| Summary: | 碩士 === 長庚大學 === 電機工程研究所 === 90 === The periodic mechanism activities of heart play an important role in maintaining the life phenomena of human body. Electrocadiogram(ECG) provides a noninvasive means to understanding the detailed situations of heart activities, and the firing activities of the sinus node modulated by the autonomic nervous system. In general, the modulation of autonomic nervous system will change the characteristics of heart rate. Recently, several digital signal processing algorithms have been applied on heart rate signals to find the relation of heart rate variability(HRV) to the autonomic function, and investigate the change of HRV in pathological situation. In addition, heart rate would change rapidly according to the external stimulation and physiological alternation, so HRV could be a new monitoring index to reveal the physiological condition during syncope, myocardiac infarction, anesthesia. Combining with other physiological signals, it can provide more information, and aid for diagnosis.
Since a HRV analysis system needs several heavy computations, such as QRS detection, heart rate analysis and parameter extraction, It is difficult to implement with a general-purpose microprocessor. The goal of this study is to develop a real-time heart rate variability analyzer base on digital signal processor(DSP). So the physician can obtain instantaneous information of autonomic function from HRV. To achieve a real-time HRV analysis, an .accurate QRS detection is needed in this system. A QRS detection combing with Tompkins peak detection and template match was implemented. In order to meet the instantaneous characteristic and local stationary of HRV, the heart rate signal was multiplied with a Half-triangular window before fast Fourier transform to enhance newly coming heart rate data. Aiding with wireless communication device, this system can help the physician to monitor the electrocardiogram(ECG) and heart rate variability of patients with cardiovascular diseases, without activity limitation（e.g. can set up this system on the wheelchair）.In the future, this system can be smaller by the ASIC design and can be applied on home-based care system, bio-control, etc.
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