Mickleborough L L, Wilson G J, Harris L, Tashiro T, Parson I, Gray G
Division of Cardiovascular Surgery, Toronto General Hospital, Ontario, Canada.
J Thorac Cardiovasc Surg. 1989 Jan;97(1):135-46.
We have recently developed a transatrial balloon approach for intraoperative endocardial mapping of ventricular tachycardia, which can be performed in the intact ventricle. In selected patients, we have eliminated the arrhythmia by passing a series of electric currents through specific beads on the balloon array. The goal of this new technique, balloon electric shock ablation, is to create a homogenous scar in the subendocardial target area identified by mapping. Experimental data exist on the effects of catheter delivery of electric discharges to the myocardium, but no data are available on the effects of balloon electric shock ablation. We have performed balloon electric shock ablation in animals (nine cathodal shocks of 100 J given through a 4 cm2 electrode grid). Ventricular function was assessed at 6 weeks and compared with function after a simple ventriculotomy and with function in control animals having no operation. Gated nuclear ventriculograms were obtained during volume loading. Myocardial performance and diastolic pressure volume relationships were determined for the three groups. After balloon electric shock ablation or ventriculotomy, left atrial pressures were increased at similar end-diastolic volumes, which indicated decreased ventricular compliance. The trend reached statistical significance (compared with data from control animals) only in the group undergoing balloon electric shock ablation. Myocardial performance (stroke work index/end-diastolic volume relationship) was unchanged in the three groups. In the long-term balloon electric shock ablation preparation, an electrophysiologic study (including burst pacing) failed to induce ventricular arrhythmias. At 6 weeks, the lesion created by balloon electric shock ablation was a layer of homogenous mature scar with sharply defined borders. There was no evidence of additional injury to the surrounding myocardium or to the mitral valve apparatus. These studies show that delivery of a series of electric shocks through a 1 cm balloon grid of electrodes can create an area of homogeneous, electrically inert scar and that this procedure when performed in healthy dog hearts has no significant effect on the structure and function of the rest of the left ventricle.
我们最近开发了一种经心房球囊法，用于室性心动过速的术中心内膜标测，该方法可在完整的心室中进行。在选定的患者中，我们通过使一系列电流通过球囊阵列上的特定珠子消除了心律失常。这项新技术——球囊电击消融术的目标是在标测确定的心内膜下目标区域形成均匀的瘢痕。关于通过导管向心肌输送电脉冲的效果已有实验数据，但尚无关于球囊电击消融效果的数据。我们已在动物身上进行了球囊电击消融（通过4平方厘米的电极网格给予9次100焦耳的阴极电击）。在6周时评估心室功能，并与单纯心室切开术后的功能以及未手术的对照动物的功能进行比较。在容量负荷期间获取门控核心室造影。测定三组的心肌性能和舒张压-容积关系。球囊电击消融或心室切开术后，在相似的舒张末期容积时左心房压力升高，这表明心室顺应性降低。仅在接受球囊电击消融的组中，该趋势达到统计学意义（与对照动物的数据相比）。三组的心肌性能（每搏功指数/舒张末期容积关系）未改变。在长期的球囊电击消融准备中，电生理研究（包括猝发刺激）未能诱发室性心律失常。在6周时，球囊电击消融造成的病变是一层边界清晰的均匀成熟瘢痕。没有证据表明周围心肌或二尖瓣装置受到额外损伤。这些研究表明，通过1厘米球囊电极网格输送一系列电击可形成一个均匀的、电惰性的瘢痕区域，并且在健康犬心脏中进行此操作对左心室其余部分的结构和功能没有显著影响。
