Littmann L, Svenson R H
Circulation. 1982 Jun;65(6):1269-75. doi: 10.1161/01.cir.65.6.1269.
Alternating WEnckebach periodicity is generally believed to reflect bilevel block due to horizontal electrophysiologic dissociation in the conducting tissues. We describe a case of atrial pacing-induced atrioventricular nodal alternating Wenckebach periodicity with concealed reentry in a longitudinally dissociated AV conduction system. Three observations support this unique mechanism: Concealed reentry occurred during the course of alternating Wenckebach periodicity; it could be invoked to explain the peculiar conduction patterns in this patient; and alternative mechanisms did not explain the alternating Wenckebach periods. Our findings also indicate that long conduction times during 2:1 block can be due to concealed reentry rather than concealed antegrade conduction, and participation in the echo process of a retrograde pathway with electrophysiologic characteristics of an atrioventricular nodal bypass tract does not exclude manifest and concealed reentry at a subatrial level.
交替性文氏周期一般被认为是由于传导组织中的水平电生理分离导致的双水平阻滞。我们描述了一例心房起搏诱发房室结交替性文氏周期并伴有纵向分离的房室传导系统隐匿性折返的病例。三项观察结果支持这一独特机制：隐匿性折返发生在交替性文氏周期过程中；它可以用来解释该患者的特殊传导模式；而其他机制无法解释交替性文氏周期。我们的研究结果还表明，2:1阻滞时的长传导时间可能是由于隐匿性折返而非隐匿性前向传导，并且具有房室结旁路电生理特征的逆行途径参与折返过程并不排除心房下水平的显性和隐匿性折返。
