Role of Sympathetic Nerve Activity for Modulation of Transmural Ventricular Repolarization and Initiation of Ventricular Fibrillation

使用多极插入针电极记录通过室壁(心内膜层、心肌中层：MID和心外膜层：EPI)的单极心电图。通过分析心电图的激活-恢复间期(ARI)来评估局部心室复极。电刺激犬室性快速性心律失常(VTA)模型的双侧星状神经节和颈迷走神经干，改变自主神经活动。利用体表心电图数据进行频谱分析(Mem Calc法)评价自主神经活动，电刺激左侧星状神经节诱发非持续性室速。应用E4031后，VTA偶尔退化为室颤(VF)，而索他洛尔可阻止VTA的诱导。在QT间期延长、交感神经刺激的低输出量缩短QT间期的花青素-A(AP-A)模型中，…在AP-A模型中，阻断迷走神经刺激后交感神经活动逐渐增强，T波交替(TWA)，有时可诱发室颤。TWA在心脏造成了较大的空间离散度，室颤的发生与中层的延迟状态和/或功能性传导阻滞有关。中层和外层不同的电生理特征，ARI恢复动力学(中层较大的Δ和τ)和舒张期，有助于启动协调的TWA值。此外，当QT间期在中层和外层连续两次缩短时，产生更大空间离散度的非协调性TWA在中层和外层之间发展。美西律缩短AP-A模型的基线QT间期，并阻止与交感神经活动相关的TWA和VF的启动。体表心电频谱分析参数较好地反映了心内自主神经活动。较少

Unipolar electrograms through the ventricular wall (endocardial layer, mid-myocardial layer : Mid, and epicardial layer : Epi) were recorded using multipolar plunge needle electrodes. Local ventricular repolarization was estimated by analyzing the activation-recovery interval(ARI) from the electrograms. Autonomic nerve activity was altered using electrical stimulation of both sides of stellate ganglions and cervical vagosympathetic trunks of canine experimental models of ventricular tachyarrhythmia(VTA). To evaluate the autonomic nerve activity, spectrum analysis (Mem Calc method) was performed using the data from body surface ECG.Electrical stimulation of the left stellate ganglion induced non-sustained VTA in the control state. After administration of E4031,VTA occasionally degenerated into ventricular fibrillation(VF) whereas sotalol prevented induction of VTA. In an anthopleurin-A(AP-A) model of a prolonged QT interval, low output of sympathetic stimulation abbreviated QT interval … More and homogenized the ventricular repolarization in the heart, but high output stimulation provoked VF.Sympathetic nerve activity gradually increased after cassation of vagal stimulation, and T wave alternans(TWA), and sometimes, VF were induced in an AP-A model. TWA created a large spatial dispersion of the ventricular repolarization in the heart, and initiation of VF was associated with a delayed condition and/or functional conduction block at the Mid layer. Different electrophysiological characteristics between the Mid and Epi layers ; ARI restitution kinetics (larger ΔARI and τ at Mid) and diastolic intervals, contributed to initiate concordant TWA. Furthermore, discordant TWA which created a much larger spatial dispersion of ventricular repolarization developed between the Mid and Epi layers when QT interval shortening occurred in two successive beats at the Mid or Epi layers. Mexiletine shortened baseline QT interval in an AP-A model and prevented initiation of TWA and VF associated with sympathetic nerve activity. Intracardiac autonomic nerve activity was reasonably represented on the parameters of spectrum analysis of body surface ECG. Less