Effect of inadequate frequency response of direct writing electrocardiograph on rat electrocardiogram.

: Fairly good electrocardiograms of rats can be recorded by using a band width of 0.5 to 75 Hz. Change in low frequency did not alter the wave pattern or duration. Change in high frequency altered the durations and wave pattern grossly. 50 Hz filter is useful in avoiding AC interference but creates artificial notches in all the waves.