In 42 patients with congenital or acquired heart disease, we have recorded the heart sounds before and after operation together with direct auscultation of the heart exposed at operation. This was done to clarify certain poorly understood aspects of cardiac murmurs, such as their persistence after apparently adequate repair of the underlying defect. Our experience has provided some practical guides in surgical treatment of cardiac lesions.
Studies at operation involved the application of a sterile, special microphone to parts of the heart and great vessels before and after operative treatment of the lesion. These operative studies were compared with the preoperative findings and with those recorded after about a week when the chest dressings had been removed.Heart sound recordings were made simultaneously on the Sanborn Twin-Beam and on the Cambridge heart sound magnetic tape recorder with oscilloscopic projection. Before entering the surgical field, the examiner was equipped with