Digital Fourier techniques in the diagnosis and quantification of aortic stenosis with pulsed-Doppler echocardiography.

Pulsed Doppler echocardiography and digital Fourier analysis were utilized to examine flow distal to the aortic valve and to quantify aortic stenosis. A graphic index of parameters derived from velocity spectrum patterns generated by Fourier analysis was regressed against mean systolic pressure gradients in 21 adults with clinical evidence of aortic stenosis who underwent catheterization studies and five normal adults (r = .82). Correlation improved in the absence of regurgitation (r = .92). Sensitivity for detecting gradients greater than 30 mmHg was 86%; specificity was 90%. Doppler spectral analysis shows promise in alleviating the need for many invasive studies.