阈下刺激定位慢径消融靶点的临床应用研究

Clinical study of target sites of ablation of slow pathway guided by subthreshold stimulation

目的 :探讨利用阈下刺激 (STS)定位房室结折返性心动过速 (AVNRT)的慢径消融靶点的临床应用价值。方法 :选择AVNRT患者 6例 ,经常规电生理检查明确诊断后 ,将大头电极放在冠状窦口下缘与希氏束之间的中下区域进行标测 ,测定该点的起搏阈值后 ,诱发AVNRT ,然后发放STS终止AVNRT ,在终止位点处试消融 ,观察STS标测消融的有效性 ;在非终止位点处 ,结合局部心内电图判断是否进行试消融 ,如在非终止位点处试消融 ,观察STS标测的可靠性。同时观察STS标测定位的安全性。结果 :在 6例患者中 ,有 3例STS终止了持续性AVNRT ,且在终止位点处试消融并获得成功 ;有 5例共在 10个位点处发放了STS ,其中在 9个位点未终止心动过速 ,在这些非终止位点处试消融均未获得成功 ,非 1个位点出现了心房夺获。所有患者在STS标测过程中 ,未出现心房颤动、心动过速的加速或心室颤动等现象。结论 :STS终止AVNRT的位点是判断消融靶点的一个良好的电生理学指标。STS标测定位是安全、有效和可靠的一种方法 。

Objective:The present study investigate the clinical value of target sites of ablation of slow pathway guided by STS.Methods:Six patients of AVNRT were prospectively included in the study. Sustained tachycardia was reproducibly inducible in all patients in the course of procedure, and clear diagnoses by conventional methods of electrophysiologic examination. Ablation electrode tip was introduced and placed within middle-low area between lower rim of coronary sinus ostium and His bundle. After pacing threshold of located site was measured,sustained tachycardia was terminated by STS, the termination sites were accepted as target sites for radiofrequency current delivery, positive predictive value(sensibitity) was observed. If sustained tachycardia was not terminated by STS, endocardiac electrograms determined whether the mapping sites were eligible for ablation or not, if the site was accepted as target sites for ablation, negative predictive value(specificity) was observed. secuity of target sites of ablation guided by STS were observed in all patients.Results:Sustained AVNRT was terminated by UST in 3 among 6 patients, 3 termination sites were performed ablation, which were successful ablation sites, the sensitivity of AVNRT termination by UST at slow pathway sites was very high(3/3). There were 9 sites that Sustained AVNRT cannot be terminated by UST in 5 among 6 patients, 9 no termination sites were performed ablation, which were not successful ablation sites, the specificity of USTS terminated sites being accepted as target sites for ablation was very high also(9/9). Atrial fibrillation, accelerated tachycardia or ventricular fibrillation were not found in the course of procedure among all 6 patients.Conclusion:Termination sites of reentrant tachycardia by STS is a good mapping index of electrophysiology.STS mapping is a safe,effective and reliable method,and further investigations with this method are very valuable.