Method of automatic determination of the heart’s electrical axis in cardiological decision support systems

Abstract

The work is devoted to solving the scientific and practical problem of automating the heart’s electrical axis calculation to improve the quality of morphological analysis of biomedical signals with locally concentrated features in cardiological decision support
systems, which in turn reduces the likelihood of medical errors. The work shows that existing methods for in the determining the
electrical axis of the heart require morphological analysis of an electrocardiogram. The method is based on determining the integral
signal in the frontal plane from all limb leads, taking into account the lead angle in the hexaxial reference system. In graphic form in
polar coordinates, the integral electrocardiological signal is a figure, predominantly elongated along the axis, the direction’n of which
corresponds to the heart’s electrical axis. The position of the heart’s electrical axis is calculated as the angle between the axis of
standard lead I and the vector, the end of which is at the center of mass of the locus of the points the farthest away from the reference
point. Cluster analysis is used to find the most distant points from the reference point. The proposed method for of calculating the
heart’s electrical axis makes it possible not to carry out a preliminary morphological analysis of an electrocardiogram. To implement
the method proposed in the article, a program was written in the Matlab language, which is connected as a dynamic link library to the
cardiological decision support system “TREDEX telephone” operating as part of the medical diagnostic complex “TREDEX” manufactured by “Company TREDEX” LLC, Kharkiv. Verification of the results was carried out using a database of electrocardiograms,
which were recorded using a transtelephone digital 12-channel electrocardiological complex “Telecard”, which is part of the medical
diagnostic complex “TREDEX”, and deciphered by cardiologists of the communal non-profit enterprise of the Kharkiv Regional
Council “Center for Emergency Medical aid and disaster medicine”. Comparison of the results of calculating the heart’s electrical
axis according to electrocardiograms by a doctor and automatically using the proposed method showed that in the overwhelming
majority of cases the decisions made coincide. At the same time, cardiologists make mistakes, and errors are made during automatic
calculation using the proposed method. The paper explains the reasons for these errors