Ablation and procedure endpoints
Three-dimensional electro-anatomical mapping systems (Carto 3, Biosense
Webster, Diamond Bar, CA, US and Ensite NAVX, Abbott, Minneapolis, MN,
US) were used for these procedures. Temperature-controlled ablation
catheters (Navistar, Biosense Webster, Diamond Bar, CA, US and Safire,
Abbott, Minneapolis, MN, US) were applied (55-60°C, 40-50 W, 90-120
seconds). The ablation targets located on the AV nodal slow pathway
area, within the lower one third of the triangle of Koch.
If the patients had passed EPS after initial ablation without any
evidence of AP, they then underwent an adenosine triphosphate (ATP)
test. Ventricular backup pacing by the RVA catheter was ready for
protection against slow ventricular rhythm during the ATP test. An ATP
bolus of 30 mg was then injected rapidly via peripheral vein to block
the AV node. When AV nodal block was observed without antegrade A-V
nodal conduction nor pre-excitation, ventricular pacing was further
performed to exclude retrograde V-A conduction via a concealed AP. The
procedure was concluded after confirmation by both EPS and the ATP test.