Effects Of Atrioventricular Accessory Pathway And Dual Atrioventricular Nodal Pathways On Right Atrial Electrophysiology

Objective:To evaluate the effects of atrioventricular accessory pathway(AP) and dual atrioventricular nodal pathways(DAVNP) on the electrophysiological characteristics of the right cardiac atrium by means of observation the changes of the atrial effective refractory period(ERP),ERP dispersion(ERPD) and the ability of induced-arrhythmia before and after radiofrequency catheter ablation(RFCA) treatment of paroxysmal supraventricular tachycardia(PSVT),to further discuss the clinical valve of these effects.Methods:Forty-two patients with paroxysmal supraventricular tachycardia(PSVT) but without documented paroxysmal atrial fibrillation(PAF) or atrial flutter(AFL) were included in the study.Patients were divided into two groups of DAVNP group and AP group based on the results of electrophysiological study(EPS).Twenty-three patients were included in the DANP group(8 men,15 women;mean age 48±12 years).Nineteen patients were Included in the DANP group(12 men,7 women;mean age 46±12 years).The slow AV nodal pathways modification was performed in the patients of DAVNP group and accessory pathway ablation was performed in the patients of AP group.Before and after radiofrequency catheter ablation,the patients were performed S₁S₂ and S₁S₁ scanning in high lateral right atrium(HRA),middle lateral right atrium(MRA),low lateral right atrium(LRA) to measure ERP,ERPD and to observe the changes of induced- arrhythmias.Results:Before ablation,seventeen patients were induced PAF or AFL in the forty-two patients,nine patients(6 men,3 women) in the AP group and eight patients(3 men,5 women) in the DAVNP group;after ablation,one patient can be induced PAF or AFL in each group. As compared to parameters before ablation,atrial ERP of the DAVNP group prolonged significantly in HRA(192.6±20.7msVS.202.2±19.5ms,P=0.001),MRA (177.0±21.0msVS.184.3±13.8ms,P=0.016),LRA(202.6±19.4msVS.211.7±19.7ms, P=0.007) and ERPD shortened significantly(30.0000±10.4447msVS.20.4348±6.3806ms,P=0.002);atrial ERP of the AP group prolonged significantly in HRA (191.6±16.8msVS.200.0±12.0ms,P=0.001),MRA(188.9±14.9ms VS.195.8±11.2ms, P=0.002),LRA(201.1±14.5msVS.208.4±12.1ms,P=0.015)and ERPD shortened significantly(28.9474±9.3659msVS.18.9474±8.0930ms,P=0.001).Before and after ablation,the changes of ERP and ERPD were no statistical significance in the two subgroups without induced-AF or induced-AFL(P＞0.05);whereas,the changes of ERP and ERPD have statistical significance in the two subgroups with induced-AF or induced-AFL(P＜0.05).There were no significant difference that the effects of DAVNP and AP on the different locations of the right atrium(P＞0.05).Conclusions:Successful ablation the DAVNP or AP can prolong significantly right atrial ERP of patients with DAVNP or AP,and furthermore,it can shorten significantly right atrial ERPD of these patients.The effects of DAVNP on ERPs in the different locations of right atrium are no difference with AP.The changes of ERP or ERPD were significant in the two subgroups with induced-AF or induced-AFL.After successful ablation,AF or AFL cannot be induced in most cases.Successful ablation treatment of DAVNP and AP may contribute to preventing the occurrence of AF and AFL.