Dubuc M, Roy D, Thibault B, Ducharme A, Tardif J C, Villemaire C, Leung T K, Talajic M
Department of Medicine, Montreal Heart Institute, Quebec, Canada.
Pacing Clin Electrophysiol. 1999 Oct;22(10):1488-98. doi: 10.1111/j.1540-8159.1999.tb00353.x.
While radiofrequency catheter ablation is very effective, it does not allow for prediction of success prior to full delivery of the energy. We investigated the use of cryoablation using a new catheter on the AV node to determine (1) if a successful site might be identified prior to the ablation itself, and (2) the parameters of cryoablation of the AV node using a new cryocatheter. In eight dogs, the cryoablation catheter was advanced to the AV node to produce transient high degree AV block by lowering the temperature to a minimum of -40 degrees C (ice mapping). Transient high degree AV node block was obtained in seven of eight animals at a mean temperature of -39.9 +/- 11.6 degrees C. No significant pathological modification was found in all animals but one and, in all cases, electrophysiological parameters of the AV node measured before, 20 minutes, 60 minutes, and up to 56 days after cryoapplication were not significantly different. In the 12 other dogs, after ice mapping, cryoablation of the AV node was attempted with a single freeze-thaw cycle in 6 dogs (group I) and a double freeze-thaw cycle in the other 6 dogs (group II). Chronic complete AV block was obtained in only one animal in group I compared to all animals in group II. Ablation of the AV node is effective with a double freeze-thaw cycle using a percutaneous catheter cryoablation system. Ice mapping of the area allows for identification of the targeted site.
虽然射频导管消融术非常有效，但在完全释放能量之前无法预测其成功率。我们研究了使用一种新型导管对房室结进行冷冻消融，以确定：（1）在消融本身之前是否可以识别出成功的部位；（2）使用新型冷冻导管对房室结进行冷冻消融的参数。在8只犬中，将冷冻消融导管推进至房室结，通过将温度降至最低-40℃（冰标测）来产生短暂的高度房室传导阻滞。8只动物中有7只在平均温度为-39.9±11.6℃时获得了短暂的高度房室结传导阻滞。除1只动物外，所有动物均未发现明显的病理改变，并且在所有情况下，冷冻应用前、20分钟、60分钟以及直至56天后测量的房室结电生理参数均无显著差异。在另外12只犬中，冰标测后，6只犬（I组）尝试采用单次冻融循环对房室结进行冷冻消融，另外6只犬（II组）采用双次冻融循环。I组仅1只动物获得了慢性完全性房室传导阻滞，而II组所有动物均获得了慢性完全性房室传导阻滞。使用经皮导管冷冻消融系统进行双次冻融循环消融房室结是有效的。对该区域进行冰标测可识别出目标部位。
