磁导航遥控射频导管消融治疗房室结折返性心动过速的初步体会

Ablation of atrioventricular nodal reciprocating tachycardia using remote magnetic navigation system

目的探讨应用磁导航系统遥控射频导管消融治疗房室结折返性心动过速（AVNRT）的安全性和有效性。方法对37例腔内电生理证实为AVNRT的患者（女性29例），平均年龄（44±15）岁，应用NiobeⅡ磁导航系统控制HeliosⅡ磁性温控导管，实施慢径改良术，对于反复放电不出现交界性心律或出现“有效消融”仍能诱发出AVNRT者施行Koch三角基底部线性消融术。结果37例患者均实现即刻消融成功，其中14例实现慢径消融，余23例达到慢径改良，除1例患者出现一过性一度房室阻滞以外，余未出现相关并发症。平均消融次数（2．9±1．6）次，放电时间为（130±33）S，总消融时间为（120±32）min，总X线曝光时间为（5．3±2．7）min，术者X线曝光时间为（2．9±1．1）min。消融前后房室结前传文氏点、AH间期及HV间期等电生理参数无明显改变。后入组的19例患者总消融术时间、总X线曝光时间及磁导航遥控导管X线曝光时间较先人组的18例患者明显缩短，差异有统计学意义（P〈0．001），而术者X线曝光时间无明显改变，反映出应用磁导航系统进行AVNRT消融治疗仅需较短的学习曲线。结论应用磁导航系统可安全、有效地实施遥控射频导管消融治疗AVNRT，且学习曲线短，并明显减少术者的X线曝光时间。

Objective To evaluate the safety and feasibility of remote radiofrequency catheter ablation of atrioventricular nodal reciprocating tachycardia （AVNRT） using the magnetic navigation system （MNS）. Methods A total of 37 patients Ⅰ female 29, mean age （44 ± 15 ）years with documented AVNRT were enrolled in this study from March 2007 to June 2009. A 4 mm tip magnetic mapping and ablation catheter （ Helios Ⅱ , Stereotaxis, USA）, which was remotely controlled by the MNS （Niobe Ⅱ , Stereotaxis, USA）, was used for both mapping and ablation. Conventional slow pathway modification with focal ablation at the right posterior sep- rum was first performed in all patients. If it was failed, linear lesions at the base of Koch＇ s triangle was then done. Results After ablation, AVNRT was non-inducible in all 37 patients without any complication except one case experienced transient first degree AV block. Focal ablation was performed in 34 p.atients, and linear ablation strategy was used in the remaining three cases to achieve the end point. Among all the 37 patients, slow pathway ablation was achieved in 14, whereas slow pathway modification was reached in the remaining 23 cases. The mean procedural time,the RF deliveries,the duration of RF application were （ 120 ± 32） min, （2. 9 ± 1.6） times, （ 130 ± 33 ） s, respectively. The total fluoroscopy time and the physician X-ray exposure time were （ 5. 3± 2. 7）min and（2. 9± 1.1 ）min, respectively. There was no significant change of the AH interval, the HV interval,and the. atrioventricular nodal conduction refractory period after ablation. Compared with the first 18 patients, the mean procedural time, the total fluoroscopy time and the X-ray fluoroscopy time during magnetic navigation were significantly decreased in the later 19 patients （P 〈 0. 001 ）. It indicated that the learning curve of remote catheter ablation using the MNS is short. Conclusion Remote catheter ablation using the MNS to cure AVNRT is safe and effective with short learning curve and decreasing X-ray exposure time for interventional physicians.