According to the development of electronic devices and embedded system,a Holter system with high sampling efficiency and good performance is introduced in this paper.Besides,a compact type of ECG device is developed which can precisely record normal ECG,pacing ECG and dynamic ECG.This paper puts emphasis on such key aspects as hardware design with low power consumption,high-efficiency and real-time algorithm,magnitude storage devices and reliable playback interface in high speed.

Objective To investigate the ischemic preconditioning time for inducing rat brain ischemia tolerance.Methods Procerebrum ischemic preconditioning injury was caused by occlusion of two-side common carotid artery for 10 minutes or 20 minutes,and subsequent cerebral ischemic injury was caused by occlusion of middle cerebral artery for 2 hours after 72 hours of reperfusion.The percentage of brain infarct size was calculated for the investigation of the proper ischemic preconditioning time for rat brain ischemia tolerance.Results Ischemic preconditionaing for 10 minutes and 20 minutes can reduce the percentage of brain infarct size significantly.The difference of the percentage of brain infarct size between 10-minute preconditioning group and 20-minute preconditioning group is insignificant,but the mean percentage of brain infarct size in 10-minute preconditioning group is less than that in 20-minute preconditioning group.Conclusion Ten minutes are the suitable time of ischemic preconditioning for rat brain ischemia tolerance.