Local reentry within the AV node causes which arrhythmia?

Local reentry within the AV node causes which arrhythmia?

• A. SVT
• B. Atrial fibrillation
• C. Ventricular tachycardia
• D. Nodal bradycardia

Answer: (A)

Local reentry within the AV node drives a fast, regular heart rhythm that stays supraventricular in origin. When the reentrant circuit is confined to the AV node, the ventricles are activated through the normal conduction system, producing a narrow-complex tachycardia. This pattern falls under the category of supraventricular tachycardia, specifically AV nodal reentrant tachycardia (AVNRT). Why the others don’t fit: atrial fibrillation is an irregular, disorganized atrial rhythm with variable AV conduction, not a single AV-node–based reentrant circuit. Ventricular tachycardia originates below the AV node in the ventricles. nodal bradycardia is a slow rhythm due to reduced nodal automaticity or conduction, not a rapid reentrant SVT.

Local reentry within the AV node drives a fast, regular heart rhythm that stays supraventricular in origin. When the reentrant circuit is confined to the AV node, the ventricles are activated through the normal conduction system, producing a narrow-complex tachycardia. This pattern falls under the category of supraventricular tachycardia, specifically AV nodal reentrant tachycardia (AVNRT).

Why the others don’t fit: atrial fibrillation is an irregular, disorganized atrial rhythm with variable AV conduction, not a single AV-node–based reentrant circuit. Ventricular tachycardia originates below the AV node in the ventricles. nodal bradycardia is a slow rhythm due to reduced nodal automaticity or conduction, not a rapid reentrant SVT.