Calculate aortic or mitral valve area with the Gorlin formula from cardiac output, mean gradient and ejection or filling time.
Result
How to use this tool
Aortic uses the systolic ejection period and constant 44.3; mitral uses the diastolic filling period and 37.7.
In mL/min, or L/min using the advanced unit option.
Mean gradient in mmHg, heart rate in beats per minute, and the period in seconds per beat.
Below 1.0 cm2 severe, 1.0-1.5 moderate, above 1.5 mild.
Formula & worked example
Aortic valve: cardiac output 5000 mL/min, ejection period 0.33 s, heart rate 70 and gradient 40 mmHg give 5000 / (0.33 x 70 x 44.3 x sqrt(40)) = 0.77 cm2, severe stenosis.
Limitations — read this before you rely on it
Educational use only. This tool is for education only and is not medical advice. Talk to a clinician about any result that worries you, and never change treatment because of a calculator result.
Frequently asked questions
A hydraulic formula that derives valve area from flow (cardiac output), the time the valve is open, and the pressure drop across it, used in cardiac catheterisation.
44.3 for the aortic valve and 37.7 for the mitral valve reflect the different discharge coefficients and units of the two valves.
Below 1.0 cm2 is severe, 1.0-1.5 moderate and above 1.5 mild, alongside gradient and velocity criteria.
Valve area is approximately cardiac output (L/min) divided by the square root of the mean gradient, a bedside shortcut to Gorlin.
No. Grading also uses peak velocity, mean gradient, dimensionless index, symptoms and left ventricular function.