THE MOTION OF THE THORAX DURING THE HEART CYCLE: A COMPARISON OF LONGITUDINAL, LATERAL AND DORSOVENTRAL BALLISTOCARDIOGRAMS 1

Abstract

The motion of a part of the body was imparted to a coil in a stationary magnetic field. The current generated is proportional to velocity of body motion but integrated by a 50 microfarad condenser across the leads gives wave forms for longitudinal motion similar to the displacement curve. Such devices applied to the shins and the thorax yield simultaneous curves of lateral and dorsoventral motion of the thorax during the heart cycle. Lateral traces show proportionately much more motion in diastole and, in cases of complete heart block, during auricular systole, than do the longitudinal traces. The lateral trace varies more in different phases of respiration. In myocardial disease with small featureless waves in longitudinal traces, the lateral trace had large and consistent patterns. Dorsoventral traces in right and left mid-clavicular lines indicate torsion of the thora. during systole. In 20 cases of congenital heart disease no correlation was noted between specific diagnoses and the patterns of lateral and longitudinal displacement.