AVRT is a type of tachycardia described as macroreentrant.

AVRT is a type of tachycardia described as macroreentrant.

• A. Macroreentrant
• B. Focal automatic
• C. Triggered
• D. Atrial fibrillation

Answer: (A)

Macroreentry describes a large looping activation that travels around a circuit, using two separate pathways. In AVRT the tachycardia is sustained by a boundless loop that includes the AV node and an accessory pathway, creating a continuous circuit that spans both atrial and ventricular tissue. The impulse can travel anterograde through the AV node and retrograde through the accessory pathway (or the reverse), so the wavefront keeps re-entering the circuit and driving a rapid rhythm. This is distinct from focal automatic tachycardia, which comes from a single ectopic focus with its own spontaneous pacemaker activity, not a fixed reentrant loop. Triggered tachycardia results from afterdepolarizations that trigger beats rather than a circulating circuit. Atrial fibrillation involves numerous disorganized, rapid atrial activations from multiple foci and microreentrant waves, not a single organized macroreentrant loop.

Macroreentry describes a large looping activation that travels around a circuit, using two separate pathways. In AVRT the tachycardia is sustained by a boundless loop that includes the AV node and an accessory pathway, creating a continuous circuit that spans both atrial and ventricular tissue. The impulse can travel anterograde through the AV node and retrograde through the accessory pathway (or the reverse), so the wavefront keeps re-entering the circuit and driving a rapid rhythm.

This is distinct from focal automatic tachycardia, which comes from a single ectopic focus with its own spontaneous pacemaker activity, not a fixed reentrant loop. Triggered tachycardia results from afterdepolarizations that trigger beats rather than a circulating circuit. Atrial fibrillation involves numerous disorganized, rapid atrial activations from multiple foci and microreentrant waves, not a single organized macroreentrant loop.