Lux R L, Green L S, MacLeod R S, Taccardi B
Nora Eccles Harrison Cardiovascular Research and Training Institute, Salt Lake City, Utah 84112.
J Electrocardiol. 1994;27 Suppl:100-5. doi: 10.1016/s0022-0736(94)80065-0.
Measurement of dynamics and spatial characteristics of ventricular repolarization is of interest in assessing patients with ischemic heart disease, particularly in relation to the detection and characterization of ischemic events, identification of patients at risk of ventricular arrhythmias, or determination of the efficacy of drugs intended to alter repolarization. The QT interval (QTI) has been the index of choice for assessing repolarization abnormalities. It is a general measure of repolarization duration but lacks the power to assess the spatial aspects of repolarization and the ability to detect localized shortening in the setting of global prolongation. For direct cardiac surface measurement, QRST integrals and activation recovery intervals (ARIs) were used to assess repolarization and its disparity. The use of similar measurements from the body surface was proposed to provide better characterization of repolarization, its disparity, and its dynamics than is possible using the QTI. In one open-chest experiment using an intact canine heart and two experiments using isolated canine hearts suspended in a torso-shaped electrolytic tank, 64 epicardial electrograms and 192 torso surface electrocardiograms were measured simultaneously. Ventricular repolarization was globally altered by varying pacing cycle lengths or tank temperature. Atrial and ventricular pacing were used to assess sensitivity of repolarization indices to activation sequence. At the cardiac surface, (1) QTI tracks global repolarization changes but is affected by activation sequence and insensitive to localized shortening of repolarization; (2) distribution of QRST integrals reflects disparity of repolarization and is largely independent of activation sequence; and (3) ARI measures local repolarization duration and is only weakly affected by activation sequence.(ABSTRACT TRUNCATED AT 250 WORDS)
测量心室复极的动力学和空间特征，对于评估缺血性心脏病患者具有重要意义，特别是在检测和表征缺血事件、识别有室性心律失常风险的患者或确定旨在改变复极的药物疗效方面。QT间期（QTI）一直是评估复极异常的首选指标。它是复极持续时间的一般度量，但缺乏评估复极空间方面的能力，以及在整体延长情况下检测局部缩短的能力。对于直接心脏表面测量，QRST积分和激活恢复间期（ARI）被用于评估复极及其差异。有人提出使用来自体表的类似测量来更好地表征复极、其差异及其动力学，这比使用QTI更可行。在一项使用完整犬心的开胸实验以及两项使用悬浮在躯干形状电解槽中的离体犬心的实验中，同时测量了64个心外膜电图和192个躯干表面心电图。通过改变起搏周期长度或电解槽温度来全局改变心室复极。使用心房和心室起搏来评估复极指标对激活顺序的敏感性。在心脏表面，（1）QTI跟踪全局复极变化，但受激活顺序影响，对复极局部缩短不敏感；（2）QRST积分的分布反映复极差异，且在很大程度上独立于激活顺序；（3）ARI测量局部复极持续时间，仅受激活顺序微弱影响。（摘要截短于250字）
