[Wavelet analysis of ECG in mouse with acute myocardial ischemia]
Dianzhong Zhang1, Xiaohong Tan, Guangwen Chen
1Department of Biomathematics and Biologic Information, College of Mathematics Science and Computing Technology, Central South University, Changsha 410078.
Abstract:
The myocardial ischemia model was established by ligating the left anterior descending artery of mice for 10 min. The ECG signal were collected from the mouse with acute myocardial ischemia and from the healthy mouse as controls. The frequency of data acquisition was 500 Hz. The measurement time around 20 seconds was chosen. The wavelet transform technique, a time-frequency method with logarithmic frequency resolution, was used to analyze the ECG signal. Mexican Hat wavelet was used and the scale factor was chosen from an interval [0.00125, 2.5] for evaluating its wavelet coefficient at corresponding scale respectively, thus the central frequency of the band-pass filter was within a range of 200-0. 1Hz. Then we evaluated the signal energy in the bandwidth delta fat frequency f. A variational rule was obtained, i.e. rat's ECG signal energy varies with frequency before and after myocardial ischemia. The results showed that in the mice suffering from acute myocardial ischemia the average signal energy increases in 0.1-1. 0Hz and 1-10 Hz segments and decreases in 10-200 Hz segment.
