**Core Concept**
Paroxysmal supraventricular tachycardia (PSVT) is a type of abnormal heart rhythm originating from the atria or the atrioventricular (AV) node. The goal of treatment is to restore a normal sinus rhythm and prevent recurrence.

**Why the Correct Answer is Right**
Adenosine is the current drug of choice for PSVT due to its high efficacy and safety profile. It works by transiently blocking AV nodal conduction, thereby interrupting the re-entrant circuit and allowing the heart to revert back to a normal sinus rhythm. Adenosine has a very short half-life, which makes it ideal for acute treatment of PSVT.

**Why Each Wrong Option is Incorrect**
* **Option A:** Digoxin is a cardiac glycoside that increases the force of contraction and slows the heart rate. However, it is not indicated in PSVT as it can actually worsen the condition by increasing the frequency of atrial contractions.
* **Option B:** Verapamil is a calcium channel blocker that can slow the heart rate and is sometimes used to treat PSVT. However, it is not the first-line treatment and is usually reserved for patients who are refractory to adenosine.
* **Option C:** Amiodarone is an anti-arrhythmic medication that is used to treat a variety of cardiac arrhythmias. However, it is not typically used as a first-line treatment for PSVT due to its side effect profile and the availability of more effective and safer alternatives.

**Clinical Pearl / High-Yield Fact**
Adenosine is a potent vasodilator and can cause transient flushing and chest discomfort due to its effects on the AV node and coronary arteries.

**Correct Answer:** A. Adenosine.