Atrial septal defect: shunt and Doppler calculator

Explore the atrial septal defect tool’s anatomy, shunt and Doppler teaching, with the measurements and sources for its available methods.

Created by Mohammed Kamareddine, MD · Sources & educational scope

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Method

Qp/Qs = (Dpulmonary² × VTIpulmonary) / (DLVOT² × VTILVOT); atrial mean ΔP is directly traced

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

Clinical question

Enter the measured value in the displayed unit

Shunt flow · Qp/Qs
Atrial Doppler mean

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

RVOT diameter at the PW sample 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.

RVOT 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.

LVOT diameter at the PW sample 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.

Atrial physiology

Enter the measured value in the displayed unit

Not established
Isolated ASD
Complex CHD / atrial egress

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

Traced atrial mean gradient mmHg

Complete traced CW envelope

Align through the valve or shunt and record a complete envelope.
Trace the modal velocity envelope using the machine tool.
Use the machine-calculated mean gradient in mmHg.

Sources and method context

ASE / SCAI · ACC / AHA · 2026 · ASD anatomy, Doppler flow and integrated assessment · ASE/SCAI 2015 pp. 912–916, 924–930, 932–935 · ASE pediatric TTE 2024 p. 142 · ACC pediatric guidance 2026

Primary reference

Anatomy and acquisition · Silvestry et al. JASE 2015;28:910–958 · pp. 912–916, 924–930 · doi:10.1016/j.echo.2015.05.015
Defect morphology, surrounding structures and outflow stroke-volume ratio. Subcostal orthogonal imaging helps avoid apical dropout; significant semilunar regurgitation limits flow estimation.
Current pediatric imaging · Lopez et al. JASE 2024;37:119–170 · p. 142 · doi:10.1016/j.echo.2023.11.015
Subcostal/right parasternal septal imaging, full-cycle PW direction, orthogonal size/rims and relationships to veins and AV valves.
Context for the 1.5 reference · 2025 ACHD guideline §4.1.1 · doi:10.1016/j.jacc.2025.09.006; 2026 ACC pediatric shunt guidance · doi:10.1016/j.jacc.2025.11.020
Shunt ratio is interpreted with right-heart enlargement and population-specific hemodynamics. This tool does not implement closure eligibility or a PVR estimate.
Restriction is lesion-specific · Atrial septal defect morphology and stenting in HLHS after hybrid palliation, 2017 · PMID 28889828
A selected HLHS cohort combined Doppler gradient and clinical signs. It does not validate universal mild/moderate/severe bands for all ASDs; none are applied 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

All echo guides · Learning paths