50Hz滤波电路对心肌细胞自发动作电位波形分析的影响

目的：研究微电极放大器中的50Hz滤波电路对心肌细胞自发动作电位波形及各项参数的影响。方法：将心肌细胞自发动作电位经玻璃微电极、微电极放大器、微分器、A／D转换器输入微型计算机。在应用和不应用微电极放大器中50Hz滤波功能两种情况下，对心肌细胞自发动作电位波形进行比较分析。结果：在使用微电极放大器中50Hz滤波功能情况下，动作电位波形在0相严重失真，时程延长，除极化最大速度减小；复极化50％、90％的时间延长；其它参数无显著变化。结论：心肌细胞动作电位波形中含有50Hz信号成分，在研究心肌细胞动作电位信号时，不能使用50Hz滤波器。如果使用50Hz滤波器，会造成动作电位波形严重失真，影响实验结果。

Effects of 50Hz-filter circuit on spontaneous cardiac action potential analyzing

Objective: To study the effects of the 50 Hz-filter circuit in a microelectrode amplifier on spontaneous cardiac action potential waveform and parameters. Methods: Spontaneous cardiac action potential signals were fed into a microcomputer through a glass microelectrode, a microelectrode amplifier, a differentiator and A/D converter. The cardiac action potential signals were recorded and analyzed with 50 Hz-filter circuit and without it. Results: When the 50 Hz-filter circuit was used, the phase 0 in the potential waveform was seriously distorted and its duration was prolonged. The maximal rate of depolarization at the phase 0 was decreased. The duration of 50% repolarization and the duration of 90% repolarization were prolonged. The other parameters were not effected. Conclusion: There has already been 50 Hz element in the action potential waveform. During amplifying the cardiac action potential signal, the 50 Hz-filter circuit should not be turned on. Otherwise, the experiment results will be effected.