ECHONOMY Tools for Echocardiographic Calculations Muhamed Saric, MD, PhD
New York University
Purpose
To
calculate mitral valve area using the continuity principle which states that
the stroke volume that passes through the mitral valve in diastole is equal to the
stroke volume passing through the LVOT in systole.
Technical Hints
The method is not valid when there
is significant mitral or aortic regurgitation.
Calculator
LVOT Diameter (d):
cm
LVOT VTI
(by pulsed Doppler):
cm
Mitral valve VTI
(by continuous Doppler):
cm
Answers
LVOT Area:
cm2
Mitral Valve Area (MVA):
cm2
Formulas
LVOT Area = (1/2 * d)2
* pi
MVA = LVOT Area * (LVOT VTI / MV VTI)
Reference
Holen J, Aaslid R, Landmark K,
Simonsen S, Ostrem T. Determination of effective orifice area in mitral
stenosis from non-invasive ultrasound Doppler data and mitral flow rate.
Acta Med Scand 1977;201:83-88.
Karp K, Teien D, Eriksson P.
Doppler echocardiographic assessment of the valve area in patients with
atrioventricular valve stenosis by application of the continuity equation.
J Intern Med 1989;225:261 266.