ECG Changes in Hyperkalemia

Hyperkalemia, or elevated potassium levels in the blood, can significantly affect the heart’s electrical activity, manifesting in distinct changes on an ECG. These changes range from early warning signs to patterns associated with cardiac arrest.

Common ECG Changes in Hyperkalemia

Peaked T waves: One of the earliest signs, these are tall, narrow, and tent-shaped T waves, often visible even with mild potassium elevation.
PR prolongation: Hyperkalemia delays atrioventricular (AV) conduction, widening the PR interval on the ECG.
Loss of P waves: In more severe cases, atrial depolarization is impaired, and P waves may disappear entirely.
Widened QRS complex: Due to slowed ventricular conduction, the QRS complex becomes broader, increasing the risk of arrhythmias.
ST segment changes: Severe hyperkalemia can cause ST elevation or depression, though these changes are often nonspecific.
Sine wave pattern: In extreme cases, the ECG takes on a sine wave appearance, indicating imminent cardiac arrest.
Ventricular arrhythmias: Progressive hyperkalemia may trigger life-threatening rhythms such as ventricular tachycardia or fibrillation.

It is critical to understand that the severity of ECG changes may not correlate linearly with serum potassium levels. Early detection and immediate treatment are vital, especially in patients with existing cardiac conditions.