Development of a Real-time Monitoring System of Spatial ST Vector

Abstract

A real-time continuous monitoring system of the ST-segment of electrocardiogram has been developed at our laboratory. This system calculates a spatial ST magnitude and two angles (azimuth and elevation) from three-channel Frank electrocardiograms following the formula with a micro-computer. Spatial ST magnitude=√ST_X²+ST_Y²+ST_Z², Azimuth=tan^-1ST_Z/ST_X, Elevation=tan^-1 ST_Y/√ST_X²+ST_Z². These data are displayed on a CRT displaying system (4 channels) and a penwriting recorder (6 channels) simultaneously. This system could record changes of spatial ST magnitude on experimental coronary artery occlusion. It is concluded that this system will be useful as a non-invasive monitoring of myocardial ischemia or injury in intensive care units.