Stein P D
Angiology. 1982 Jun;33(6):401-9. doi: 10.1177/000331978203300606.
New information related to the mechanism of heart sound and murmurs, and a more detailed understanding of some aspects of cardiac function, permit a more complete and accurate interpretation of auscultatory signs in patients with ischemic heart disease. The diminished second sound in such patients is now recognized to reflect isovolumic relaxation, and the diminished first sound probably reflects impaired isovolumic contraction. Ejection murmurs can be interpreted in light of their relation to turbulent flow. The variability of regurgitant murmurs in the papillary muscle dysfunction syndrome seems to be explained by new observations related to the function of the papillary muscle.