Which electrolytes should be corrected to prevent and manage tachyarrhythmias?

• A. Potassium, magnesium, and calcium as appropriate.
• B. Sodium and phosphate.
• C. Potassium only.
• D. Calcium only.

Answer: (A)

Maintaining proper levels of key electrolytes is essential for stabilizing cardiac electrical activity and preventing tachyarrhythmias. Potassium sets the baseline for resting membrane potential and repolarization; imbalances can make heart cells more prone to abnormal rapid rhythms, so correcting potassium when it’s low or high is a fundamental step. Magnesium stabilizes myocardial membranes and modulates several ion channels, and IV magnesium is a cornerstone treatment for certain tachyarrhythmias, especially torsades de pointes or arrhythmias related to QT prolongation. Calcium influences the plateau phase of the cardiac action potential and helps regulate conduction; correcting abnormal calcium levels as indicated by the clinical picture can reduce arrhythmia risk. Because all three electrolytes can significantly impact how easily the heart shortens or lengthens its electrical cycles, they should be corrected as appropriate rather than focusing on any single one. Sodium disturbances and phosphate are less directly tied to tachyarrhythmia risk in most acute settings, so they aren’t the primary targets here.