Canonical: https://echosuite.app/guides/mpap-rvot/

# Mean pulmonary artery pressure calculator: RVOT acceleration time

Find the RVOT acceleration-time method for mean pulmonary artery pressure, with its acquisition guidance and reference context.

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

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

## Method

mPAP = 79 − 0.45 × RVOT AcT; if AcT <120 ms, also 90 − 0.62 × AcT

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

### RVOT acceleration time  ms

PW Doppler just below the pulmonary valve

- From the PA-bifurcation PSAX view, place a 1–2 mm PW sample in the distal RVOT just beneath the pulmonary valve.
- Optimize scale, baseline, wall filter, and beam alignment so the entire systolic envelope is visible.
- Trace the modal envelope for VTI; measure acceleration time from flow onset to peak velocity and interpret cautiously when heart rate is <60 or >100 bpm.

### Heart rate  bpm

Spectral Doppler timing

- Use a sweep speed that clearly shows the interval boundaries.
- Measure from the specified onset to offset.
- Average representative beats using consistent rhythm handling.

## Sources and method context

American Society of Echocardiography · 2025 · Guidelines for the Echocardiographic Assessment of the Right Heart in Adults and Special Considerations in Pulmonary Hypertension · Table 1 JASE p. 145 · RVOT AcT pp. 158–159 · Table 4 / mPAP p. 166

[Primary reference](https://www.asecho.org/wp-content/uploads/2026/08/ASE-Right-Heart-Guidelines-May-2025.pdf)

- Acquisition and heart-rate limitation · RVOT VTI and AcT · JASE pp. 158–159

Distal RVOT sample placement, onset-to-peak timing, >105-ms normal reference, and reduced reliability below 60 or above 100 bpm.

- Empirical equations · Table 4 · JASE pp. 161–163; mPAP p. 166

The 79−0.45×AccT equation and the alternate 90−0.62×AccT equation when AccT is below 120 ms.

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

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