Abstract
We studied the closing sound of SJM prosthetic heart valve(SJM) by the power-frequency-time analysis, using the fast Fourier transform; the method of Wigner-Ville. The peak of distribution of power-frequencytime surface was around 1.3 to 1.5KHz, and its maximal value was up to 5.0 KHz. As the frequency of the sound spectrum became higher, the power became weaker proportionally . By the pseudo-thrombus attachment to the SJM ring, decrease in the power was noted especially in the range of 1.5 to 3.0 KHz. When the size of the pseudo-thrombus was gotten to be bigger, decrease in the power in the range of 1.5 to 3.0 KHz was also noted. Furthermore, the appearance-time of the sound spectrum got shorter. When it was the maximal size of pseudo-thrombus, finally, the distribution of the continuous frequency peaked at 1.0 KHz was only noted. In this study, by analysis of the power-frequency-time analysis of the closing sound of SJM, the decrease in the power as well as shortening o f the appearance-time of the spectrum were noted in the case of the pseudo-thrombus attached on SJM. It was soncluded that the powerfrequency-time analysis of closing sound of SJM was useful for the early and accurate diagnosis for its malfunction.
