From the Guidelines
Hypokalemia is associated with characteristic EKG changes, including broadening of the T waves, ST-segment depression, and prominent U waves, and patients with severe hypokalemia should undergo immediate EKG monitoring to assess for potentially life-threatening arrhythmias. The EKG changes in hypokalemia are due to the crucial role of potassium in cardiac cell membrane potential and electrical conduction, and low potassium levels can alter the repolarization phase of cardiac action potentials, affecting the heart's electrical activity 1. Some of the key EKG findings in hypokalemia include:
- Broadening of the T waves
- ST-segment depression
- Prominent U waves
- Prolonged QT intervals
- PR interval prolongation
- Widening of the QRS complex It is essential to note that the severity of hypokalemia can be classified as mild (3.0–3.5 mEq/L), moderate (2.5–2.9 mEq/L), or severe (<2.5 mEq/L), and patients with severe hypokalemia are at a higher risk of developing potentially life-threatening arrhythmias, such as ventricular tachycardia, ventricular fibrillation, and torsades de pointes 1. Therefore, immediate EKG monitoring is recommended for patients with severe hypokalemia to assess for potentially life-threatening arrhythmias and to guide appropriate treatment.
From the Research
EKG Changes in Hypokalemia
- Hypokalemia can cause various EKG changes, including dynamic changes in T-wave morphology, ST-segment depression, and U waves, which are often best seen in the mid-precordial leads (V2–V4) 2.
- The PR interval can also be prolonged along with an increase in the amplitude of the P wave in patients with hypokalemia 2.
- EKG changes are one of the valuable diagnostic clues for recognizing hypokalemia, and monitoring EKG is essential for patients at risk of hypokalemia 3.
Management of Hypokalemia
- Management of hypokalemia consists of intravenous potassium replacement during cardiac monitoring for patients with marked symptoms, ECG abnormalities, or severe hypokalemia (ie, level less than 3.0 mEq/L) 4.
- Oral replacement is appropriate for asymptomatic patients with less severe hypokalemia 4.
- It is proposed to elevate potassium in asymptomatic patients with lower normal concentrations and concurrent cardiovascular disease 5.