Abstract 14156: Utility of Pre-Induction Ventriculoatrial Response to Adenosine in the Diagnosis of Orthodromic Reciprocating Tachycardia
Introduction: Adenosine is known to consistently block AV nodal conduction in anterograde and retrograde directions.
Hypothesis: We hypothesized that persistent ventriculoatrial (VA) despite administration of adenosine would have a high predictive value for identifying the presence of a retrograde accessory pathway (AP) and associated orthodromic reciprocating tachycardia (ORT).
Methods: One hundred and sixty-eight patients undergoing electrophysiology study for supraventricular tachycardia (SVT) had assessment of VA conduction during ventricular pacing with adenosine administration. Standard pacing maneuvers were then used for induction and diagnosis of SVT mechanism.
Results: Absence of VA block to adenosine (doses up to 24 mg) had an 88% sensitivity and 91% specificity for identifying ORT (positive predictive value 76%, negative predictive value 96%). Four patients with adenosine-induced VA block and inducible ORT had decremental APs. Adenosine caused VA block in all 6 patients with eccentric VA activation due to atypical AV nodal conduction, and concentric VA conduction persisted in all 12 patients with a septal AP. Adenosine unmasked free-wall APs in 10 patients by blocking AV nodal conduction and shifting baseline concentric VA activation to eccentric.
Conclusions: The response of VA conduction to adenosine is a highly sensitive and specific method for detecting retrograde AP conduction and inducible ORT. VA block with adenosine nearly rules out inducible ORT. The effect is particularly helpful in cases of VA fusion, where adenosine block of AV nodal conduction can delineate the location of the AP atrial insertion site.
Author Disclosures: C. Liu: None. J. Ip: None. J. Cheung: None. G. Thomas: None. S. Markowitz: None. B. Lerman: None.
- © 2016 by American Heart Association, Inc.