What ECG changes are typically associated with hyperkalemia?

The changes on an ECG that are typically associated with hyperkalemia include peaked T waves, a widening of the QRS complex, and the potential development of sine wave patterns. As serum potassium levels increase, the electrical instability in the heart leads to characteristic changes.

Peaked T waves are one of the earliest signs of hyperkalemia and indicate altered repolarization of the ventricular myocardium. Following this, as potassium levels continue to rise, the QRS complex begins to widen because the conduction through the myocardium slows down, leading to a more prolonged depolarization period. In severe hyperkalemia, the ECG might display a sine wave pattern, which is a fusion of a widened QRS and peaked T waves, and can be indicative of impending ventricular fibrillation or asystole.

This specific pattern of peaked T waves, wide QRS complexes, and potential sine waves is critical for recognizing the severity of hyperkalemia and determining the need for emergent treatment, making it an important concept in critical care.