Milla Federico, Skubas Nikolaos, Briggs William M, Girardi Leonard N, Lee Leonard Y, Ko Wilson, Tortolani Anthony J, Krieger Karl H, Isom O Wayne, Mack Charles A
New York Presbyterian Hospital-Weill Cornell Medical Center, Department of Cardiothoracic Surgery, New York, NY, USA.
J Thorac Cardiovasc Surg. 2006 Feb;131(2):403-11. doi: 10.1016/j.jtcvs.2005.10.048. Epub 2006 Jan 18.
Epicardial, beating heart cryoablation for the treatment of atrial fibrillation may be limited by heat from intracardiac blood flow. We therefore evaluated the ability to create cryolesions using an argon-based cryoclamp device, which temporarily occludes blood flow and facilitates transmurality.
Six mongrel dogs underwent sternotomy. A clamp employing a 10-cm argon-based linear cryoablation device was used epicardially to isolate the pulmonary veins and left atrial appendage. After clamping of lesions, the probe was removed from the cryoclamp device, and the remaining linear lesions, analogous to the Cox maze III, were performed. Pulmonary vein stenosis was evaluated with the use of magnetic resonance imaging. Left atrial function and pulmonary venous flow velocities were assessed with transesophageal echocardiography. Transmurality was confirmed both electrically and histologically. Animals were then put to death at 30 days.
All acute and chronic cryoclamp lesions produced conduction block. There was no change in right (RPV) or left pulmonary vein (LPV) diameter on the basis of magnetic resonance imaging at baseline and at planned death (RPV-1, 19.6 +/- 2.9 mm vs 16.9 +/- 2.8 mm, P = .22; RPV-2, 13.2 +/- 2.0 mm vs 11.8 +/- 1.6 mm, P = .22; and LPV, 12.2 +/- 2.4 mm vs 11.2 +/- 1.9 mm, P = .30). Left atrial function and pulmonary venous flow velocities were unchanged. Tissue sections determined transmurality in 93% of cryoclamp lesions and 84% of linear ablations performed with the 10-cm malleable probe.
Epicardial application of this cryoclamp device on the beating heart produced transmural lesions, which persisted 30 days. Linear epicardial cryoablation was not as effective as the cryoclamp device at producing consistent transmural lesions. This novel, versatile device may be useful in treating patients with atrial fibrillation on the beating heart without cardiopulmonary bypass.
心外膜下跳动心脏冷冻消融治疗心房颤动可能会受到心腔内血流产生的热量的限制。因此，我们评估了使用基于氩气的冷冻夹装置制造冷冻损伤的能力，该装置可暂时阻断血流并促进透壁性。
对6只杂种犬进行胸骨切开术。使用一个采用10厘米基于氩气的线性冷冻消融装置的夹子在心外膜下隔离肺静脉和左心耳。在夹住损伤部位后，将探头从冷冻夹装置中取出，然后进行类似于Cox迷宫III的其余线性损伤操作。使用磁共振成像评估肺静脉狭窄情况。经食管超声心动图评估左心房功能和肺静脉血流速度。通过电生理和组织学方法确认透壁性。然后在30天时对动物实施安乐死。
所有急性和慢性冷冻夹损伤均产生传导阻滞。根据磁共振成像，在基线和计划处死时，右肺静脉（RPV）或左肺静脉（LPV）直径均无变化（RPV-1，19.6±2.9毫米对16.9±2.8毫米，P = 0.22；RPV-2，13.2±2.0毫米对11.8±1.6毫米，P = 0.22；LPV，12.2±2.4毫米对11.2±1.9毫米，P = 0.30）。左心房功能和肺静脉血流速度未改变。组织切片显示，93%的冷冻夹损伤和84%使用10厘米可弯曲探头进行的线性消融实现了透壁性。
在跳动心脏上心外膜应用这种冷冻夹装置产生了持续30天的透壁损伤。心外膜线性冷冻消融在产生一致的透壁损伤方面不如冷冻夹装置有效。这种新型、多功能装置可能有助于在不进行体外循环的情况下治疗跳动心脏上的心房颤动患者。
