Fenelon G, Brugada P
Cardiovascular Research and Teaching Institute, Aalst, Belgium.
Pacing Clin Electrophysiol. 1998 Dec;21(12):2580-7. doi: 10.1111/j.1540-8159.1998.tb00034.x.
Anisotropic propagation may be involved in the development of areas of slow conduction in atrial flutter. We evaluated monophasic action potentials (MAPs) and simultaneous unipolar (0.2-400 Hz) and bipolar electrograms from multiple atrial sites of patients undergoing RF ablation of idiopathic atrial flutter. Nine patients (mean age 46 +/- 20 years) with typical atrial flutter (one with both types) were studied. Unipolar electrograms with triphasic complexes of small amplitude and with a slow, negative deviation of the baseline preceding the rS deflection indicated transversal conduction in relation to the orientation of cardiac fibers; smooth rS complexes longitudinal conduction; QS complexes onset of activation; and R complexes end of activation or collision. In all patients with typical atrial flutter, slow conduction occurred in the corridor between the inferior vena cava, the tricuspid annulus, and the coronary sinus. Transversal conduction was observed in this area, whereas the remaining sites showed longitudinal conduction. Anatomically guided RF ablation was successful in five patients. Transversal conduction was recorded in all successful sites. In the patient with atypical atrial flutter, slow conduction was noted in the high lateral right atrium, also exhibiting transversal conduction. Ablation at this area terminated the arrhythmia. All the areas of transversal conduction during flutter displayed longitudinal conduction after restoration of sinus rhythm. MAPs were normal in all patients during atrial flutter and sinus rhythm, even at the areas where transversal conduction was recorded. These findings suggest that anisotropic propagation is involved in the genesis of functionally determined areas of slow conduction during typical atrial flutter.
各向异性传导可能参与了心房扑动缓慢传导区域的形成。我们评估了接受特发性心房扑动射频消融术患者多个心房部位的单相动作电位（MAPs）以及同步单极（0.2 - 400 Hz）和双极电图。研究了9例（平均年龄46±20岁）典型心房扑动患者（其中1例两种类型均有）。小振幅三相复合波且在rS波之前基线有缓慢负向偏移的单极电图提示与心肌纤维方向相关的横向传导；光滑的rS复合波提示纵向传导；QS复合波提示激动开始；R复合波提示激动结束或碰撞。在所有典型心房扑动患者中，下腔静脉、三尖瓣环和冠状窦之间的通道出现缓慢传导。该区域观察到横向传导，而其余部位显示纵向传导。解剖学引导下的射频消融在5例患者中成功。所有成功部位均记录到横向传导。在非典型心房扑动患者中，右心房高位侧壁出现缓慢传导，也表现为横向传导。该区域消融终止了心律失常。心房扑动期间所有横向传导区域在恢复窦性心律后均显示纵向传导。在心房扑动和窦性心律期间，所有患者的MAPs均正常，即使在记录到横向传导的区域也是如此。这些发现表明，各向异性传导参与了典型心房扑动期间功能决定的缓慢传导区域形成。
