During AVNRT, RV pacing entrainment typically yields which response?

• A. VAV or VAHV
• B. AV Dissociation
• C. Progressive PR Shortening
• D. No Effect

Answer: (A)

Entrainment during AVNRT from the ventricle shows that the ventricle can reset a reentrant circuit that resides in the AV node. The paced ventricular beat conducts retrogradely up the reentry pathway to activate the atria, and then the circuit resumes with the next ventricular activation. This creates a predictable sequence where a ventricular beat is followed by atrial activation, and then the next ventricular activation—often described as a VAV pattern. If the retrograde impulse also reaches the His bundle before the next ventricular activation, you can see a VAHV sequence as well. These patterns—VAV or VAHV—are classic signs that the tachycardia is AVNRT and that the ventricle is entraining the circuit.