Electrocardiographic Leads

This paper is the first of a series of three which will deal with the relationship between the voltages in electrocardiographic leads and the electromotive forces of the heart. The general purpose of this series is to discuss various experimental and theoretic technics which can be used in the analysis of a given lead, and in the building up, or "synthesis," of leads having desired characteristics. The procedures used are based on a fundamental theorem which takes into account not only the irregular shape and conductivity of the body but also the spatial dispersion of the electromotive forces within the heart. It is closely related to the "lead vector" concept of Burger and van Milaan. In this first paper the basic definitions and theorems are developed. The second paper discusses various methods of analysing leads. The third and last presents a number of systematic procedures for designing leads, both vectorcardiographic and unipolar. Such leads can have substantially higher accuracies than those now in use, because their design takes into account the shape and conductivity of the body and its tissues, and the eccentric and extended location of the heart.