Liem L B, Pomeranz M, Riseling K, Anderson S, Berry G J
Stanford University, California, USA.
Pacing Clin Electrophysiol. 2000 Jan;23(1):40-6. doi: 10.1111/j.1540-8159.2000.tb00648.x.
The purpose of this study is to describe the characteristics of lesions created using radiofrequency (RF) energy delivered through a saline/foam electrode that is designed to simplify ablation of the isthmus between the tricuspid annulus (TA) and the inferior vena cava (IVC). We compared the changes in the electrophysiological parameters produced by the ablation to histological findings. In search of a more practical and effective atrial flutter ablation method, various energy modifications and catheter designs have been tested. It was shown that the efficiency of RF ablation could be improved using an endocardial cooled catheter; resulting in increased lesion size. Thus, we postulate that a similar advantage of the cooled catheter system would allow efficient RF delivery through specially designed long foam electrodes, therefore improving the practicality of TA-IVC isthmus ablation for atrial flutter. The study was performed in two acute and five subacute sheep under general anesthesia and with adequate heparinization. We used a linear ablation catheter system equipped with two 2-cm saline bipole electrode pockets with 1.5-mm separation, each consisting of two 8-mm electrodes with 1-mm spacing, allowing for bipolar pacing and recording. This saline/foam electrode pair were positioned on a support loop. RF energy was applied to the saline electrodes at 50 watts for 90 seconds with a saline flow rate of 0.4 mL/s. Bipolar atrial signal amplitude and pacing thresholds were measured before and after ablation. If necessary, the catheter was pulled back and additional ablation was applied to any viable tissue. Transisthmus ablations were created with a single catheter positioning in five sheep using both saline electrodes in four and one electrode in the other. Pullback and additional ablation to one saline electrode was required in two sheep; in one after RF was delivered to only one electrode. After ablation, atrial signal amplitude was reduced by an average of 76% (range 51%-92%) and its pacing threshold was increased by an average of 617% (range 150%-400%). Transmural lesions were found in all sheep, measuring 8-20 mm in length, 4-10 mm in width, and 1.5-2.0 mm in depth. No charring, coagulum, or remote structural damage was found in any preparation. Continuous transmural TA-IVC isthmus lesions could be produced with stationary RF linear ablation using a saline/foam electrode catheter system. This system allowed for assessment of electrophysiological parameters that correlated with complete necrosis.
本研究的目的是描述使用通过盐水/泡沫电极输送的射频（RF）能量所产生的损伤特征，该电极旨在简化三尖瓣环（TA）与下腔静脉（IVC）之间峡部的消融。我们将消融产生的电生理参数变化与组织学结果进行了比较。为了寻找更实用、有效的心房扑动消融方法，已经测试了各种能量改进和导管设计。结果表明，使用心内膜冷却导管可提高射频消融的效率，从而增加损伤大小。因此，我们推测冷却导管系统的类似优势将允许通过专门设计的长泡沫电极有效输送射频能量，从而提高TA-IVC峡部心房扑动消融的实用性。该研究在全身麻醉并充分肝素化的2只急性和5只亚急性绵羊身上进行。我们使用了一种线性消融导管系统，该系统配备了两个2厘米长的盐水双极电极袋，间距为1.5毫米，每个电极袋由两个间距为1毫米的8毫米电极组成，可进行双极起搏和记录。这对盐水/泡沫电极位于一个支撑环上。以50瓦的功率向盐水电极施加射频能量90秒，盐水流速为0.4毫升/秒。在消融前后测量双极心房信号幅度和起搏阈值。如有必要，将导管回撤，并对任何存活组织进行额外消融。在5只绵羊中，使用单个导管定位，4只绵羊使用两个盐水电极，另1只绵羊使用一个电极进行峡部跨壁消融。2只绵羊需要对一个盐水电极进行回撤和额外消融；其中1只在仅向一个电极输送射频能量后进行。消融后，心房信号幅度平均降低76%（范围为51%-92%），起搏阈值平均增加617%（范围为150%-400%）。在所有绵羊中均发现了透壁损伤，长度为8-20毫米，宽度为4-10毫米，深度为1.5-2.0毫米。在任何标本中均未发现炭化、凝血块或远处结构损伤。使用盐水/泡沫电极导管系统进行固定射频线性消融可产生连续的透壁TA-IVC峡部损伤。该系统允许评估与完全坏死相关的电生理参数。
