Electrocardiographic Study of Movements of the Heart with Change of Posture.

Abstract

The human electrocardiogram, as recorded, leading off from points on the surface of the body, is influenced by extracardiac factors, particularly by the effects of the tissues about the heart and the relation of the heart to the surrounding tissues. It is possible for a variation in the electrocardiogram to occur by a change in the extracardiac relations, even though the processes within the heart remain unaltered. Several observers have noted a variation in the form of the electrocardiogram on change of position of the body from the reclining to the lateral positions. There is no agreement as to the type and degree of the alterations nor as to the mechanism underlying these changes. The previous observations have been limited to a small group of subjects and no analysis of a sufficiently large number exists to justify definite conclusions.

In the present study, electrocardiograms were made of 60 individuals in 3 positions, in the reclining, in the left lateral and right lateral positions. The material consisted of normal subjects and of cardiac patients in whom a fixed heart was improbable, such as cases of hypertension heart and coronary disease. The latter were included to determine the effect of cardiac enlargement. The influence of such factors as habitus of the individual, size and displacement of the heart, was noted. Of the 60 cases, 55, or 91%, presented some definite electrocardiographic alteration on change of position of the body.