SLOW CONDUCTION, FRACTIONATION, AND SIGNAL-AVERAGED ECG

室性心律失常是#年发病率和死亡率的主要来源。 这个国家。大多数是由再入引起的，其中一个先决条件是 传导缓慢。确定传导迟缓的特征可能有助于 室性心律失常的认识和治疗。分馏的 心外膜电图常见于室性心脏病患者。 心律失常，可能是由于传导缓慢的心肌引起的。 最近，检测到异常的QRS/ST波 脑室病人体表信号平均心电图的研究 心律失常，也可能由传导缓慢的心肌引起。 异常的QRS/ST电位在未来可能提供无创性的 个别受试者传导缓慢的特征。然而， 慢传导、分段性心外膜电信号之间的关系 体表QRS/ST波异常需确诊及 量化的。此应用程序建议研究三个特定的假设 在犬慢性心肌梗死模型中：(1)分次 心电图起源于传导缓慢的心肌区，(2)异常 QRS/ST波是分化型心绞痛的体表表现 心电图，以及(3)心外膜之间存在相关性 分离心电图机定位和体表定位 QRS/ST波异常。 这项提议中将使用几种新技术。第一，本地化 右室游离壁的传导速度将被估计。 利用单极同步记录的局部激活时间 心外膜导联。第二，分馏的空间分布 心电图将来自相同的心外膜导联。第三, 多个同时单极心电将用于检测和 体表QRS/ST波异常定位。

Ventricular arrhythmias are a major source of morbidity and mortality in this country. Most are caused by reentry, one prerequisite for which is slow conduction. Characterizing slow conduction may help in the understanding and treatment of ventricular arrhythmias. Fractionated epicardial electrograms are often detected in patients with ventricular arrhythmias, and they may arise from slowly-conducting myocardium. Recently, abnormal QRS/ST potentials have been detected with signal-averaged ECG on the body surface of patients with ventricular arrhythmias, and these may also arise from slowly-conducting myocardium. Abnormal QRS/ST potentials may in the future provide a noninvasive characterization of slow conduction in individual subjects. However, the relationships among slow conduction, fractionated epicardial electrograms, and abnormal body surface QRS/ST potentials need to be confirmed and quantitated. This application proposes to study three specific hypotheses in a canine model of chronic myocardial infarction: (1) fractionated electrograms arise from areas of slowly-conducting myocardium, (2) abnormal QRS/ST potentials are the body surface manifestation of fractionated electrograms, and (3) there is a correlation between the epicardial location of fractionated electrograms and the body surface location of abnormal QRS/ST potentials. Several novel techniques will be used in this proposal. First, local conduction velocity in the right ventricular free wall will be estimated using local activation times recorded simultaneously from 64 unipolar epicardial leads. Second, the spatial distribution of fractionated electrograms will be derived from the same 64 epicardial leads. Third, multiple simultaneous unipolar ECG's will be used for detection and localization of abnormal body surface QRS/ST potentials.