Wave amplitude relationships in the normal electrocardiogram.

The characteristics of the standard 12-lead electro- cardiogram have been determined by studies based on large numbers of apparently normal sub- jects (Kossmann and Johnston, 1935; Myers et al., 1947; Sokolow and Friedlander, 1949; Hiss, Lamb, and Allen, 1960). Means, standard deviations, and percentile distributions have been calculated for all waves. Relationships between amplitudes of waves appearing in different leads have, been described qualitatively (Kossmann and Johnston, 1935), and used quantitatively to determine the mean frontal plane QRS axis (Wilson et al., 1944) and to establish criteria for diagnosis of left or right ventricular hypertrophy (Sokolow and Lyon, 1949a, b). However, with one notable exception (Simonson, Cady, and LaRiviere, 1964), no systematic quantitative studies have been made of amplitude relationships between different waves in the normal electrocardiogram. The present study was under- taken in an attempt to delineate such relationships and to determine their clinical usefulness. Criteria are suggested whereby waves that are within cur- rently accepted limits of normal may be identified as abnormal on the basis of abnormal relationships to other waves.