Holman W L, Ikeshita M, Lease J G, Smith P K, Lofland G K, Cox J L
J Thorac Cardiovasc Surg. 1986 Jun;91(6):826-34.
Paroxysmal supraventricular tachycardia resulting from atrioventricular nodal reentry is a common arrhythmia that usually responds to medical therapy. When atrioventricular nodal reentry tachycardia is refractory to medical therapy, cryoablation or endocardial catheter ablation of the His bundle has been employed to protect the ventricles from the tachycardia. However, these techniques necessitate implantation of a permanent ventricular pacemaker. A cryosurgical procedure that ablates the anatomic-electrophysiologic substrate for atrioventricular nodal reentry tachycardia while preserving antegrade atrioventricular conduction has been described. The purpose of the present study was to determine the effects of this procedure on retrograde atrioventricular conduction and on the ventricular echo phenomenon in particular. Thirty adult mongrel dogs underwent either the cryosurgical procedure (n = 20) or a sham operation (n = 10). The animals were studied either immediately postoperatively (acute cryosurgery group and control group, n = 10 for each group) or 14 weeks postoperatively (chronic cryosurgery group, n = 10). Decremental ventricular pacing and programmed premature ventricular pacing protocols were used to determine the retrograde atrioventricular nodal conduction time, Wenckebach point, atrioventricular nodal refractory periods, and ventricular echo reflection time. No electrophysiologic alterations were noted in the sham-operated group. In the acute cryosurgery group, the retrograde Wenckebach point, atrioventricular nodal conduction time, functional refractory period of the atrioventricular node, effective refractory period of the atrioventricular node, and ventricular echo reflection time were all significantly prolonged. In the chronic cryosurgery group, no significant change in ventriculoatrial conduction was noted, but the ventricular echo phenomenon was eliminated in all but one animal. These data further document that this cryosurgical procedure is capable of ablating the anatomic-electrophysiologic substrate necessary for atrioventricular nodal reentry tachycardia while preserving atrioventricular conduction.
房室结折返引起的阵发性室上性心动过速是一种常见的心律失常，通常对药物治疗有反应。当房室结折返性心动过速对药物治疗无效时，已采用冷冻消融或希氏束心内膜导管消融来保护心室免受心动过速影响。然而，这些技术需要植入永久性心室起搏器。已经描述了一种冷冻手术程序，该程序在保留房室前向传导的同时，消融房室结折返性心动过速的解剖 - 电生理基质。本研究的目的是确定该手术对逆行房室传导，特别是对心室回声现象的影响。30只成年杂种犬接受了冷冻手术（n = 20）或假手术（n = 10）。对动物在术后立即（急性冷冻手术组和对照组，每组n = 10）或术后14周（慢性冷冻手术组，n = 10）进行研究。采用递减心室起搏和程序性室性早搏起搏方案来确定逆行房室结传导时间、文氏点、房室结不应期和心室回声反射时间。假手术组未观察到电生理改变。在急性冷冻手术组中，逆行文氏点、房室结传导时间、房室结功能不应期、房室结有效不应期和心室回声反射时间均显著延长。在慢性冷冻手术组中，未观察到室房传导有显著变化，但除一只动物外，所有动物的心室回声现象均消失。这些数据进一步证明，这种冷冻手术程序能够在保留房室传导的同时，消融房室结折返性心动过速所需的解剖 - 电生理基质。
