During AVRT, a HIS-refractory PVC will do what to the arrhythmia?

During AVRT, a HIS-refractory PVC will do what to the arrhythmia?

• A. Break the arrhythmia
• B. Prolong AVN conduction
• C. Accelerate AVRT
• D. Have no effect

Answer: (A)

AVRT is a reentrant circuit that depends on conduction through the ventricles, the AV node, and an accessory pathway to keep looping. If a ventricular premature beat occurs while the His-Purkinje system is refractory, that impulse cannot travel up through the AV node or participate in the reentrant loop. This disruption breaks the circuit and terminates the tachycardia. So a His-refractory PVC can stop AVRT rather than prolong conduction, accelerate the tachycardia, or have no effect.

AVRT is a reentrant circuit that depends on conduction through the ventricles, the AV node, and an accessory pathway to keep looping. If a ventricular premature beat occurs while the His-Purkinje system is refractory, that impulse cannot travel up through the AV node or participate in the reentrant loop. This disruption breaks the circuit and terminates the tachycardia. So a His-refractory PVC can stop AVRT rather than prolong conduction, accelerate the tachycardia, or have no effect.