Which statement best describes global reentry?

• A. Involves conduction between atria and ventricles leading to SVT
• B. Involves conduction within the SA node only
• C. Occurs only in the ventricles
• D. Only affects atrial tissue

Answer: (A)

Global reentry is a looping reentrant circuit that spans both atrial and ventricular tissue, creating a pathway that conducts from the atria into the ventricles and back to the atria. This setup sustains a rapid rhythm classified as a supraventricular tachycardia because the circuit uses an atrioventricular relationship rather than being confined to a single chamber. The description involving conduction between the atria and ventricles best captures this cross-chamber loop. In contrast, a circuit restricted to the SA node would be a nodal phenomenon, a circuit only in the ventricles would be ventricular reentry, and one that affects only atrial tissue would not involve the ventricles at all.