Potential Variations of Extremities and of Precordium in Myocardial Disease

Abstract

Wilson, Macleod, and Barker 1 described electrocardiographic leads which record the potential variations produced by the heart beat at a single point. These leads were obtained by pairing the point in question with a central terminal connected through separate, identical, non-inductive resistances with the right arm, left arm, and left leg respectively. Further details and slight modifications were published. 2 The potential variations of the extremities and of 6 precordial points in normal subjects were studied in Wilson's laboratory. 3 In the past few years Wilson and his associates have taken numerous curves in various types of heart disease by this method, but only a few of these have been published. 4 , 5

Since July 1934, this method has been used in the study of heart disease on the wards of the Third Medical (N. Y. U.) Division of Bellevue Hospital. As in the study of normal subjects referred to 3 the electrocardiograms taken in each case were the 3 standard leads, the potentials of the 3 extremities, and the potentials of 6 precordial points. All electrocardiograms were taken with a single stage, vacuum tube amplifier in circuit with the string galvanometer. This amplifier was designed and constructed by Dr. Franklin D. Johnston of the University of Michigan Medical School, to whom the author takes this opportunity to express his sincere appreciation. In about one-third of the cases the curves were taken simultaneously with standard lead I.

To date 183 patients have been studied. They include cases with left or right deviation of the electrical axis with or without cardiac hypertrophy; discordant and concordant left bundle branch block; typical and atypical right bundle branch block; intraventricular block; acute rheumatic myocarditis; acute fibrinous pericarditis; one case each of pericarditis with effusion and dextrocardia; and 45 cases of fresh or old infarction of the myocardium.