From the Guidelines
Hyperkalemia is associated with characteristic EKG changes, including peaked T waves, PR interval prolongation, and QRS complex widening, which can progress to a sine wave pattern and lead to ventricular fibrillation or asystole, as noted in the most recent study by 1. The EKG changes associated with hyperkalemia are a result of the excess extracellular potassium altering the resting membrane potential of cardiac cells, initially increasing repolarization speed and eventually slowing depolarization.
- Early changes include tall, peaked T waves (typically seen when potassium exceeds 5.5 mEq/L), which are narrow-based and symmetrical, most prominent in precordial leads.
- As potassium levels rise further (>6.5 mEq/L), PR interval prolongation occurs, followed by P wave flattening and eventual disappearance.
- With severe hyperkalemia (>7 mEq/L), QRS complexes widen, creating a sine wave pattern that can lead to ventricular fibrillation or asystole, as described in the study by 1. The management of hyperkalemia involves urgent treatment with calcium gluconate, insulin, and glucose to stabilize cardiac membranes and shift potassium intracellularly, as recommended in the study by 1.
- Calcium gluconate (1-2 ampules IV) is used to stabilize cardiac membranes and reduce the risk of cardiac arrhythmias.
- Insulin with glucose (10 units regular insulin with 25g dextrose IV) is used to shift potassium intracellularly and reduce serum potassium levels.
- Sodium bicarbonate (50 mEq IV) may be used if acidosis is present to promote potassium excretion, as noted in the study by 1. These measures provide temporary stabilization while definitive treatments like dialysis or potassium-binding resins address the underlying hyperkalemia, as described in the study by 1.
From the Research
EKG Changes Associated with Hyperkalemia
- The electrocardiogram (ECG) can be a crucial diagnostic tool in identifying patients with potentially lethal hyperkalemia 2
- Peaking of the T waves is a widely recognized ECG sign of hyperkalemia, although it is rarely a manifestation of life-threatening hyperkalemia 2
- Other ECG changes associated with hyperkalemia include main rhythm disorders, such as arrhythmias, and non-rhythm disorders, such as changes in ECG parameters 3
- Hyperkalemia with potassium levels more than 6.5 mEq/L or EKG changes is considered a medical emergency and requires prompt treatment 4
Treatment and EKG Changes
- Calcium gluconate is commonly used to stabilize cardiomyocyte membranes and prevent cardiac conduction disturbances in patients with hyperkalemic ECG changes 4, 3, 5
- IV Ca-gluconate therapy has been shown to be effective in improving main rhythm disorders due to hyperkalemia, but not non-rhythm ECG disorders 3
- Other treatments for hyperkalemia, such as insulin, glucose, and beta-2 agonists, can help lower serum potassium levels and improve ECG changes 4, 6, 5