**Core Concept:**
Tall peaked T waves on an electrocardiogram (ECG) are a sign of increased action potential duration (APD) in the ventricles. This may indicate conditions like long QT syndrome, hyperkalemia, or certain medications. In these situations, the T wave is prolonged and elevated due to the delayed repolarization phase.

**Why the Correct Answer is Right:**
The correct answer, Digitalis, is a medication that increases the action potential duration in the ventricles by inhibiting the sodium-potassium ATPase pump in the sarcoplasmic reticulum. This leads to a prolonged repolarization phase and elevated T waves on an ECG.

**Why Each Wrong Option is Incorrect:**

A. Beta-blockers are used to decrease heart rate and contractility but do not directly alter the APD or T wave morphology. Hence, they are not the correct answer.

B. Calcium channel blockers (CCBs) also do not directly affect the APD and T wave morphology, making this option incorrect.

C. Antiarrhythmic agents like Class III antiarrhythmics (e.g., Sotalol) are designed to correct abnormal repolarization patterns. However, in this case, Digitalis is a better choice because it directly affects the APD.

D. Diuretics like Furosemide are used to treat fluid overload and edema, not specifically T wave abnormalities. Hence, this option is incorrect.

**Core Concept:**
Tall peaked T waves on an ECG indicate increased APD or delayed repolarization in the ventricles. This can result from various conditions or medications.

**Why Each Wrong Option is Incorrect:**

A. Beta-blockers, CCBs, antiarrhythmic agents like Class III antiarrhythmics, and diuretics are all incorrect because they do not directly affect the APD or T wave morphology.

**Clinical Pearl:**
When evaluating ECG abnormalities, consider the cause of prolonged APD and repolarization delay: medications like Digitalis, electrolyte imbalances (e.g., hyperkalemia), or inherited disorders (e.g., long QT syndrome). These can lead to tall peaked T waves on an ECG.

**Correct Answer Explanation:**
Digitalis is the appropriate treatment for tall peaked T waves on an ECG because it directly affects the APD by inhibiting the sodium-potassium ATPase pump in the sarcoplasmic reticulum, slowing repolarization and prolonging the T wave. This approach is known as "calcium-induced repolarization."