can be seen. In children and adolescents, a change from inverted to upright T waves can be seen in V1-V3 leads in combination with hyperkalemia, and in left ventricular hypertrophy in combination with hyperkalemia. 2. The patient may have arrhythmias such as sinus bradycardia, junctional rhythm, intra-atrial, atrioventricular and intraventricular conduction block, sinus rest, and occasionally ventricular tachycardia and ventricular fibrillation may be seen.