Vibrations of Low Frequency over the Precordium

A method for taking tracings which represent actual movements of the precordium (displacement curves) or records which show waves proportional to the velocity of movement of the chest wall (velocity curves) is described. The equipment employed is readily available, and the method is easy to use. The displacement curves are nearly identical with cardiograms taken with a good optical setup, and they may have diagnostic value. The velocity curves are more closely related to the functional status of the myocardium. The clinical significance of these tracings, especially the former, is pointed out.