[Contoursonagraphic analysis of heart sound phenomena and sounds produced by various heart valve prostheses].

The normal heart sounds, murmurs, opening and closing sounds of aortic and mitral valve prostheses were recorded on a tape and analyzed in terms of contour sonagrams in order to obtain the highest frequencies which were recordable on the chest wall. The peak frequencies showed a broad range, the maximum beeing reached at about 8000 c.p.s. in the case of the sounds of prosthetic valves. Furthermore, sound level examinations of the normal first and second heart sound, as well as of the opening and closing sounds of the aortic valve prostheses were performed. The highest sound level of all of these sounds was found to lie within the low frequency range of 40 to 100 c.p.s.