隐匿性拖带时起搏后间期与慢径消融成功靶点的关系

评价应用隐匿性拖带方法对准确靶点消融的有效性及探讨常规慢径靶点部位与房室结折返性心动过速(AVNRT)折返环的关系。可反复诱发的持续性典型AVNRT的患者 34例 ,消融导管在后或中间隔标测到A/V≤ 0 .5处 ,然后诱发心动过速 ,在高位右房 (HRA)和冠状窦口 (CSO)超速起搏产生隐匿性拖带 ,并按常规方法进行慢径消融。比较隐匿性拖带时靶点部位起搏后间期与心动过速周长的差值 (PPI-TCL值 )在成功靶点与不成功靶点区别。结果 :HRA超速起搏发生隐匿性拖带时 ,His束记录部位A波均为逆向夺获。而CSO超速起搏拖带时 ,32例His束记录部位A波为顺向夺获 ,另 2例为逆向夺获。在这 32例中共记录 5 4个靶点 ,成功靶点的PPI-TCL值明显小于不成功靶点 (12 .4± 5 .8msvs 32 .1± 18.6ms,P <0 .0 1)。PPI-TCL值≤ 2 0ms对靶点成功消融的敏感性和特异性分别为 84%、81%。结论 :本研究提示常规慢径消融成功部位作为房室结外的后部延伸组织参与组成AVNRT折返环或距其非常近。在可持续发作和诱发的AVNRT患者中 ,CSO部位起搏拖带顺向心房夺获时 ,靶点部位测出的PPI-TCL值≤ 2 0ms,可作为一种新的慢径路电生理定位消融方法

Correlation of Postpacing Interval at Target Site and the Result of Slow Pathway Ablation.

To investigate the relationship of postpacing interval at target site and the result of slow pathway ablation,34 patients with typical atrioventricular nodal reentrant tachycardia (AVNRT) were prospectively included in the study.Sustained tachycardia was reproducibly inducible in all patients.Anatomic and electrogram combined guided mapping of the slow pathway was started posteroseptally and continued to more midseptal sites if required.During ongoing tachycardia,overdrive pacing from high right atrium (HRA) and coronary sinus (CSO) were performed respectively,concealed entrainment developed.Irrespective of the postpacing interval(PPI) at the eligible ablation site,radiofrequency current was delivered at each site after exclusion of catheter dislocation.Results: Antidromic atrial capture of His bundle recorded area occurred during concealed entrainment from HRA overdrive pacing,while orthodromic atrial capture occurred during CSO overdrive pacing in 32 patients,antidromic atrial capture occurred in other 2 patients.54 target sites were recorded in 32 patients with orthodromic atrial capture.The differential value between PPI and (TCL) at the successful site was significantly less than at unsuccessful site(12.4±5.8 ms vs 32.1±18.6 ms P < 0.01 ),and the value of less than 20 ms identified successful target sites with 84% sensitivity and 81 % specificity.Conclusion:These results suggest that succesful ablation site is a part of or very close to AVNRT reentrant circuit as extranodal posterior extension tissue,the differential value between PPI and TCL of less than 20 ms may identify rational target site for slow pathway ablation in patients with sustained AVNRT reproducibly.[Chinese Journal of Cardiac Pacing and Electrophysiology,2000,14(3):151～155]