Vinet A, Cardinal R, LeFranc P, Hélie F, Rocque P, Kus T, Pagé P
Research Centre, Hôpital du Sacré-Coeur de Montréal, Québec, Canada.
Circulation. 1996 May 15;93(10):1845-59. doi: 10.1161/01.cir.93.10.1845.
The aim of this study was to determine whether cycle length (CL) variations at the onset of monomorphic ventricular tachycardias follow distinctive patterns.
We retrospectively analyzed 59 monomorphic ventricular tachycardias induced in 40 patients in whom intraoperative mapping was performed with 63 epicardial and 64 endocardial electrograms recorded simultaneously. Activation times and CL were determined at each electrode site over several beats (36+/-10 beats, mean+/-SD) starting with the first after programmed stimulation. In the majority of the tachycardias, CL variations were accounted for by fitting to an exponential function: CL=CLs+Ae-b/tau, where CLs is the stable CL, b is beat number, tau is the time constant (in beat number), and A is the magnitude of CL relaxation. A decelerating trend (with reference to rate) (negative A) accounted for 21 tachycardias, an accelerating trend in rate (positive A) accounted for 12 tachycardias, and 4 others displayed a double dynamic behavior, with an initial acceleration followed by a decelerating trend in rate. Among the ventricular tachycardias that were not fitted to exponential models, 12 showed a constant trend and 10 others showed irregular CL fluctuations. The monomorphic character of the tachycardias was established by principal-component analysis, which also indicated that CL dynamics associated with the accelerating and decelerating trends may be related to shortening and prolongation of activation times, respectively, occurring in equal proportion at all recording sites. In canine preparations in which reentry circuits could be mapped with high resolution, CL showed an accelerating trend in rate when circus movement of excitation occurred around a transmural scar in muscle generating unipolar electrograms with relatively high -dV/dtmax, and a decelerating trend in rate occurred when functional reentry occurred in muscle generating unipolar electrograms with depressed -dV/dtmax.
Beat-to-beat CL variations may occur at the onset of sustained monomorphic ventricular tachycardia as a result of uniform acceleration or deceleration of activation times while the overall activation pattern remains constant. The associated initial trends in the rate of sustained monomorphic ventricular tachycardia follow typical patterns that might provide "signatures" corresponding to reentry substrates with distinctive functional properties.
本研究旨在确定单形性室性心动过速发作时的周期长度（CL）变化是否遵循独特模式。
我们回顾性分析了40例患者诱发的59次单形性室性心动过速，术中进行标测，同时记录63个心外膜和64个心内膜电图。从程控刺激后的第一个搏动开始，在几个搏动（36±10个搏动，均值±标准差）期间，测定每个电极部位的激动时间和CL。在大多数室性心动过速中，CL变化可通过拟合指数函数来解释：CL = CLs + Ae -b/τ，其中CLs是稳定的CL，b是搏动次数，τ是时间常数（以搏动次数计），A是CL弛豫的幅度。减速趋势（相对于心率）（A为负）见于21次室性心动过速，心率加速趋势（A为正）见于12次室性心动过速，另外4次表现为双动态行为，最初心率加速随后减速。在不适合指数模型的室性心动过速中，12次表现为恒定趋势，另外10次表现为CL不规则波动。通过主成分分析确定了室性心动过速的单形性特征，这也表明与加速和减速趋势相关的CL动态变化可能分别与激动时间的缩短和延长有关，在所有记录部位以相等比例发生。在能够高分辨率标测折返环路的犬类标本中，当兴奋的环形运动围绕产生具有相对高 -dV/dtmax的单极电图的肌肉中的透壁瘢痕发生时，CL显示心率加速趋势，而当在产生具有压低的 -dV/dtmax的单极电图的肌肉中发生功能性折返时，CL显示心率减速趋势。
在持续性单形性室性心动过速发作时，逐搏CL变化可能是由于激动时间均匀加速或减速，而整体激动模式保持不变。持续性单形性室性心动过速心率的相关初始趋势遵循典型模式，可能提供与具有独特功能特性的折返基质相对应的“特征”。
