A method for determining a degree of entropy of medical data from a waveform signal comprises steps of receiving the said medical data as a waveform, detecting a standard point, i.e. an apex of the wave, determining the beat-to-beat time period of the wave, converting the time period to a transient heart rate frequency, forming time series by using the sequential data of the said converted transient heart rate frequencies, and coding the said time series in the form of differences between sequential data. In addition, the said coded differences are compressed using a lossless compression method to form a result representing a degree of the compression.
