What is the drug of choice for SVT?

• A. Atropine
• B. Amiodarone
• C. Lidocaine
• D. Adenosine

Answer: (D)

Adenosine is the go-to drug for acute termination of stable SVT because it briefly blocks conduction through the AV node, which is often the pathway sustaining the reentrant tachycardia. Its action is extremely short-acting—only a few seconds—so given as a rapid IV push with a saline flush, it can stop the tachycardia and reset the heart to a normal rhythm with minimal overall effect. If the first dose doesn’t terminate the rhythm, a second dose can be given, but you monitor for a brief pause in rhythm and potential side effects like chest discomfort, flushing, or bronchospasm. This drug isn’t appropriate for patients with high-grade AV blocks or sick sinus syndrome without a pacemaker, and it can worsen bronchospasm in someone with asthma. It won’t treat tachyarrhythmias that don’t depend on AV nodal conduction, such as ventricular tachycardia, and while it can reveal underlying rhythm in atrial fibrillation, it does not terminate AF with RVR.