Appliance of SV/SS Ratio During Rapid Atrial Pacing for the Slow Pathway Ablation on Slow-Fast Atrioventricular Nodal Reentrant Tachycardia.

The purpose of the study is to evaluate SV/SS ratio during rapid atrial pacing for the slow pathway ablation on slow fast atrioventricular nodal reentrant tachycardia(AVNRT).The patients were devided into two groups.Group Ⅰ included ten patients with AVNRT and continuous atrioventricular nodal function curves,group Ⅱ included seventeen patients with AVNRT and discontinuous AV nodal function curves.The SV and SS intervals were measured during rapid atrial pacing at the maximum rate with consistent 1∶1 atrioventricular conduction.SV intervals of all patients shortened after slow pathway ablation(group Ⅰ:221.0±22.3 vs 357.0±43.7 ms,group Ⅱ:202.1±30.6 vs 379.4±44.2 ms, P 0.05 respectively).All the SV/SS ratio exceeded 1.0 before ablation and 1 after ablation no matter in which group.Conclusion:The SV/SS ratio can be determined as one of the assistant end points of slow pathway ablation on AVNRT.This finding may be particularly useful in patients with inducible AV nodal reentry without dual AV nodal physiology on atrial extrastimulus testing.