Intracardiac Phonocardiography in Man

Abstract
This paper describes a new method for the detection of sound from within the heart in man. It employs the technic and equipment of underwater listening developed and used by the Navy in antisubmarine warfare. Records are shown to illustrate the localization of heart sound production to an extent not possible by phonocardiograms from the chest wall. The technic has proved helpful in the evaluation of patients with valvular and congenital heart disease.