Global reentry is between which chambers and can cause SVT?

• A. Between atria and ventricles
• B. Within AV node
• C. Between ventricles and septum
• D. Within right atrium

Answer: (A)

Global reentry refers to a macro-reentrant circuit that spans both atrial and ventricular tissue via an accessory pathway, creating AV reciprocating tachycardia. In this setup, the impulse travels from the atrium to the ventricle through the accessory pathway and returns to the atrium retrogradely through the AV node or His-Purkinje system, forming a loop that involves both chambers. This is why the mechanism is described as between the atria and ventricles.

Reentry confined to the AV node would be an intranodal AVNRT, not a circuit between chambers. A reentry localized to the ventricles and septum would be a ventricular/septal circuit, not a typical atrioventricular reentrant tachycardia. Reentry within the right atrium alone would involve atrial tissue only, such as atrial flutter or focal atrial tachycardia, and would not be an AVRT-type SVT.