Friedman P A, Luria D, Fenton A M, Munger T M, Jahangir A, Shen W K, Rea R F, Stanton M S, Hammill S C, Packer D L
Division of Cardiovascular and Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Circulation. 2000 Apr 4;101(13):1568-77. doi: 10.1161/01.cir.101.13.1568.
Previous studies of atrial flutter have found linear block at the crista terminalis; this was thought to predispose the patient to the arrhythmia. More recent observations, however, have demonstrated crista conduction. We sought to characterize the posterior boundary of atrial flutter.
Patients with counterclockwise flutter (n=20), clockwise flutter (n=3), or both (n=5) were studied using two 20-pole catheters. Biplane fluoroscopy determined catheter positions. During counterclockwise flutter, craniocaudal activation occurred along the entire lateral and posterior right atrial walls. Septal activation proceeded caudocranially. In all patients, a line of block was seen in the posteromedial (sinus venosa) right atrium; this was manifested by the presence of double potentials where the upward and downward activations collided. Anatomic location was confirmed by intracardiac echocardiography in 9 patients. In patients with clockwise flutter, the line of block and double potentials were seen in the same location during counterclockwise flutter, but the activation sequence around the line of block was reversed. Pacing near the site of double potentials during sinus rhythm excluded a fixed line of block, and premature atrial complexes demonstrated functional block with manifest double potentials. In 2 patients, posterior ectopy organized to subsequently initiate isthmus-dependent atrial flutter.
(1) A functional line of block is seen at the posteromedial (sinus venosa region) right atrium during counterclockwise and clockwise atrial flutter. (2) All lateral wall right atrial activation can be uniform during flutter, without linear block or double potentials in the region of the crista terminalis. (3) Activation at the site of posteromedial right atrial functional block can organize to subsequently initiate isthmus-dependent atrial flutter.
既往关于心房扑动的研究发现界嵴处存在线性阻滞；曾认为这会使患者易患心律失常。然而，最近的观察显示界嵴存在传导。我们试图明确心房扑动的后界。
使用两根20极导管对逆时针房扑患者（n = 20）、顺时针房扑患者（n = 3）或两者皆有的患者（n = 5）进行研究。双平面荧光透视确定导管位置。在逆时针房扑期间，头尾向激动沿整个右心房外侧和后壁发生。间隔激动从尾头向进行。在所有患者中，右心房后内侧（腔静脉窦）可见一条阻滞线；表现为向上和向下激动碰撞处出现双电位。9例患者通过心内超声心动图证实了解剖位置。在顺时针房扑患者中，逆时针房扑期间阻滞线和双电位出现在相同位置，但阻滞线周围的激动顺序相反。窦性心律时在双电位部位附近起搏排除了固定的阻滞线，房性早搏显示存在具有明显双电位的功能性阻滞。在2例患者中，后部异位激动组织起来随后引发了峡部依赖性心房扑动。
（1）在逆时针和顺时针心房扑动期间，右心房后内侧（腔静脉窦区域）可见一条功能性阻滞线。（2）房扑期间右心房所有侧壁的激动可以是均匀的，界嵴区域无线性阻滞或双电位。（3）右心房后内侧功能性阻滞部位的激动可组织起来随后引发峡部依赖性心房扑动。
