Summary

Vectorcardiography, popularized in the 1950-ties, became a new clinical method of three-dimentional recording and representation of the spread of electrical activation in the heart and of its electrical field. In this study, the experiments were performed on the exposed hearts of anesthetized rabbits. Vectorcardiographic recordings (“micro-vectorcardiograms”) were obtained from the epicardial surface and from the depth of the myocardium using specially constructed multi-point epicardial electrodes (with rectangular or circular arrangement of the recording points) and a three-dimentional  intramyocardial electrode. Some adaptation of the routine clinical recording equipment was needed because of the high voltages recorded and low impedance of the circuit. Obtained micro-vectorcardiograms allow easy determinations and mapping of the directions of local spread of activation. Time of its arrival locally could be determined by application of external stimulus, synchronized with the spontaneous heart rhythm and with increasing latency (fusion beats). Potential applications of the new experimental technique are discussed in normal conditions and in induced pathology. Incidental finding was a demonstration at the myocardial level of the existence of T wave alternans during induced myocardial ischemia.

Publication:

1. Application of the Vectorcardiographic Method to the Analysis of the Spread of Activation in Small Portions of the Heart Muscle. Waldemar J. Wajszczuk. Proceedings of the Symposium on Biomedical Engineering, Milwaukee, Wisconsin, June 23-25, 1966, vol. I, Cardiovscular Physiology, XVII-3, pp. 373-377.