Criteria of identification of individual heart cycle phases on ECG

Aims Criteria of identification of individual heart cycle phases according to an ECG curve are described in this paper. Materials and For this study, a single-lead system ECG is used only. Its distinctive methods feature is that an ECG signal is recorded within the body surface area of the ascending aorta. Using the theory of biological system process continuity, the individual heart cycle phase boundaries are determined at those points of the cardiac signals where we deal with an energy process transition in the cardiovascular system from the process of the energy build-up to its attenuation, and vice versa. The transition points are identified by us by mathematical differentiation of the ECG signals, and, as a result, they correspond to extrema of the ECG derivative. Some individual heart cycle phases are found according to maxima on the derivative, others are identified according to minima on the derivative curve, respectively. Results The method of application of the ECG derivatives allows to capture individual heart cycle phases in a very precise manner. Utilization of the ECG derivatives is a prerequisite for computer-assisted processing of the data to deliver measurements of durations of every heart cycle phase. Conclusion Using the ECG derivatives for fixing every heart cycle phase makes possible to fill up the gaps in the theory of phase analysis and avoid misinterpretations of any type of the ECG phase structures.