多型房室结折返性心动过速的机制和射频导管消融

The electrophysioiogic mechanism and radiofrequency catheter ablation in patients with multiple atrio- ventricular nodal reentrant tachycardia

目的分析多型房室结折返性心动过速（AVNRT）并存的电生理机制和射频导管消融结果。方法18例经电生理检查后行射频导管消融的多型AVNRT患者。慢快型和慢慢型AVNRT的消融方法为首选消融前传慢径（房室结右侧后延伸），快慢型AVNRT的消融方法为消融最早慢径逆传心房激动部位。消融成功的标准为消除1：1前传慢径，消除快慢型AVNRT的逆传慢径，不能诱发任何类型AVNRT。结果11例在消融前的电生理检查中诱发出2种类型AVNRT，均在三尖瓣环与冠状静脉窦口之间（房室结右侧后延伸）成功消融。7例在电生理检查中诱发出1种类型，消融此型后又诱发出另外1种类型，其中4例在房室结右侧后延伸进一步消融成功，另3例均经左侧后延伸进一步消融成功。消融术后随访6个月至8年，18例均无复发。结论对于大多数多型AVNRT，房室结右侧后延伸可能为其折返环的主要基质，消融可成功治愈多型AVNRT。在少部分多型AVNRT中，左侧后延伸与右侧后延伸可能分别作为不Ⅻ类型AVNRT折返环的主要基质，需要分别消融才能成功治愈。

Objective The mechanism and catheter ablation of multiple atrioventricular nodal reen- trant tachycardias（AVNRT） have not been well investigated. The purpose of this study was to explore the elec- trophysiologic mechanism and evaluate the efficacy of catheter ablation in patients with multiple AVN- RT. Methods Eighteen patients with muhiple AVNRT （ ≥ 2 forms） underwent electrophysiological study and catheter ablation were performed. For ablation of slow/fast and slow/slow AVNRT, the antegrade slow pathway （right posterior extension of the AV node）was initially targeted. For ablation of fast/slow AVNRT, radiofre- quency ablation was initially directed at the site with earliest retrograde atrial activation during slow pathway conduction. The end points of ablation were elimination of 1 ： 1 antegrade slow pathway conduction and retro- grade slow pathway conduction participated in AVNRT, and especially uninducibility of any form of AVNRT. Results The incidence of multiple forms of AVNRT was 1.8% （18/1000）. Among the 18 patients,2 forms of AVNRT were induced before ablation in I l patients, and the second form of AVNRT could only be induced after ablation of the first form of AVNRT in the other 7 patients. In the 11 patients with induced multiple forms of AVNRT before ablation, ablation between the tricuspid annulus （ TA ）and the coronary sinus （CS） ostium （ right posterior extension） successfully eliminated multiple forms of AVNRT in all the 11 patients. In the other 7 patients, the second form of AVNRT was eliminated after further extensive ablation between TA and CS ostium in 4 patients, and the left posterior extension（ within the proximal CS and at the atrial aspect of the proximal mitral annulus） need to be ablated to eliminate the second form of AVNRT in the other 3 patients. There was no recurrence during 6 months to 8 years of follow-up. Conclusion In most patients with multiple forms of AVN- RT,the main substrate might be the right posterior extension of the AV node using antegrade and retrograde conduction separately during different forms of AVNRT. Therefore targeting the right posterior extension would eliminate multiple forms of AVNRT in most patients. However, both the right and left posterior extensions would be ablated to eliminate multiple forms of AVNRT in few patients.