What is the recommended acute treatment for a narrow complex supraventricular tachycardia?

What is the recommended acute treatment for a narrow complex supraventricular tachycardia?

• A. Vagal Stimulation
• B. Cardizem (Diltiazem)
• C. Adenosine 6 mg Push
• D. Propranolol

Answer: (C)

Adenosine works best for acute termination of a stable narrow-complex SVT because the tachycardia in these cases usually depends on conduction through the AV node. Adenosine briefly blocks AV nodal conduction, interrupting the reentrant circuit and allowing the heart to reset to a normal rhythm. Its effect is rapid and short-lived, so a rapid IV push can terminate the tachycardia quickly with minimal lasting disturbance. Dosing is a rapid 6 mg IV bolus, followed by a saline flush; if there’s no response, a second dose of 12 mg can be given. This approach is favored in the acute setting over longer-acting agents like diltiazem or propranolol, which can slow the heart more gradually and carry more hemodynamic risk in a short window. Vagal maneuvers can be tried as well, but they’re less reliable for immediate termination than adenosine.

Adenosine works best for acute termination of a stable narrow-complex SVT because the tachycardia in these cases usually depends on conduction through the AV node. Adenosine briefly blocks AV nodal conduction, interrupting the reentrant circuit and allowing the heart to reset to a normal rhythm. Its effect is rapid and short-lived, so a rapid IV push can terminate the tachycardia quickly with minimal lasting disturbance.

Dosing is a rapid 6 mg IV bolus, followed by a saline flush; if there’s no response, a second dose of 12 mg can be given. This approach is favored in the acute setting over longer-acting agents like diltiazem or propranolol, which can slow the heart more gradually and carry more hemodynamic risk in a short window. Vagal maneuvers can be tried as well, but they’re less reliable for immediate termination than adenosine.