A Quantitative Description of the Aortic Ejection Click and First Heart Sound

摘要

The aortic ejection click and first heart sound(S1) are described in the time and frequency domains from computer processed phonocardiogram data obtained from 13 aortic stenosis patients and 6 normal ones. The analysis procedure described was done separately for inspiration and expiration and consisted of the following steps: (1) determination of the click onset times; (2) generation of aligned average cardiocycles with alignment done separately on the click and S1; (3) calculation of power spectra for selected segments of the click and S1. Tabulated results typically show 2 frequencies in S1 (means at 40 and 75 Hz) and 3 in the click (means at 45, 95, and 195 Hz). The high frequency content of the click is compared to that of S1 and the power spectra of the early and late parts of the click are compared.