Weak Ecg Signal Detection Study

There are a lot of ways ihat measure low ampitude cardial signals, for example, P-SAECG, VLP, HFECG, His and so on. And they can not injury body. It is useful for cardial diseases to diagnose by the ways, for example, predicting PAF, monitoring MI and so on.There are many mistakes about the sensitivity, specificity and predictive accuracy for diagnosing cardial disease in many diagnosing systems now. Our aim is going to resolve it. We have finished a lot of works: 1) designing and making up a dianosing system for P-SAECG, VLP, HFECG, His in Windows 98. 2) the system have high sampling frequency and the function of real-time displaying wave. 3) designing a signal averaged program that have many reference dots. 4) accomplishing clinic test about P-SAECG, VLP, HFECG, His.After used in clinical practice, the device showed its sensibility and reliable. The major significant findings and conclusions were the following:1. P-SAECG: (I) there was significant difference in the P wave duration of P-SAECG between normals and PAF, (2) the sensitivity, specificity and predictive accuracy for diagnosing AF was much higher than that of ECG;2. VLP: (1) there was significant difference in the result of VLP between normals and post MI, (2) the sensitivity, specificity and predictive accuracy for diagnosing CAD was much higher than that of ECG;3. HFECG: (1) The notches increased with increasing degree of coronary artery and changed with changing patient's condition, therefor we concluded that HFECG could reflectthe degree of CAD, (2) the sensitivity for diagnosing CAD was much higher than that of ECG, therefor we concluded that HFECG was a sensitive index of diagnosing CAD; 4. His: the system can record His on the body surface.There are two newly facts about the research. Firstly, it is not report that anyone had designed a diagnosing system for P-SAECG in China before we have designed the system. On the other, we developed following algorithms: 1) the algorithm of setup parameters of template and signal-averaed program, 2) the algorithm of automatically restrain ring wave by digital filter generated in P-SAECG.The most important and difficult content in the research is designing P-SAECG system. There is not any resource about P-SAECG in China. There are few persons who work in P-SAECG in abroad. But P-SAECG is very useful in predicting PAF.