On Development Of The Measure Instrument Of Heart Pumping Reserve

The major role the heart plays in circulatory system is to pump blood through the body to meet the needs of metabolism. A common problem to occur in medical practice and experimental research is to determine whether the heart pump is functioning properly and whether its action is getting enhanced or impaired. The main problem of most patients suffering from heart failure is the decreased force of cardiac contraction. Meanwhile, the heart inotropic, chronotropic and dromotropic effect is in a state of intricacy and constant flux due to a variety of patients' condition or treatment. Since any heart disease may finally cause heart failure, it's an absolute essential procedure to carry out real-time monitor and estimation of the heart inotropic, chronotropic and dromotropic effect in the diagnosis and treatment of cardiovascular diseases. This paper works under the above background. For the purpose of convenient, harmless measurement and estimation of heart reserve at low cost, the paper performs more comprehensive tests on heart reserve by applying synchro record of EEG and cardiac output 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(Chongqing University). The errors from outside interference are reduced and reliability of the analytic result is enforced by performing analysis, process and determination of the internal relations among the three signals. This paper devised a hardware unit, which is capable of carrying out simultaneous measurement of EEG, heart sound and heart impedance. The circuit adopted the hardware structure of PIC singlechip processor and USB transmission interface. The system enjoys such advantages as compactness, convenience, fast speed and stable performance. The system software realized the basic function module blocks with C++ Builder, which included system management of the upper microprocessor, data communication through USB, data playback and analysis and the database. The author eliminated the spurious errors of ECG by wavelet analysis, and remove noise of heart sound signals by wavelet analysis and Sthene likelihood estimation.