Mirvis D M, Keller F W, Cox J W, Zettergren D G, Dowdie R F, Ideker R E
Circulation. 1977 Aug;56(2):245-52. doi: 10.1161/01.cir.56.2.245.
Junctional depression is often observed during physical exercise in overtly normal subjects. To explore its pathogenesis, 15 normal volunteers were studied during supine, bicycle ergometer, submaximal stress tests. Electrocardiograms were simultaneously recorded from 42 electrodes on the left anterior precordium at two minute intervals at rest and during exercise. Data were used to construct isopotential maps throughout the P-QRS-T intervals. At rest, maps throughout the ST segment were dominated by a single maximum along the upper left sternal border. During exercise, all subjects developed junctional depression that was maximal along the lower left sternal border. Exercise maps during the early to mid-ST segment showed an intense minimum along the lower left sternal border that was continuous with terminal QRS forces in both intensity and location. Later in ST, this minimum decreased in strength and was replaced by a maximum located in the same area as that observed at rest. These observations suggest that junctional depression is the result of competition between two effects, one being normal repolarization which is obscured in the early ST segment by the second, possibly representing delayed terminal depolarization forces.
在表面上正常的受试者进行体育锻炼时，常常会观察到交界区压低。为了探究其发病机制，对15名正常志愿者在仰卧位、自行车测力计进行次极量应激试验期间进行了研究。在静息和运动期间，每隔两分钟从左前胸的42个电极同步记录心电图。数据用于构建整个P-QRS-T间期的等电位图。静息时，整个ST段的图以沿胸骨左缘上部的单个最大值为主。运动期间，所有受试者均出现交界区压低，在胸骨左缘下部最为明显。ST段早期至中期的运动图显示，沿胸骨左缘下部有一个强烈的最小值，其强度和位置与终末QRS向量连续。在ST段后期，这个最小值强度降低，并被一个位于与静息时观察到的相同区域的最大值所取代。这些观察结果表明，交界区压低是两种效应之间竞争的结果，一种是正常复极，在ST段早期被另一种效应掩盖，另一种效应可能代表延迟的终末去极向量。
