Objective To evaluate the effects of adenosine triphosphate (ATP) on the
antegrade conduction of atrioventricular node (AVN)
and their relationship. Methods Nineteen patients with preexcitation syndrome were involved who had received radiofrequency catheter ablation (RFCA) and whose
antegrade Wenckebach point of the AVN were above 150 beats per minute. Each had the followings measured: the antegrade Wenckebach point and 2:1
conduction point and the effective refractory period (ERP). Adenosine triphosphate was given intravenously at the time of atrium pacing until the dose of ATP reaches 0.30 mg/kg or the antegrade conduction of the AVN was blocked. Results The mean antegrade Wenckebach point of the AVN was 305.63±45.01 ms, the 2:1 antegrade conduction point was 262.63±24.55 ms and the mean antegrade ERP of the AVN was 235.78± 59.24 ms. The average dose of ATP needed to block the antegrade conduction of the AVN was 0.16± 0.057 mg/kg, totaling 11.4±4.53 mg. The antegrade Wenckebach point and 2:1 point of the AVN were negatively related to the dose of ATP needed to block the antegrade conduction of the AVN ( r = -0.797 , P <0.01; r =-0.699, P <0.01). The same was the antegrade ERP and the dose of ATP needed to block the antegrade conduction of the AVN ( r =-0.455, P <0.05). Conclusion The dose of ATP needed to block the antegrade conduction of the AVN was obviously related to the antegrade and the antegrade ERP of the AVN. That is, the better the antegrade conduction and the shorter the antegrade ERP of the AVN, the larger the dose of ATP needed to block its antegrade conduction.