The Evaluation Of Function Of Slow Pathway With Atrial Incremental Pacing

Objective To evaluate the value of atrial incremental pacing in determining whether the slow pathway is ablated.Methods Twenty-eight consecutive patients with classic atrioventricular nodal(AVN) reentrant tachycardia(AVNRT) undergoing ablation using the slow pathway approach were included, seven males and twenty-one females, with average age of 53 16 years old. After each radiofrequency application with an episode of junctional rhythm, the maximal AH interval during atrial incremental pacing(AHmax) and programmed extrastimulus(A2H2max), Wenckebach cycle length (Wen) , antegrade effective refractory period of AVN ( AVN ERP ) and fast pathway (FP ERP), and tachycardia cycle length (AHt) were compared with those before ablation without using isoprenaline. At the same time, inducibility of tachycardia and diagnosis of dual atrioventricular nodal pathways were compared between the two kinds of stimulus methods.Results Twenty-six patients(92.9%) were induced AVNRT with atrial incremental pacing, nineteen patients(67.9%) were induced AVNRT and nineteen patients(67.9%) were induced jump with atrial programmed extrastimulus. AHmax (286 ± 73 vs 160±54ms, p<0.01) and A2H2max'(321 ±98 vs 232 ± 65ms, p<0.01) shortened significantly, while Wen'(324±55 vs 358 ±57ms, p<0.01) and FP AVN'(242± 32 vs 278±60ms, P<0.01) increased significantly, irrespective of whether the slow pathway remained or not.Conclusions Atrial incremental pacing is a kind of safe and reliable method in evaluating AVN funtion, compared with classic atrial programmed extrastimulus, and can be conveniently used to determine whether the slow pathway is ablated or not during ablation.