In cases of hyperkalemia, what effects are typically seen on the ECG?

In the context of hyperkalemia, the ECG typically exhibits specific changes that reflect the effect of elevated potassium levels on cardiac conduction. The presence of peaked T waves is a characteristic finding in hyperkalemia, as elevated potassium leads to increased cardiac excitability and alters the repolarization phase of the cardiac cycle. This results in T waves that are taller and more pointed than normal.

Additionally, as hyperkalemia progresses, there is a widening of the QRS complex due to the slowing of conduction through the ventricles. This widening occurs because high potassium levels affect the sodium channels, which are essential for rapid depolarization during the action potential. When the QRS complex widens, it indicates a delay in ventricular depolarization and can progress to a complete block or even ventricular fibrillation if the hyperkalemia is severe.

The combination of peaked T waves and a widening QRS complex serves as a critical indication of hyperkalemia on an ECG and is crucial for prompt diagnosis and treatment to prevent life-threatening arrhythmias.