Canonical: https://echosuite.app/guides/lvot-respiratory/

# LVOT · respiratory variation calculator

Explore lvot · respiratory variation with the method’s inputs, acquisition guidance and source references. Open the calculator to enter measurements or try an illustrative worked example.

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

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

## Method

Inspiratory fall = (expiratory value − inspiratory value) / expiratory value × 100

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 measurement

Enter the measured value in the displayed unit

- Peak velocity
- VTI
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Expiratory peak Vₑ  cm/s

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Inspiratory peak Vᵢ  cm/s

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Expiratory VTIₑ  cm

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Inspiratory VTIᵢ  cm

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

## Sources and method context

American Society of Echocardiography · 2013 · Clinical Recommendations for Multimodality Cardiovascular Imaging of Patients with Pericardial Disease · Figure 38, journal p. 990; Doppler flow recordings pp. 988–991

[Primary reference](https://www.asecho.org/wp-content/uploads/2025/04/2013_Multimodality-CV-Imaging-for-Pericardial-Disease.pdf)

- Method and interpretation · Figure 38, journal p. 990; Doppler flow recordings pp. 988–991

Inspiratory LVOT velocity reduction and respiratory changes in ejection; no standalone numerical cutoff is assigned here.

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

- [Pericardial effusion size measurement guide and calculator](https://echosuite.app/guides/effusion-size/)
- [Mitral inflow · respiratory variation calculator](https://echosuite.app/guides/mitral-respiratory/)
- [Tricuspid inflow · respiratory variation calculator](https://echosuite.app/guides/tricuspid-respiratory/)
- [Hepatic vein · expiratory reversal calculator](https://echosuite.app/guides/hepatic-expiratory-reversal/)

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