title: [Color-Doppler study of the velocity profile of the left ventricular outflow tract in normal subjects and in patients with valvular aortic stenosis].
abstract: A better understanding of the velocity profiles in the cardiac chambers and great vessels should allow more accurate estimation of cardiac output and valve surface area by Doppler echocardiography. The velocity profile in the left ventricular outflow tract was studied by Colour Doppler in 12 patients with pure valvular aortic stenosis with normal left ventricular function and compared with a control population of 12 normal subjects. The selected recordings were digitised and stocked on a laser optic disc. Measurement of the angle of incidence of the line of colour aliasing with respect to the interventricular septum was performed manually on a colour video display unit. A program of digitised image processing allowed the tracing of the axes of reference defining the angle of incidence measured at peak systole. The average angle of incidence was 40.7 +/- 5.6 degrees in the control population and 56.8 +/- 6.8 degrees in aortic stenosis; therefore, in this condition, the angle was significantly flatter (less acute) (p less than 0.001). The correlation between the angle of incidence and the transvalvular pressure gradient was poor (r = 0.24). These results suggest that: real time ambulatory analysis of isovelocity profiles in the left ventricular outflow tract is possible by using the phenomenon of colour aliasing: the presence of an obstacle to left ventricular ejection tends to flatten the velocity profile, justifying the use of the continuity equation in patients with calcific aortic stenosis but questioning its systematic use in control populations of normal subjects used as a reference.
authors.affiliation: Service de réanimation médicale, hôpital Louis-Mourier, Colombes.
authors.forename: J P
authors.initials: JP
authors.lastname: Belot
authors.forename: C
authors.initials: C
authors.lastname: Scheublé
authors.forename: A
authors.initials: A
authors.lastname: Castillo-Fenoy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D006801:Humans; D008875:Middle Aged; D016249:Optical Storage Devices; D011446:Prospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left
vernacular_title: Etude du profil de vitesse de la chambre de chasse du ventricule gauche des patients normaux et atteints de rétrécissement orificiel aortique. Etude Doppler couleur.