Usefulness of a new sound spectral averaging technique to distinguish an innocent systolic murmur from that of aortic stenosis

We present a new method to record and display heart sounds that uses a hand-held computer and stethoscopic recording device. It allows for rapid spectral and waveform displays of murmurs and provides a means for signal averaging of spectral frequency content. Compared with aortic stenosis, innocent murmurs primarily contain frequencies of <300 Hz and persist for a shorter duration at the upper-frequency levels. This method provides for rapid characterization of innocent murmurs, a means for comparison with other murmurs, and transmission of acoustic data to distant sites.