A Design Of ECG Automatic Diagnosing System Based On LabVIEW

Automatic analysis and diagnosis for Electrocardiogram(ECG) plays an important role in analyzing and diagnosing cardiovascular disease. With the widespread use of ECG in clinical diagnosis, increasing importance has been attached to how to automatically classify vast amounts of ECG record more quickly and accurately with computer.In this paper, a system based on LabVIEW was designed to diagnose ECG automatically. The main tasks are the following:(1) Read the ECG signal from MIT-BIH database. There are txt files and waveforms in the MIT-BIH database. Read the data by the VI which operates files by LabVIEW file I/O and displays the waveform.(2) ECG signal preprocessing.The collected ECG signal are often accompanied with three kinds of noise such as baseline drift(Baseline Wander), 50Hz power line interference and electromyographic interference. The severe baseline drifting will cause wrong and missed examination of QRS wave group comprehensive. In this paper, a method based on cubic spline interpolation was used to eliminate baseline drift.(3) Feature point detection. The system firstly carry out the identification of QRS wave, P, T wave and ST segment, then calculate the R-R interval, heart rate and finally diagnose S-T segment. In the process of detections, a primary method based on wave peak detection was used to detect R wave at the same time avoiding the tall T wave and interference of cut marks. S-T segment is in the transition zone between S wave and T wave, because it does not have typical QRS amplitude or spectral characteristics. Sometimes, this transition zone is very smooth and moderate. In the paper, a principle called identifying a turning point in curves with the triangle was used to indentify J point. (4) ECG Diagnosis. The diagnostic results are obtained according to the situation of feature point detection and medical knowledge.This ECG automatic diagnosis system can detect QRS wave correctly and diagnose disease according to waveform characteristic parameters and medical knowledge to provide doctor with diagnostic advice.