Which ECG finding is indicative of hyperkalemia?

Peaked T waves are a classic finding on an electrocardiogram (ECG) that indicates hyperkalemia, which is an elevated level of potassium in the blood. As potassium levels rise, it affects the cardiac myocytes' depolarization and repolarization processes. The increase in extracellular potassium concentration causes the resting membrane potential to become less negative, thereby altering the repolarization phase of the action potential. One of the most noticeable changes is the appearance of T waves that become taller and more pointed.

The morphology of peaked T waves can vary, but they are typically described as being narrow and symmetric compared to the more common T wave shapes observed in normal ECGs. This is particularly important in emergency medicine as recognizing these changes is critical for prompt diagnosis and management of hyperkalemia, which can lead to life-threatening arrhythmias if not addressed rapidly.

Other ECG changes do occur with hyperkalemia as potassium levels continue to rise, but the presence of peaked T waves is one of the initial and most characteristic findings. Understanding these changes is essential for healthcare providers working in emergency settings, as they need to quickly interpret ECGs to guide treatment for patients with suspected electrolyte imbalances.