Anisotropic Reentry in a Perfused 2-Dimensional Layer of Rabbit Ventricular Myocardium
Anisotropic Reentry in a Perfused 2-Dimensional Layer of Rabbit Ventricular Myocardium
复制标题
兔心室心肌灌注二维层的各向异性折返
作者：
M. Schalij;L. Boersma;Maya Huijberts;M. Allessie
背景各向同性造成电传播的不均匀性，可能导致单向传导阻滞和再入。我们描述了各向异性心室心肌二维层的重入性心动过速的特征。方法与结果兔左心室壁内层冷冻制备langendorff灌注心外膜膜（1.0±0.4 mm, n=35）。心外膜激活图是利用不同的高分辨率测绘阵列连接到一个测绘系统来构建的。在5个实验中，记录单相动作电位。在完整的左心室，除室性心动过速外，未引起其他心律失常。冷冻后，程序性电刺激或快速起搏可诱导持续VT（周期长度130±11 ms）。室性心动过速是由平行于心外膜纤维方向的功能阻滞线周围再入引起的。动作电位记录表明，在阻滞中心线两侧传播的去极化波产生的电紧张电流使阻滞中心线保持耐火。在块体线的支点处，转弯波的明显曲率和负载的突然变化在重入路径中产生了30 ms的可激隙。结论均匀各向异性心肌可沿功能z型阻滞线再入。电紧张电流使电路的核心保持耐火。明显的波前曲率和支点处突然的载荷变化导致局部传导延迟并产生小的可激隙。
BackgroundAnisotropy creates nonuniformity in electrical propagation and may contribute to the occurrence of unidirectional conduction block and reentry. We describe the characteristics of reentrant tachycardia in a 2D layer of anisotropic ventricular myocardium. Methods and ResultsA Langendorff-perfused epicardial sheet (1.0±0.4 mm, n=35) was created by freezing the intramural layers of the rabbit left ventricle. Epicardial activation maps were constructed by use of different high-resolution mapping arrays connected to a mapping system. In 5 experiments, monophasic action potentials were recorded. In the intact left ventricle, no arrhythmias except VF could be induced. After freezing, programmed electrical stimulation or rapid pacing led to the induction of sustained VT (cycle length 130±11 ms). VT was caused by reentry around a functional line of block oriented parallel to the epicardial fiber direction. Action potential recordings demonstrated that the central line of block was kept refractory by electrotonic currents generated by the depolarization waves propagating at either side of the line of block. At the pivot points of the line of block, the pronounced curvature of the turning wave and abrupt loading changes created an excitable gap of 30 ms in the reentrant pathway. ConclusionsIn uniform anisotropic myocardium, reentry around a functional Z-shaped line of block may occur. The core of the circuit is kept refractory by electrotonic currents. The pronounced wave-front curvature and abrupt loading changes at the pivot points cause local conduction delay and create a small excitable gap.
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影响因子：
37.8
作者：
NIWANO, S;ORTIZ, J;WALDO, AL
通讯作者：
WALDO, AL
影响因子：
20.1
作者：
PERTSOV, AM;DAVIDENKO, JM;JALIFE, J
通讯作者：
JALIFE, J
引起持续性室性心动过速的各向异性折返回路中时间和空间可兴奋间隙的特征。
影响因子：
20.1
作者：
Peters,NS;Coromilas,J;Hanna,MS;Josephson,ME;Costeas,C;Wit,AL
通讯作者：
Wit,AL
影响因子：
37.8
作者：
N. Peters;J. Coromilas;N. Severs;A. L. Wit
通讯作者：
N. Peters;J. Coromilas;N. Severs;A. L. Wit
离体犬右心房功能折返自发终止的机制。
影响因子：
37.8
作者：
Ikeda,T;Uchida,T;Hough,D;Lee,JJ;Fishbein,MC;Mandel,WJ;Chen,PS;Karagueuzian,HS
通讯作者：
Karagueuzian,HS