Final answer:
When using antiarrhythmics, monitoring of electrolytes, especially potassium, is essential as it plays a critical role in cardiac rhythm and can lead to severe arrhythmias if imbalanced.
Step-by-step explanation:
When administering antiarrhythmics, it is crucial to monitor key electrolytes such as potassium, sodium, and calcium due to their roles in maintaining cardiac rhythm and nerve impulse conduction. Potassium is particularly important as both hypokalemia (low potassium levels) and hyperkalemia (high potassium levels) can lead to serious cardiac arrhythmias, where the heart muscle becomes weak and can ultimately fail. Therefore, regulating potassium levels is vital when treating patients with antiarrhythmic drugs.