An electronic frequency shifting stethoscope for heart sounds.

Abstract

The predominating energy in the normal heart sounds has been found to be at frequencies below the normal hearing threshold. Because it was felt that significant clinical information was likely to be present at those frequencies, an instrument was designed and fabricated which would frequency shift the entire heart sound into the middle of the auditory frequency range. Clinical testing showed that changes were readily detected in a monitoring situation, and that use of the instrument was both simple and easy to learn.