AVRT tachycardia involves a reentrant circuit using an accessory pathway. which term best describes this?

• A. Macroreentry
• B. Microreentry
• C. Underspecified
• D. Adenosine-mediated

Answer: (A)

AVRT tachycardia is sustained by a reentrant loop that uses an accessory pathway to connect the atria and ventricles. This circuit travels around a relatively large portion of the heart’s conduction pathway, forming a large, circulating loop that includes the AV ring and the bypass tract. That makes it macroreentry—the reentrant mechanism spans a broad, spacious path rather than a tiny, localized circuit.

In contrast, microreentry would describe a very small reentrant circuit confined to a small area, which isn’t characteristic of AVRT. The idea of being adenosine-mediated refers to how some tachycardias respond to adenosine, not the size or nature of the reentrant circuit. So the best description for AVRT tachycardia is macroreentry.