Tchou P, Lehmann M H, Jazayeri M, Akhtar M
Natalie and Norman Soref and Family Electrophysiology Laboratory, University of Wisconsin-Sinai Samaritan Medical Center, Milwaukee 53233.
Circulation. 1988 Apr;77(4):837-48. doi: 10.1161/01.cir.77.4.837.
Accessory pathways showing decremental properties and inserting into the right ventricle have been frequently described as "nodoventricular" or Mahaim pathways. However, conclusive evidence for a nodal origination of such pathways is lacking. The patient in this study had characteristics typical of such a pathway. Antegradely, the pathway showed decremental, nodelike conduction properties. With the aid of right bundle branch recordings, the pathway was demonstrated to insert directly into the right bundle branch. Atrioventricular reciprocating tachycardia could be readily initiated by atrial or ventricular pacing. The QRS morphology was normal during sinus rhythm and demonstrated a left bundle branch block pattern with normal axis during tachycardia. The reentrant circuit involved antegrade conduction over the accessory pathway and retrograde conduction via the bundle branches, His bundle, and the atrioventricular node. More significantly, late atrial stimuli delivered during tachycardia could preexcite the ventricle via the accessory pathway despite their inability to enter the atrioventricular node. Thus, the upper "turn around" of the reentrant circuit involved atrial tissue and the accessory pathway originated directly from the right atrium independent of the atrioventricular node. In view of these new findings and other recent observations during surgical resection of similar pathways, a reassessment of previous descriptions of "nodoventricular" fibers may be necessary. Many of these pathways may actually represent atriofascicular or atrioventricular connections with decremental properties.
表现出递减特性并插入右心室的旁路经常被描述为“结室”或Mahaim旁路。然而，缺乏关于此类旁路起源于结的确凿证据。本研究中的患者具有此类旁路的典型特征。顺行时，该旁路表现出递减的、类似结的传导特性。借助右束支记录，证实该旁路直接插入右束支。房室折返性心动过速可通过心房或心室起搏轻易诱发。窦性心律时QRS形态正常，心动过速时呈正常电轴的左束支阻滞图形。折返环包括通过旁路的顺行传导以及经束支、希氏束和房室结的逆行传导。更重要的是，心动过速期间发放的晚期心房刺激尽管无法进入房室结，但仍可通过旁路预激心室。因此，折返环的上部“折返”涉及心房组织，且旁路直接起源于右心房，独立于房室结。鉴于这些新发现以及近期在类似旁路手术切除过程中的其他观察结果，可能有必要重新评估之前对“结室”纤维的描述。其中许多旁路实际上可能代表具有递减特性的房束或房室连接。
