Digitalis toxicity can cause
**Core Concept**
Digitalis toxicity occurs when there is an excessive level of digitalis glycosides, such as digoxin, in the body. This can lead to **cardiac arrhythmias** and other systemic effects due to the drug's mechanism of action on the **sodium-potassium ATPase pump**.
**Why the Correct Answer is Right**
The correct answer choice is related to the effects of digitalis toxicity on the heart. Digitalis toxicity can cause various **cardiac arrhythmias**, including atrial tachycardia with atrioventricular (AV) block, premature ventricular contractions (PVCs), and ventricular tachycardia.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because while digitalis is used to treat heart failure and certain arrhythmias, its toxicity does not typically cause an improvement in cardiac function.
**Option B:** This choice is incorrect as digitalis toxicity does not typically lead to a decrease in potassium levels, although hypokalemia can increase the risk of digitalis toxicity.
**Option C:** This choice is incorrect because digitalis toxicity can cause a range of arrhythmias but is not typically associated with a normal heart rhythm.
**Option D:** This choice is incorrect as it is not directly related to the primary effects of digitalis toxicity on the heart.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that digitalis toxicity can be precipitated by **hypokalemia**, **hypomagnesemia**, or **hypercalcemia**, and its diagnosis should be considered in patients taking digitalis glycosides who present with new arrhythmias or other symptoms.
**Correct Answer:** D. Cardiac arrhythmias.