Spectral analysis of the normal electrocardiogram of rabbits

A spectral analysis of the QRS complex of the rabbit's electrocardiogram was made. The amplified ECG signals were filtered through low-pass filters with cut-off frequency 500 Hz and steepness 12 dB/oct, and fed to a multichannel oscilloscope monitor. The images obtained were photographed. They were subjected to analog-to-digital conversion. The values were fed for processing to an EC 1035 computer. A standard discrete Fourier transformation was used. The spectral curve exhibited a considerable amplitude of the higher harmonics. Point -20 dB was at 164 Hz and point -30 dB was at 314 Hz. It was concluded that for accurate reproduction of the rabbit's ECG the recording electrocardiograph would have a bandwidth up to 225 Hz. An amplitude error not exceeding 10 per cent would be guaranteed.