AbstractsEngineering

This paper discussed the human electrocardiogram, the instrumentation used to graphically record it, and the design and performance of a specialized system for vector cardiography: the Vector Electrocardioscope (VECS) System. The introduction reviews in considerable detail the pertinent known physiology of the heart, especially the electrophysiology responsible for the genesis of the electrocardiogram. The development of electrocardiography in both its concepts and apparatus is traced from the early 19th century to the present day. Vector cardiography is defined with a discussion of its concepts, theoretical bases, and present day instrumentation. The general design considerations of gain, noise and bandwidth as applied to electrocardiography are considered, as well as, display conventions and electrical hazards. Customer specifications and the wishes of the system designer are shown to interact to influence the particulars of system design. In discussing the VECS System it is first "blocked out" to meet specifications, and then the specific requirements of each functional operation described. The modifications required to adapt commercial instruments to their system task are detailed. The design of two instruments peculiar to the VECS System are reported. The VECS Control Panel is the operational heart of the VECS System and provides signal conditioning (system gain and positioning) and display (system mode, blanking, z-axis intensification, time markers, calibrator) functions. The VECS Input Selector features patient electrode connections, internal calibration, and electrocardiographic lead selection. CRT photographs illustrate the basic performance of the VECS System: 180 KC and 25 FIT peak-to-peak noise. Other photographs illustrate the systems use with a patient and the technique of selectable vectorcardiography. Desirable refinements of the present system, proposed modifications for future systems, and speculations as the future extension of the VECS System are discussed.