Electrocardiography: this is a method of recording the potential difference between two points in the electric field of the heart during its excitation. The modern technology allow you to record ECG on a long time interval in condition of person normal life(portable cardio); when carrying out functional tasks with doses physical exertion (bicycle ergometer, treadmill) and tests with the introduction of medicament preparations. To solve the problem, the following non-proportionality can be used: by the first - order derivative, by the value of the first order, as well as the disproportionality for the function y(t) by x(t), given parametrically. In this paper was an analyzed ECG assistant with the characteristics of the proportionality of numerical functions.