有效不应期的长短是心肌细胞兴奋性变化的重要标志之一。目前测定有效不应期方法一般采用细胞内微电极技术,用离体和在位两法记录心肌细胞动作电位,并给予双脉冲刺激进行测定。在整体动物心脏上测定有效不应期,因心脏处于自发窦性节律下活动,不能用双脉冲直接刺激心肌进行测定,这种方法不能反映在自然搏动下有效不应期的的变化。有作者设计制作“需求型脉冲发生器”利用同步记录心电图R波触发产生一个电脉冲。该脉冲再触发电子刺激器产生延迟方波,来测定在位心肌细胞的有效不应期。出于对仪器设置简便价廉及在自然搏动下测有效不应期的考虑,我们设计了,以动作电位○相同步触发来 Effective refractory period is one of the important signs of changes in cardiac myocyte excitability. The current measurement of effective refractory period methods generally use intracellular microelectrode technology, with in vitro and in situ recording of cardiomyocyte action potential, and to give double-pulse stimulation was measured. In the whole animal heart determination of refractory period, because the heart is under spontaneous sinus rhythm activity, can not be directly stimulated by double-pulse myocardial measurements, this method can not reflect the effective beat under natural beating changes. Some authors design a “demand-type pulse generator” using synchronous recording ECG R-wave trigger to generate an electrical pulse. The pulse then triggers the electronic stimulator to generate a delayed square wave to determine the effective refractory period in cardiomyocytes. For simplicity and low cost of instrument setup and measurement of effective refractory periods under natural beats, we designed the system to operate potentials with phase-by-phase trigger