What is the role of ECG in the diagnosis of hypokalemia (low potassium level)?

Updated: Dec 06, 2018
  • Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Perform an ECG to determine whether the hypokalemia is affecting cardiac function or to detect digoxin toxicity. The ECG may show atrial or ventricular tachyarrhythmias, decreased amplitude of the P wave, or appearance of a U wave.

ECG monitoring is imperative for severe hypokalemia (< 2 mEq/L in otherwise healthy individuals or < 3 mEq/L in patients with known or suspected cardiac disease). With a sudden shift of potassium into the cells (eg, with insulin therapy for diabetic ketoacidosis), even individuals with healthy hearts can develop lethal arrhythmias. Continuously monitor patients on digoxin or those with digoxin toxicity.

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