A Study of Heart Sounds and Murmurs by Direct Heart Recordings

Abstract

A method is described for recording heart sounds and murmurs on the surface of the heart chambers and great vessels. Studies were performed on normal dogs and in those with murmurs of known origin, chiefly pulmonic and aortic stenosis. In addition, the reappearance of the murmurs in such cases was studied, following the release of caval occlusion. It was found that the systolic murmur of pulmonic stenosis returned almost immediately after release of caval occlusion, whereas the aortic murmurs did not return until usually from six to 10 beats after release. This may provide a basis for the differentiation of right heart and left heart murmurs by a carefully controlled Valsalva maneuver.