What are the EKG findings in a patient with suspected hyperkalemia?

From the Guidelines

Hyperkalemia is characterized by specific EKG findings, including tall, peaked T waves, PR interval prolongation, P wave flattening, and QRS complex widening, which can progress to a sine wave pattern and ventricular fibrillation if left untreated, as noted in the 2021 study published in the Mayo Clinic Proceedings 1. The EKG changes associated with hyperkalemia are a result of the altered resting membrane potential of cardiac cells, affecting depolarization and repolarization.

• Early signs of hyperkalemia on EKG include:
  • Tall, peaked T waves, often the first and most sensitive finding, which are narrow-based and symmetrical, most prominently seen in precordial leads
  • PR interval prolongation
  • P wave flattening and eventual disappearance
• Progressive hyperkalemia leads to:
  • QRS complex widening, which may resemble a bundle branch block pattern
  • In severe cases, the QRS complex continues to widen and eventually merges with the T wave, creating a sine wave pattern - a pre-terminal rhythm that often precedes ventricular fibrillation and asystole The progression of these findings correlates roughly with serum potassium levels:
• Peaked T waves appear at levels >5.5 mEq/L
• PR prolongation and P wave changes at >6.5 mEq/L
• QRS widening at >7.0 mEq/L, as supported by the 2021 study in the Mayo Clinic Proceedings 1 and other studies, such as the 2017 update to practice standards for electrocardiographic monitoring in hospital settings 1. Recognizing these patterns is crucial as they may be the first indication of dangerous hyperkalemia requiring immediate treatment, as emphasized in the 2021 clinical management of hyperkalemia study 1 and the 2021 treatment options for the management of acute and chronic hyperkalemia study 1.

From the Research

EKG Findings in Hyperkalemia

The EKG findings in a patient with suspected hyperkalemia can be significant and potentially life-threatening. Some of the key EKG changes associated with hyperkalemia include:

• Peaked T waves
• Prolonged PR interval
• Widened QRS complex
• Flattened or absent P waves
• Sinus arrest or arrhythmias

Treatment and Management

According to 2, treatment of hyperkalemia includes measures to stabilize cardiac membranes, shift potassium from extracellular to intracellular stores, and promote potassium excretion. This can be achieved through the administration of calcium gluconate, beta-agonists, and intravenous insulin, as well as dialysis and the use of loop and thiazide diuretics.

Clinical Approach

As noted in 3, the initial clinical management of hyperkalemia involves deciding whether immediate treatment is required to avoid a life-threatening situation. This decision is often based on the presence of EKG changes and serum potassium concentration. The study suggests that absent or atypical EKG changes do not exclude the necessity for immediate intervention.

Key Considerations

Some key considerations in the management of hyperkalemia include:

• The use of calcium salts to stabilize cardiac membranes
• The administration of insulin and glucose to shift potassium into cells
• The use of beta-agonists, such as albuterol, to help lower potassium levels
• The importance of dialysis in removing excess potassium from the body
• The need for a long-term plan to prevent the recurrence or worsening of hyperkalemia, as discussed in 3