Lab M J, Child R K
Am J Physiol. 1979 Jan;236(1):H183-8. doi: 10.1152/ajpheart.1979.236.1.H183.
The duration of a cardiac action potential (AP) is measured from the beginning of its upstroke to the end of its asymptotic repolarization phase: the end being given by a point in proportion to the AP amplitude. If the resting potential, AP amplitude, as well as the duration, alter simultaneously, frequent accurate measurements can be extremely tedious. A fully automatic AP duration meter has thus been constructed to cope with these difficulties while measuring within about 2% on a beat-to-beat basis. It is suitable either for brief sampling of AP durations when recording with microelectrodes, which may impale cells intermittently, or for continuous monitoring, as with suction electrodes on intact beating hearts in situ. For example, the device can faithfully track changes in duration during periods of regional myocardial ischemia in intact ventricles in situ while the AP alters its base line, upstroke velocity, amplitude, and duration.
心脏动作电位（AP）的持续时间是从其上升支开始到渐近复极化阶段结束来测量的：结束点由与AP幅度成比例的一点给出。如果静息电位、AP幅度以及持续时间同时改变，频繁进行精确测量会极其繁琐。因此，已经构建了一种全自动AP持续时间测量仪，以应对这些困难，同时在逐搏基础上实现约2%以内的测量精度。它既适用于在用微电极记录时对AP持续时间进行简短采样（微电极可能会间歇性刺入细胞），也适用于连续监测，比如对完整原位跳动心脏使用吸引电极时。例如，该设备能够在原位完整心室的局部心肌缺血期间忠实地跟踪持续时间的变化，此时AP会改变其基线、上升速度、幅度和持续时间。
