Discordant U waves in the setting of hyperkalaemia

Area of Science:

• Cardiology
• Electrophysiology
• Medical Science

Background:

• U waves on an electrocardiogram (ECG) are typically associated with hypokalemia, often forming a TU complex.
• Physiological U wave genesis is theorized to involve late repolarization of Purkinje fibers or ventricular myocardial cells, or delayed afterdepolarizations.
• U waves generally resolve with hyperkalemia (high potassium levels).

Observation:

• This report details an atypical case where a patient presented with both hyperkalemia and discordant U waves.
• The patient had a history of chronic kidney disease, suggesting long-standing exposure to elevated potassium levels.

Findings:

• The coexistence of hyperkalemia and U waves in this case is unusual.
• A potential mechanism proposed is partial clinical adaptation of cardiac myocytes to chronic hyperkalemia.

Implications:

• This case challenges the established understanding of U wave behavior in hyperkalemic states.
• Understanding diverse U wave morphologies is crucial for accurate clinical interpretation in patients with electrolyte imbalances and kidney disease.