实验性心肌梗塞后室性心动过速的低温标测与冷凝消融

Hypothermal Mapping and Cryoablation of Ventricular Tachycardia in Dogs After Myocardial Infarction

对１２条犬进行了冷凝后病理学、血液动力学及动态心电图观察，另１０条犬建立心肌梗塞（简称心梗）和室性心动过速（ＶＴ）模型，并进行低温标测和冷凝消融。结果显示：①心内膜冷凝损伤灶的长、短径和深度大于心外膜冷凝（３６．６０±１１．０６ｍｍｖｓ２２．８０±３．７０ｍｍ、２９．３０±１０．９７ｍｍｖｓ１９．６０±３．１２ｍｍ、８．１４±２．４１ｍｍｖｓ５．１６±２．０３ｍｍ，Ｐ均＜０．０５），冷凝损伤灶与其周围正常心肌分界清楚。②１０条心梗犬采用电刺激或乌头碱诱发出２０次持续性ＶＴ，低温标测和冷凝消融均成功。③心外膜冷凝６条犬行动态心电图监测，均于术后３日内出现室性心律失常，７日后动态心电图检查基本恢复正常。依据上述较高的成功率、短暂致心律失常作用及无心功能障碍等可以认为低温标测和冷凝消融是治疗难治性室性心动过速的一种安全可行的方法。

Cryoablation was performed both on epicardium of 7 dogs and on endocardium of 5 dogs.Another 10 dogs were used to establish models of myocardial infarction and ventricular tachycardias (VTs),and then underwent hypothermal mapping and cryoablation.A series of changes in pathology,hemodynamics,and electrophysiology of the all dogs were observed in cryoablation.Results:(1)The size of the cryolesions on endocardial cryoablation was longer,wider,and deeper than those on epicardial cryoablation (36 60±11 06 mm vs 22.80±3.70 mm,29.30±10.97 mm vs 19.60±3.12 mm,8.14±2.41 mm vs 5.16±2.03 mm, P <0 05,respectively).The cryolesions were clearly demarcated from around normal myocardium.(2)Twenty sustained VTs were induced with electric pulse stimulation or injection of aconitine.The twenty VTs were localized by hypothermal mapping and cryoablated successfully through epicardial or endocardial approach.(3)Holter revealed ventricular arrhythmias in all the dogs after cryoablation,but all the arrhythmias disappeared automatically in 7 days after cryoablation.Conclusion:the high success rate,short duration of arrhythmogenic effect and no serious heart dysfunction during hypothermal mapping and cryoablation suggest that the hypothermal mapping and cryoablation would be a safe,available and feasible method for the treatment of refractory ventricular tachycardias.