Research And Development Of A Portable Dynamic ECG Monitoring System

ECG monitoring system is able to detect the exception of patients’ heart, in orderto take appropriate and timely treatment, and to achieve the purpose of reducing themortality of heart diseases. But traditional ECG monitor are bulky and high powerconsumption, it only suitable for use in hospitals and other large occasions.In the early stages of heart disease, heart disease harbinger is mainly reflected inQRS-wave becomes longer. While the disease onset by intermittent, there is noregularity and so on, need long continuous ECG detection can be found in theincidence of heart signs. Dynamic ECG on the market are expensive, as well as thedisadvantages of detection of activities ECG, seriously hampering and limiting thesepatients use Dynamic ECG.In the case of patients with early heart disease, we design a set of small,inexpensive ECG testing prototype. The prototype is able to meet the demand for thepatients with early heart disease to do self-testing of this type. The measured couldtest ECG at home alone, combined with the increasing popularity of personalcomputers, and the use of virtual instrument software for data processing and analysis,then the software gives the QRS complex abnormal prompt, measured according tothe prompt, and pet ECG to the hospital to examine in depth.In accordance with the principles of the system simple, low-power, stability andeconomy, the overall design of the system and select the system uses the core chip,built hardware to obtain the ECG signal conditioning circuit, the signal acquisitionand storage functions, the development and testing of PC application softwareLabVIEW. The thesis includes the following aspects:1、For ECG is a weak signal that its frequency between0.5and100Hz, andmixed with a variety of interference filter and amplifier amplifying and filtering of thesurface ECG, by selecting the chip so that the circuit has a high input impedance, highcommon mode rejection ratio, anti-interference ability. 2While using Dynamic ECG instrument, signal saturation distortion appears dueto the continuous activity of the human body. To solve this problem, we join theautomatic gain control circuit in the hardware circuit, automatic gain control circuit toautomatically adjust the gain based on the amplitude of the input signal, the controloutput signal amplitude in the unsaturated range, to avoid the phenomena measuredby the ECG to detect when walking saturated zoom back.3、 Completed the circuit design with the core of MSP430, which including A/Dconversion and SD card storage, achieve the goal of ECG acquisition and storagecapabilities. Then use LabVIEW graphical programming to playback the stored ECG,and to identify and extract ECG feature points, calculate ECG QRS wave, Thenaccording to the result of the above calculation to determine whether the heart rate isabnormal, at the same time provide a basis for whether symptoms of left ventricularhypertrophy.4、The test of the entire system include hardware testing and software testing.Hardware test verify the hardware system circuit can collected ECG signal; thesoftware test results include the outcome of the procedure the R-wave positiondetecting and the judgment of the test for abnormal QRS-wave’s time.