Canonical: https://echosuite.app/guides/rv-function-calc/

# Right ventricular function calculator: TAPSE, FAC and coupling

Explore the RV function and coupling measurements available in the tool, with acquisition teaching and method-specific references.

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

[Open interactive calculator →](https://echosuite.app/calculators/#rv-function-calc)

## Method

FAC or EF = (end-diastolic − end-systolic) ÷ end-diastolic × 100; coupling = TAPSE ÷ PASP

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

### Measurement

Enter the measured value in the displayed unit

- TAPSE
- S′
- FAC
- Free-wall strain
- 3D RVEF
- TAPSE/PASP
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### TAPSE  mm

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.

### Lateral tricuspid S′  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.

### End-diastolic area  cm²

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.

### End-systolic area  cm²

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.

### Free-wall strain · magnitude  %

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.

### 3D end-diastolic volume  mL

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.

### 3D end-systolic volume  mL

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.

### Estimated PASP  mmHg

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.

### PASP acquisition

Enter the measured value in the displayed unit

- Reliable
- Unreliable / uncertain
- 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

ASE · 2025 · Echocardiographic Assessment of the Right Heart in Adults · Table 1; RV size pp.143–151; function pp.156–160; TAPSE/PASP pp.156–157

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

- Acquisition and interpretation · Table 1; RV size pp.143–151; function pp.156–160; TAPSE/PASP pp.156–157

Method-specific acquisition and reference context. Arithmetic uses entered measurements; clinical interpretation remains subject to image quality and study context.

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

- [Apical four chamber acquisition guide](https://echosuite.app/guides/views/apical-four-chamber/) · [Open in Probe Lab](https://echosuite.app/#a4c)
- [Right atrial pressure assessment: IVC and hepatic vein flow](https://echosuite.app/guides/rap/)
- [Right atrial size calculator and measurement guide](https://echosuite.app/guides/ra-size/)
- [Right ventricular size calculator and measurement guide](https://echosuite.app/guides/rv-size-calc/)
- [RVSP and PASP calculator: tricuspid regurgitation velocity](https://echosuite.app/guides/rvsp/)
- [Right-heart echocardiography: views, measurements and calculators](https://echosuite.app/learn/right-heart-echo/)

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