**Core Concept:** Paroxysmal supraventricular tachycardia (PSVT) is a type of rapid heart rhythm that originates from the sinoatrial (SA) node or the atrioventricular (AV) node. PSVT can be categorized into three main types: atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and accessory pathway-related PSVT (AP-PSVT).

**Why the Correct Answer is Right:**

The correct answer is D: beta-blockers. Beta-blockers, particularly those that have intrinsic sympathomimetic activity (ISA) like isoproterenol, are used to terminate PSVT due to their ability to suppress the atrioventricular (AV) node reentrant circuit, thereby slowing down the heart rate and preventing the reentry mechanism. They act on beta-1 receptors primarily, but their ISA property also helps to reduce the refractory period of the AV node, making it more susceptible to conduction block.

**Why Each Wrong Option is Incorrect:**

A) Calcium channel blockers, such as verapamil or diltiazem, are not effective in treating PSVT due to their lack of ISA property, which is crucial for suppressing the reentry circuit in AV node.

B) Antiarrhythmic drugs like amiodarone or sotalol are not preferred for PSVT treatment because they can cause prolongation of the AV conduction time and are less effective in suppressing the reentry circuit.

C) Electrical cardioversion is a procedure used to restore sinus rhythm in cases of atrial fibrillation or atrial flutter, not PSVT. While electrical cardioversion can be an option for atrial fibrillation, it is not suitable for PSVT due to the different underlying mechanisms and arrhythmia types.

**Clinical Pearl:** In cases of PSVT, pharmacological therapy is usually the preferred approach before considering invasive interventions such as electrical cardioversion or catheter ablation. It is essential for medical students and practitioners to know the appropriate medications for various arrhythmias to ensure safe and effective patient management.