Which electrolyte imbalance is associated with increased sensitivity to digitalis toxicity?

Hypokalemia is associated with increased sensitivity to digitalis toxicity due to the critical role potassium plays in cardiac function, particularly in the action of digitalis (digoxin). Digitalis works primarily by inhibiting the sodium-potassium ATPase pump, which increases intracellular sodium and calcium levels, ultimately enhancing cardiac contractility. However, low levels of potassium in the body can exacerbate the effects of digitalis.

In a state of hypokalemia, there is less potassium available to compete with digitalis for binding sites on the sodium-potassium ATPase pump. This reduced competition increases the likelihood that digitalis will bind to the pump, leading to an enhanced pharmacological effect. Consequently, the risk of developing digitalis toxicity rises, manifesting as arrhythmias and other related symptoms.

This interaction highlights the importance of monitoring and managing potassium levels in patients on digitalis therapy to prevent potential toxicity.