What is the purpose of performing a vagal maneuver in SVT management?

• A. Slow AV nodal conduction
• B. Increase heart rate
• C. Dilate peripheral vessels
• D. Increase ventricular ectopy

Answer: (A)

Vagal maneuvers in SVT management work by boosting parasympathetic activity to slow conduction through the AV node. By increasing vagal tone, the AV nodal conduction velocity decreases and the nodal refractory period lengthens, which can disrupt a reentrant tachycardia that uses the AV node or simply reduce the ventricular rate enough to allow normal rhythm to resume. That’s why slowing AV nodal conduction is the intended effect. These maneuvers, such as the Valsalva maneuver or carotid sinus massage (when not contraindicated), are noninvasive first steps for stable narrow-complex SVTs. They won’t raise heart rate and aren’t reliably effective for rhythms that don’t depend on AV nodal conduction, and they must be used cautiously in patients with carotid disease or instability.