Study Of Portable Recorder For Cardiac Reserve

The most important aspect of cardiac dysfunction in heart failure was not the depressed cardiac performance noted at basal resting states,but rather the loss of cardiac reserve.As any heart disease may finally lead to heart failure,it is essential to develop methods,especially non-invasive methods to allow serial measurements of cardiac reserve.Since the research conclusion that the amplitude of the first heart sound is the standard measurement of cardiac contractility, study of cardiac reserve with heart sound signals begins to be a new separate research.At present, researchers mostly detect heart sound before and after exercises to study the cardiac reserve, as equipments to record long-time dynamic heart sound signals in body were not available yet.This paper develops under the above background.To make measurement and estimation of the continous cardiac reserve during exercise non-invasive, convenient and low-cost, the paper performs more comprehensive tests on cardiac reserve by applying synchro record of electrocardiogram(ECG) and accumulated human physical activity(AHPA) movement signals on the basis of phonocardiogram exercise test(PCGET), a method founded on relative value of the first heart sound, which is proposed by Professor Xiao Shouzhong of Chongqing University.This paper designed a portable device to evaluate people's dynamic cardiac reserve.It consists of a MSP430 microchip, a CompactFlash card, PCG detecting circuit, ECG detecting circuit and physical activity movement signal detecting circuit etc.Our experiments showed that it has following virtues:low power consumption, compact volume,long-time recording,conveniecnce, stable quality, can display the system state in real time,and can handle some problems of mistakes,etc.Meanwhile,we designed a software for data processing and analysis,which includes system management module,data acquisition module,data review module,data pre-processing and analysis module and database management module etc.The developing environment was C++ Builder 6.0.In the softerware system,the data recorded by the recorder can be loaded in and then be processed and anysised,and in the end indexes to evaluate the cardiac reseve were advanced,which affords the solid foundation for further evaluation and study of dynamic cardiac reserve in various vocations.