REENTRANT EXCITATION AROUND A FIXED OBSTACLE IN UNIFORM ANISOTROPIC VENTRICULAR MYOCARDIUM
REENTRANT EXCITATION AROUND A FIXED OBSTACLE IN UNIFORM ANISOTROPIC VENTRICULAR MYOCARDIUM
复制标题
DOI：
10.1161/01.cir.84.3.1296
复制
发表时间：
1991-09-01
期刊：
影响因子：
37.8
通讯作者：
ALLESSIE, MA
中科院分区：
文献类型：
--
作者：
BRUGADA, J;BOERSMA, L;ALLESSIE, MA
背景。本研究的目的是探讨组织各向异性和难愈性离散性在重入性室性心动过速（VT）发生中的作用。方法与结果。采用心内膜冷冻技术在兰根多夫灌注兔心脏中制备了均匀各向异性心室心外膜灌注环。采用248通道高分辨率成像分析左心室心外膜激活。17个实验共272个点（每个实验环周围16个不同点）诱导1 ~ 3次早搏。可在272个测试点中的43个点启动重入式VT。VT周期长度稳定，范围为128 ~ 198 msec（平均161±19 msec）。传导速度与循环激活波与心外膜纤维取向夹角的相关性表明，在垂直于纤维轴的环段，平均传导速度为25 +/- 5 cm/sec，而平行于纤维取向的环段平均传导速度为60 +/- 7 cm/sec。对单向传导阻滞部位的分析表明，43例中有41例发生在脉冲平行于纤维方向传播时。在单向阻滞线两侧的不应期测量表明，43例中只有12例在脉冲传播到不应期较长（超过10毫秒）的区域时发生阻滞。在均匀各向异性心室心肌中，由于早搏降低去极化波的刺激作用，导致平行于纤维取向的优先传导阻滞，导致重入性室速启动。
Background. The purpose of this study was to investigate the role of tissue anisotropy and dispersion of refractoriness on initiation of reentrant ventricular tachycardia (VT).Methods and Results. A ring of perfused uniform anisotropic ventricular epicardium in Langendorff-perfused rabbit hearts was created by an endocardial freezing technique. High-resolution mapping (248 channels) was used to analyze epicardial activation of the left ventricle. One to three premature beats were induced at a total of 272 points in 17 experiments (16 different points around the ring in each experiment). Reentrant VT could be initiated at 43 of the 272 points tested. The cycle length of VT was stable and ranged from 128 to 198 msec (mean, 161 +/- 19 msec). Correlation between conduction velocity and the angle between the circulating activation wave and epicardial fiber orientation showed that in segments of the ring where conduction was perpendicular to the fiber axis, mean conduction velocity was 25 +/- 5 cm/sec compared with 60 +/- 7 cm/sec when conduction was parallel to the fiber orientation. Analysis of the site of unidirectional conduction block showed that in 41 of 43 cases, block occurred while the impulse was propagating parallel to the fiber orientation. Measurement of the refractory periods at either side of the line of unidirectional block showed that only in 12 of 43 cases did block occur while the impulse was propagating into an area with a longer (more than 10 msec) refractory period.Conclusions. In uniform anisotropic ventricular myocardium, reentrant VT is initiated because lowering the stimulating efficacy of the depolarization wave by premature beats leads to preferential conduction block parallel to the fiber orientation.