A 4-YEAR FOLLOW-UP OF MITRAL BIOPROSTHESES BY FAST FOURIER-TRANSFORM MONITORING OF THE FIRST HEART-SOUND

The first heart sound of 21 patients with mitral prostheses showing no morphofunctional alterations at the echo and Doppler exams was analyz ed with the fast Fourier transform. The frequency peak related to the vibrations of the prosthetic valve was isolated and then was employed to compute an index of stiffness (E) of the bioprosthetic valve. In a previous study a good correlation between E and the duration of implan tation of the graft was found (r = 0.909, p < 0.0001). In this study t he value of E calculated again after 4 years in 10 patients was within the range expected for each patient's duration of implantation. The r esults suggest the reliability of the procedure employed for the monit oring of the regular aging process of the bioprosthetic valves and its usefulness as a complementary technique in the follow-up of patients with valvular bioprostheses.