Cosío Francisco G
Chief Cardiology Service, Hospital Universitario de Getafe, Madrid, Spain.
Card Electrophysiol Rev. 2002 Dec;6(4):356-64. doi: 10.1023/a:1021119905261.
Typical atrial flutter has long been considered a reentrant arrhythmia, but it is only recently that the full structure of the right atrial circuit was understood, leading to de devise of ablation techniques. Recognition of the role of functional block, based on anisotropic conduction was crucial to understanding of the flutter circuit. Anisotropy at the terminal crest creates a line of block that, with the orifices of superior and inferior vena cava, constitutes the posterior boundary of the flutter circuit. The anterior boundary is the tricuspid ring, and the circuit is a ring of myocardium made by the septal and anterior right atrial walls, linked on top by the right atrial roof and inferiorly by the inferior vena cava-tricuspid ring isthmus. This isthmus, a relatively narrow part of the circuit, has become the established target for typical flutter ablation. Complete, bidirectional isthmus block is the final goal of flutter ablation. This has to be assessed, after flutter interruption, by pacing both sides of the ablation line while recording electrogram sequences from the opposite right atrial wall and the isthmus itself. Success is great in terms of prevention of flutter recurrence, however a 30% incidence of atrial fibrillation during follow-up casts a large shadow on long-term prognosis. Understanding of the myocardial abnormalities underlying atrial flutter and fibrillation will be necessary to improve this long-term outlook.
典型心房扑动长期以来一直被认为是一种折返性心律失常，但直到最近才了解到右心房折返环的完整结构，从而促使了消融技术的设计。认识到基于各向异性传导的功能性阻滞的作用对于理解扑动环至关重要。终末嵴处的各向异性形成一条阻滞线，该阻滞线与上、下腔静脉口一起构成扑动环的后边界。前边界是三尖瓣环，折返环是由房间隔和右心房前壁构成的心肌环，在上方由右心房顶部相连，在下方由下腔静脉-三尖瓣环峡部相连。这个峡部是折返环相对狭窄的部分，已成为典型心房扑动消融的既定靶点。完全双向峡部阻滞是心房扑动消融的最终目标。在扑动终止后，必须通过在消融线两侧起搏，同时记录右心房对侧壁和峡部本身的电图序列来评估是否达到该目标。就预防扑动复发而言成功率很高，然而随访期间30%的心房颤动发生率给长期预后蒙上了巨大阴影。要改善这种长期预后，有必要了解心房扑动和心房颤动背后的心肌异常情况。
