About the mitral valve area calculator
Mitral valve area (MVA) is a measurement of how open the mitral valve orifice is during diastole, used to grade the severity of mitral stenosis. This calculator applies the Gorlin formula, the standard hemodynamic equation for computing valve area from flow and pressure gradient data, whether the inputs come from cardiac catheterization or Doppler echocardiography.
How the Gorlin formula works
- Diastolic transvalvular flow rate (mL/sec) is cardiac output (mL/min) divided by the diastolic filling period (seconds per beat) times heart rate (beats per minute) — this is the average rate blood crosses the valve while it is open.
- Mitral valve area (cm2) equals that flow rate divided by 37.7 times the square root of the mean transmitral pressure gradient (mmHg). The constant 37.7 is the empirical mitral-valve correction of the original Gorlin flow coefficient.
- Small errors in the diastolic filling period or the mean gradient have an outsized effect on the result because the gradient enters under a square root and the filling period is in the denominator — measure these carefully.
Putting the result in context
Compare the calculated area against standard severity bands: roughly 4-6 cm2 is normal, above 1.5 cm2 is generally mild, 1.0-1.5 cm2 is moderate, and 1.0 cm2 or below is severe mitral stenosis. These are population-based reference cutoffs used in echocardiography guidelines, not a diagnosis for any one patient — planimetry and clinical assessment should corroborate the hemodynamic estimate.
When to consult a professional
This tool performs the standard Gorlin arithmetic for education and record-keeping. It is not a diagnosis and does not direct treatment. Any decision about intervention should rest with a cardiologist, who interprets the valve area alongside symptoms, imaging, and the full clinical picture.