What is the drug of choice to control supraventricular tachycardia-
## Core Concept
The question tests the management of supraventricular tachycardia (SVT), a type of abnormal heart rhythm that originates above the ventricles. The goal is to identify the most appropriate drug for controlling SVT. Pharmacological management often involves agents that can either terminate the acute episode or prevent recurrence by controlling the heart rate.
## Why the Correct Answer is Right
Adenosine is considered the drug of choice for acute termination of SVT due to its effectiveness and safety profile. It works by transiently blocking AV node conduction, which can interrupt the re-entrant circuit responsible for SVT. Adenosine has a very short half-life, which reduces the risk of prolonged side effects. Its rapid onset and short duration of action make it ideal for acute management.
## Why Each Wrong Option is Incorrect
- **Option A:** While beta blockers can be used to control the ventricular rate in SVT, they are not the first choice for acute termination of SVT.
- **Option B:** Calcium channel blockers, such as verapamil or diltiazem, can also terminate SVT by blocking AV node conduction but are typically considered after adenosine if it is not available or contraindicated.
- **Option D:** Digoxin can be used for rate control in atrial fibrillation and some types of SVT but is not the first-line treatment for acute termination of SVT.
## Clinical Pearl / High-Yield Fact
A key point to remember is that adenosine should be administered as a rapid bolus injection followed by a saline flush to ensure it reaches the heart quickly and effectively. A classic presentation for SVT is a patient with sudden onset palpitations, and the immediate use of adenosine can both diagnose and treat the condition.
## Correct Answer: C. Adenosine