The first derivative of systolic Doppler flow: methods and clinical applications

The clinical usefulness of the first derivative of systolic Doppler flow was studied in 33 patients with coronary artery disease. The digitized frames were processed by filtering, smoothing, and determining the boundary contour. The first derivative was computed by polynomial interpolation, and some important deviation parameters were calculated. To study the importance of these measurements some invasive systolic parameters were estimated by multiple regression analysis with good results. The interrelation of invasive and non-invasive systolic parameters was studied by factor analysis