| EASI-derived 12-leads ECG is a theory of getting standard twelve leads with five electrodes. For portable ECG monitoring equipment, system design should be simple and easy to operate. It is because standard twelve leads require ten electrodes and contain the body electrode that the electrode is easy to twine around each other and it is not suitable for long time monitoring. EASI-derived 12-leads only need four chest electrodes and one grounding electrode, then the twelve lead ECG information can be obtained by deriving which is very suitable for portable devices and can be used for long time ECG monitoring.In this study, a new type of detection system is designed based on the theory of EASI-derived 12-leads to get standard twelve leads with few electrodes. It uses a mobile phone as the master unit to carry out the operation of the waveform display and other operations, it is easy to operate and convenient for popularization. Makes the data acquisition unit with an ADS 1294 amplifier chip and MSP430F149 micro-controller to accomplish Analog digital conversion of ECG signal, and transmits data on the Bluetooth communication interface. Its software for data processing and display is programmed in Android.Because the ECG signal is very weak, the system design needs to be considered for filtering and so on. The baseline drift, EMG interference and the 50Hz interference were removed by using a digital filter and a digital notch filter, respectively. Then, the system achieves the calculation of heart rate through the detection of R wave.The function of ECG acquisition is realized by the experiment which uses the prototype of only five electrodes to collect the ECG of the normal people. The result of comparison with the standard twelve leads ECG machine of ten electrodes shows that the average errors of the diagnostic parameters are 3.76% and waveforms match very well. The new system has a wide-application prospect in clinical diagnosis and family health care. |
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