EROA – Mitral Regurgitation Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Heart and vascular calculations often combine several measurements that are easy to misread in isolation. EROA – Mitral Regurgitation Calculator keeps those inputs together and shows the result the implemented model is designed to produce.

What this calculator does

EROA – Mitral Regurgitation Calculator uses Aliasing speed (Va), PISA radius (r), Maximal MR velocity (Vmax), and Mitral regurgitation VTI to calculate effective regurgitant orifice area and regurgitant volume. It is built around the exact fields displayed in this plugin rather than a generic version of the topic. Where supported, it also shows Regurgitant flow and Regurgitant volume so the primary result is easier to place in context. Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.

How to use it

Enter or select Aliasing speed (Va), PISA radius (r), Maximal MR velocity (Vmax), and Mitral regurgitation VTI. Use the units offered by the calculator and choose the option that matches the actual clinical or timing situation. Check date entries and laboratory units before relying on the output. When the formula combines measurements, use values obtained under the same assessment or physiologic conditions whenever possible.

How the calculation works

The PISA method is used. Regurgitant flow is 2πr² × aliasing velocity, effective regurgitant orifice area (EROA) is regurgitant flow divided by maximal mitral-regurgitation velocity, and regurgitant volume is EROA × MR velocity-time integral. The calculator keeps the entered velocities and distances in the units shown by the tool.

Example

Using the sample values prefilled in this calculator, the primary result is 0.377 cm² (Effective regurgitant orifice area), Regurgitant flow is 188.5 mL/s, and Regurgitant volume is 45.2 mL. This worked example shows how the plugin’s own default inputs flow through the implemented method; replace them with the correct patient, laboratory, imaging, or personal values before interpreting a result.

How to interpret the result

Read the output as effective regurgitant orifice area generated by this specific formula or score. The number is most useful when compared with the clinical context and, when appropriate, serial measurements or the current guideline pathway for the condition. A boundary value should not be overinterpreted as a sudden change in physiology.

Limitations and notes

Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.