VAV Response in AVNRT

During an electrophysiology (EP) study for typical AVNRT (Atrioventricular Nodal Reentrant Tachycardia), a VAV (Ventriculo-Atrial-Ventricular) response can be a crucial diagnostic finding.

What is a VAV response?

A VAV response occurs when a ventricular extrastimulus (a premature ventricular beat) is introduced during the tachycardia. This extrastimulus conducts retrogradely (backward) to the atrium, causing atrial activation (A). Subsequently, the atrium activates the ventricle again through the AV node, resulting in another ventricular activation (V).

Why is the VAV response important in AVNRT?

The VAV response helps diagnose AVNRT and differentiate it from other supraventricular tachycardias. In AVNRT, the VAV response typically demonstrates:

1. Retrograde conduction: The ventricular extrastimulus conducts backward to the atrium, indicating the presence of a retrograde pathway (usually the fast pathway).

2. Anterograde conduction: The subsequent atrial activation conducts down the slow pathway, resulting in another ventricular activation.

What does the VAV response indicate?

The VAV response indicates that the tachycardia is likely due to AVNRT, involving a reentrant circuit within the AV node. This response can help:

1. Confirm the diagnosis: The VAV response supports the diagnosis of AVNRT.

2. Guide ablation: The VAV response can help identify the target for ablation, typically the slow pathway.

The VAV response is a valuable diagnostic tool in EP studies, providing insights into the mechanism of AVNRT and guiding effective treatment.

#Electrophysiology

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