左侧房室旁道消融过程中伴发的二尖瓣峡部阻滞

Mitral isthmus conduction block during ablation for left accessory pathway

目的评估房室旁道消融过程中二尖瓣峡部阻滞的发生率,并探讨其电生理特性。方法以2003年7月至2011年1月本中心接受射频消融治疗的左侧房室旁道患者为研究对象,分析旁道分布特点、手术方法、手术时间、成功率及术中峡部阻滞的影响因素,探讨不同类型峡部阻滞的电生理特性。结果在402例患者中共有8例出现峡部阻滞现象(2.0%)。峡部阻滞多数出现于左侧游离壁旁道消融过程(87.5%);多于房间隔穿刺法消融术中出现(87.5%);其手术时间更长[(213.6±36.5)min vs(76.4±23.5)min,P<0.05],更可能是再次接受射频消融治疗患者(62.5%vs 1.5%,P<0.05)。术中峡部阻滞时可出现冠状窦电极VA间期延长或心房激动顺序改变,但局部His束电极上VA间期及心动过速周长不变;旁道附近的VA间期不变。结论左侧旁道消融过程中可伴发二尖瓣峡部阻滞,并有其相应电生理特性。

Objective To investigate the incidence of mitral isthmus conduction block during left accessory pathway ablation and the accompanying electrophysiological properties. Methods From July 2003 to Jan 2011, 402 left accessory pathway cohorts were accepted radiofrequency ablation and were evaluated of accessory pathway distribution characteristics, operational approach, operative time, success rate and electrophysiological properties of different mitral isthmus conduction block. Results In total of 402 patients, mitral isthmus conduction block was observed in 11 cases （2.0%）. This was evidenced by a sudden change in retrograde left atrial activation sequence despite persistent and unaffected pathway conduction. Most of the conduction block occurred in left free wall accessory pathway following RF delivery（ 87.5% ）, with transseptal approach （ 87.5 % ）, longer procedure time [ （ 213.6 ±36.5 ） min vs （76.4±23.5） min, P〈0.05 ], and more likely to be re-treated patients（62.5% vs 1.5% , P〈0. 05 ）. In patients with isthmus conduction block,while local VA interval prolongation was observed with or without reversal of retrograde CS atrial activation sequence, tachycardia cycle length and His-VA interval remained constant in all patients. Conclusion Mitral isthmus conduction block with its own electrophysiological characteristics is an unusual phenomenon during left accessory pathway ablation.