It is well known that biological heart valve substitutes are subjected to slower degeneration compared with metallic ones. Nevertheless degenerative phenomena, related to calcification, thrombus and fibrotic pannus deposition, are sometimes very fast and techniques for regularly monitoring patients with valve implants are needed. The acoustic analysis of heart sound produced by a bioprosthetic heart valve seems to be the most useful mean for recognising the degeneration when a valve is still functioning well and looks almost normal to echocardiography. In fact, the mechanical properties of a valve, namely stiffness, determine its vibrational behaviour and, consequently, influence its distinctive closing sound. In this work, a method for acoustic analysis of artificial valves sounds has been developed, which requires a phonocardiographic microphone, an acoustic tape recorder and an FFT board installed in a computer. With the FFT analyser it is possible to calculate the frequency spectrum of prosthesis sounds; this spectrum tends to change as tissue degeneration progresses. A series of 18 patients, 11 carriers of aortic bioprosthesis, 6 carriers of mitral bioprosthesis an 1 carrier of both mitral and aortic bioprostheses, has been observed during first five years after the implant: a first corroboration of introduced model and technique has been given.
Frequency analysis of phonocardiograms for recognition of degenerative phenomena in heart bioprostheses
ZANETTI, Elisabetta;
2002
Abstract
It is well known that biological heart valve substitutes are subjected to slower degeneration compared with metallic ones. Nevertheless degenerative phenomena, related to calcification, thrombus and fibrotic pannus deposition, are sometimes very fast and techniques for regularly monitoring patients with valve implants are needed. The acoustic analysis of heart sound produced by a bioprosthetic heart valve seems to be the most useful mean for recognising the degeneration when a valve is still functioning well and looks almost normal to echocardiography. In fact, the mechanical properties of a valve, namely stiffness, determine its vibrational behaviour and, consequently, influence its distinctive closing sound. In this work, a method for acoustic analysis of artificial valves sounds has been developed, which requires a phonocardiographic microphone, an acoustic tape recorder and an FFT board installed in a computer. With the FFT analyser it is possible to calculate the frequency spectrum of prosthesis sounds; this spectrum tends to change as tissue degeneration progresses. A series of 18 patients, 11 carriers of aortic bioprosthesis, 6 carriers of mitral bioprosthesis an 1 carrier of both mitral and aortic bioprostheses, has been observed during first five years after the implant: a first corroboration of introduced model and technique has been given.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
