Gray R A, Jalife J, Panfilov A, Baxter W T, Cabo C, Davidenko J M, Pertsov A M
Department of Pharmacology, SUNY Health Science Center at Syracuse 13210, USA.
Circulation. 1995 May 1;91(9):2454-69. doi: 10.1161/01.cir.91.9.2454.
Ventricular tachycardia may result from vortexlike reentrant excitation of the myocardium. Our general hypothesis is that in the structurally normal heart, these arrhythmias are the result of one or two nonstationary three-dimensional electrical scroll waves activating the heart muscle at very high frequencies.
We used a combination of high-resolution video imaging, electrocardiography, and image processing in the isolated rabbit heart, together with mathematical modeling. We characterized the dynamics of changes in transmembrane potential patterns on the epicardial surface of the ventricles using optical mapping. Image processing techniques were used to identify the surface manifestation of the reentrant organizing centers, and the location of these centers was used to determine the movement of the reentrant pathway. We also used numerical simulations incorporating Fitzhugh-Nagumo kinetics and realistic heart geometry to study how stationary and nonstationary scroll waves are manifest on the epicardial surface and in the simulated ECG. We present epicardial surface manifestations (reentrant spiral waves) and ECG patterns of nonstationary reentrant activity that are consistent with those generated by scroll waves established at the right and left ventricles. We identified the organizing centers of the reentrant circuits on the epicardial surface during polymorphic tachycardia, and these centers moved during the episodes. In addition, the arrhythmias that showed the greatest movement of the reentrant centers displayed the largest changes in QRS morphology. The numerical simulations showed that stationary scroll waves give rise to monomorphic ECG signals, but nonstationary meandering scroll waves give rise to undulating ECGs characteristic of torsade de pointes.
Polymorphic ventricular tachycardia in the healthy, isolated rabbit heart is the result of either a single or paired ("figure-of-eight") nonstationary scroll waves. The extent of the scroll wave movement corresponds to the degree of polymorphism in the ECG. These results are consistent with our numerical simulations that showed monomorphic ECG patterns of activity for stationary scroll waves but polymorphic patterns for scroll waves that were nonstationary.
室性心动过速可能源于心肌的涡旋样折返激动。我们的总体假说是，在结构正常的心脏中，这些心律失常是由一两个非静止的三维电涡旋波以极高频率激活心肌所致。
我们在离体兔心脏中结合使用了高分辨率视频成像、心电图和图像处理技术，并进行了数学建模。我们利用光学标测来表征心室心外膜表面跨膜电位模式的动态变化。采用图像处理技术来识别折返组织中心的表面表现，并利用这些中心的位置来确定折返路径的移动。我们还使用了结合菲茨休 - 纳古莫动力学和真实心脏几何形状的数值模拟，以研究静止和非静止涡旋波在心脏表面和模拟心电图上的表现。我们展示了与左右心室建立的涡旋波所产生的非静止折返活动一致的心外膜表面表现（折返螺旋波）和心电图模式。我们在多形性心动过速期间识别了心外膜表面折返回路的组织中心，并且这些中心在发作期间移动。此外，折返中心移动最大的心律失常在QRS形态上显示出最大变化。数值模拟表明，静止涡旋波产生单形性心电图信号，但非静止蜿蜒涡旋波产生尖端扭转型室速特征性的起伏心电图。
健康离体兔心脏中的多形性室性心动过速是单个或成对（“8字形”）非静止涡旋波的结果。涡旋波移动的程度与心电图中的多形性程度相对应。这些结果与我们的数值模拟一致，即静止涡旋波的活动为单形性心电图模式，而非静止涡旋波为多形性模式。
