Correlation technique and its application in the His bundle electrocardiogram

In literature, the HBE has been displayed by application of the averaging method. In this paper, correlation analysis technique was used and the body-surface HBE was displayed in a special-purpose electronic computer. The correlation coefficients of the P-A, A-H, H-V intervals and the H-wave width of both methods are almost equivalent and one can be substituted by the other. Compared with the averaging method, the S/N ratio of the correlation method is greater and the residual noise is nearly absent. Furthermore, the effects of the integrating time T and delay time delta tau on the S/N ratio, the measuring resolution and the analytical time have been studied. Correlation analysis technique is a method based on the cybernetic and information theory. With this technique, by using correlation function, the dependence (auto-correlation function) of the value at one instant upon that of the other during the same random process, or the interdependence between sets of data from 2 random processes can be described. Up to the present, there has been no report on the activities of the ventricular conductive system with the S/N ratio smaller than 1, detected on the body surface by correlation analysis technique[1 - 3]. However, using this technique, the author successfully detected the body surface HBE with a special-purpose mini-computer in 1977.