Canonical: https://echosuite.app/guides/mitral-continuity/

# Mitral valve area calculator: continuity equation

Review the flow and mitral inflow measurements used by the continuity-equation tool for mitral valve area.

Created by [Mohammed Kamareddine, MD](https://echosuite.app/about/) · [Sources & educational scope](https://echosuite.app/about/)

[Open interactive calculator →](https://echosuite.app/calculators/#mitral-continuity)

## Method

MVA = LVOT area × LVOT VTI ÷ MV VTI

Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.

## Measurements and acquisition

### LVOT diameter  cm

2D echo · inner-edge measurement

- Use the specified view and cardiac phase.
- Align the calipers perpendicular to the structure’s long axis.
- Measure inner edge to inner edge and avoid oblique foreshortening.

### LVOT VTI  cm

Pulsed-wave Doppler

- Place the sample volume at the specified annulus or outflow tract.
- Align the Doppler beam with flow and record a clean envelope.
- Trace the modal velocity envelope and use the reported VTI.

### Mitral inflow VTI  cm

Continuous-wave Doppler trace

- Use the same aligned CW recording as the peak velocity.
- Trace the outer edge of the dense envelope for the relevant phase.
- Use the machine-reported VTI in centimeters.

## Sources and method context

American Society of Echocardiography · 2023 · Recommendations for the Use of Echocardiography in the Evaluation of Rheumatic Heart Disease · Continuity equation and exclusions p. 6 · alternative methods and recommendation p. 7 · Table 1 p. 6

[Primary reference](https://www.asecho.org/wp-content/uploads/2025/04/PIIS0894731722005211.pdf)

- Equation & paired acquisition · Continuity method · PDF p. 6

MVA from LVOT cross-sectional area times LVOT VTI divided by mitral VTI, with RVOT/pulmonic substitution when isolated AR is present.

- Method limitations · Continuity method · PDF pp. 6–7

Compounded measurement error, limited validation, infrequent use, and invalidity with important MR or AR when an appropriate competent reference is not used.

- Severity & clinical role · Table 1 p. 6 · alternative-method recommendation p. 7

Current MVA grades and use only as a corroborating method when planimetry, PHT, and mean gradient are inconclusive.

Catalogue review status: Exact guideline locator mapped · clinical sign-off pending

These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.

## Keep exploring

- [Parasternal long axis acquisition guide](https://echosuite.app/guides/views/plax/) · [Open in Probe Lab](https://echosuite.app/#plax)
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- [Mitral stenosis · PISA valve area calculator](https://echosuite.app/guides/mitral-pisa/)
- [Tricuspid stenosis · significance calculator](https://echosuite.app/guides/tricuspid-stenosis/)

[All echo guides](https://echosuite.app/guides/) · [Learning paths](https://echosuite.app/learn/)