Value and limitations of Doppler echocardiographic determination of mitral valve area in Lutembacher syndrome.
OBJECTIVE
Our objective was to compare the Doppler pressure half-time, Doppler continuity equation and two-dimensional echocardiographic planimetric methods of estimating mitral valve area in Lutembacher syndrome.


BACKGROUND
Fluid dynamics theory predicts that mitral pressure half-time varies inversely with mitral valve area and directly with net chamber compliance and the peak early diastolic transmitral gradient in pure mitral stenosis. The effects of an atrial shunt on these interrelations have not been investigated.


METHODS
Correlation and agreement between mitral valve area estimates obtained by the three methods and that obtained by cardiac catheterization was ascertained in 11 patients with Lutembacher syndrome.


RESULTS
Valve areas determined by planimetry and the continuity equation method correlated and agreed well with catheterization measurements (r = 0.83 and 0.81, respectively). The pressure half-time method consistently overestimated mitral valve area; the extent of overestimation was greater in patients with larger atrial shunts. The hemodynamic pressure half-time was independent of the mitral valve area, chamber compliance and the peak transmitral gradient. It was dependent on the magnitude of the atrial shunt, although the correlation obtained was only fair (r = 0.61).


CONCLUSIONS
These findings suggest that the Doppler pressure half-time method is an inaccurate measure of mitral valve area whenever an atrial shunt coexists with mitral stenosis. Planimetry and the Doppler continuity equation methods yield accurate estimates of mitral valve area in Lutembacher syndrome.
Vasan
R S
RS
Department of Cardiology, All India Institute of Medical Sciences, New Delhi.
Shrivastava
S
S
Kumar
M V
MV
D000293:Adolescent; D000328:Adult; D006328:Cardiac Catheterization / Q000706:statistics & numerical data; D004452:Echocardiography / Q000706:statistics & numerical data; D015150:Echocardiography, Doppler / Q000706:statistics & numerical data; D005069:Evaluation Studies as Topic; D005260:Female; D006439:Hemodynamics; D006801:Humans; D016018:Least-Squares Analysis; D008185:Lutembacher Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D012044:Regression Analysis