ESTIMATION OF PULMONARY-ARTERY PRESSURE BY SPECTRAL-ANALYSIS OF THE 2ND HEART-SOUND

The objective of the present work was to test and validate a noninvasi ve method based on spectral analysis of the second heart sound (S2) to estimate the pulmonary artery (PA) systolic pressure in 89 patients w ith a bioprosthetic heart valve, The technique was compared with conti nuous-wave Doppler estimation of PA systolic pressure in these patient s, The heart sounds recorded at the pulmonary area on the chest wall w ere digitized by computer, The spectra of S2 and those of the aortic ( A2) and the pulmonary (P2) components of S2 were computed with a fast- fourier transform, Seven features were extracted from these spectra. T he statistical analysis performed with the Pearson linear correlation coefficient showed that the best estimation of PA systolic pressure ob tained by spectral phonocardiography (r = 0.84, SEE +/- 5.6 mm Hg, p < 0.0001) was provided by the following equation: PA systolic pressure = 47 + 0.68 Fp - 4.4 Qp - 17 Fp/Fa - 0.15 Fs, where Fs and Fp are domi nant frequencies associated with the maximal amplitude of the power sp ectra of S2 and P2, respectively, Qp is the quality of resonance of P2 , and Fp/Fa is the ratio of the dominant frequencies of P2 and A2, res pectively.