Research Of Portable Cardiac Reserve Monitoring System Based On DSP

Cardiac Reserve (CR) provides the potential of heart, so the doctors and the patients come to know the detailed influences to heart from different diseases and stress situations and provide particular protection to heart. Theoretical analysis shows that: cardiac reserve value and the first heart sound amplitude size are closely connected; the variation trend of first heart sound amplitude can be used for measuring cardiac contractility and evaluating the cardiac reserve of cardiovascular patients and healthy people. ECG is a commonly used heart function test in analysis of cardiac chronotropic and dromotropic, but it can not be used for detection of cardiac inotropic. Most of the traditional heart function detection equipment required the patients being tested by professional technical personnel at specified places. And it brings lifestyle and economic distress to people whose heart need to be detected many times for a long time. A portable and easy operation cardiac function detection system is researched and designed using TMS320F2812 DSP, which can significant for special groups and healthy people to monitor their own heart health in real-time.System hardware includes analog circuit and TMS320F2812 DSP digital control circuit. The analog circuit consists of power-supply modular, signal pickup circuit, analog filter amplifier, gain control circuit, power ground lifting circuit and signal limit circuit of A/D channel. The processed analog signal would fluctuate in 0~3V at a baseline of 1.5V, then the signal will transmit to TMS320F2812 for A/D conversion and digital processing. The DSP controls signal display by connecting GPIO ports to LCD modular; and realizes the signal storage by connecting SPI serial to SD card.System software consists of TMS320F2812 DSP drivers, A/D sampling by EVA timer-interruption control, LCD real-time display control of the heart sound signal, bottom layer read/write realization of SD card in SPI model, and establishment of FAT32 file system in SD card for signal storage. In addition, signal wavelet de-noising, S1, S2 recognition and cardiac reserve indices calculation algorithm were programed in MATLAB, and converted into CCS projects files which can be downloadable and run on DSP by using CCSLink tools.Cardiac reserve monitoring system gets the heart function evaluation indices by acquiring and analyzing heartsound signal, the system tests shows that it can pickup heart sound signal in quiet environment quickly and accurately, in the meantime signals display on LCD and store in SD card as heart sound wave files . In this thesis, 42 heartsound signals were detected using the automatic recognition and cardiac reserve indices algorithm. The results show that the cardiac reserve indices can be computed quickly and the detection rates of S1 and S2 reached 95.83% and 91.53% respectively, also the accuracy of cardiac reserve indices of healthy college students is much higher than that of elderly people. This portable cardiac reserve monitoring system has the advantages of being small in size, inexpensive, easy for operation, rapid, safe, objective and quantitative. The proposed machanism can be used for detecting and evaluating cardiac reserve in various groups, and has a wide application prospect.