In our research we analyse electrocardiograms (ECG). The aim of this research is to apply the fractal dimension computing method to electrocardiograms, i.e. to create an algorithm, due to which it would be possible to get a few parameters describing ECG. Then, to check, whether the created the mathematical model for computing fractal dimension classify the possessed data. According to Hausdorf “capacity dimension” we compute and analyze “capacity coefficient”. The research of the plane “capacity coefficient” was carried out in this work (it is a fractal dimension, which was computed at the fixed dimension of the iterational window). The computing algorithm was made, with the help of which the ECG plane capacity coefficient was computed for 300 persons. When the initial information on the examined persons is known, the results are tried to be assessed from the mathematical, as well as medical, point of view.