PHONOCARDIOGRAPHIC DIFFERENTIATION OF THE MURMUR OF MITRAL INSUFFICIENCY FROM SOME COMMONLY HEARD ADVENTITIOUS SOUNDS IN CHILDHOOD

Abstract

Phonocardiographic tracings were recorded in children with known insufficiency of the mitral valve, children with a variety of systolic murmurs without blowing quality and children with no audible cardiac murmurs. The murmurs of valvular insufficiency produced tracings with a completely patternless and disorganized wave form. The other nonblowing murmurs all yielded tracings of uniform sine-wave character, regardless of their acoustic quality. Of these, the majority were "twanging-string" murmurs, the loudest of these with a distinct buzzing quality; the others were "snorting," "scraping" or "grating" in quality. Clinical observations indicated that these nonblowing murmurs were not indicative of cardiac disease. The murmurs of mitral insufficiency were significantly longer than the nonpathologic murmurs, but the latter showed, on the average, fully as great amplitude on the tracings. Physical and clinical implications of these findings are discussed.