Enter measurement data
Calculation results
| Parameter | General range |
|---|---|
| Stroke volume | ± 50 – 100 mL |
| Cardiac output | ± 4 – 8 L/min |
| Cardiac index | ± 2.5 – 4.0 L/min/m² |
The ranges above are values commonly cited in the literature for resting adults and vary by population, method, and clinical condition. Interpretation remains with the physician/cardiologist.
Worked examples
Case A — typical resting values
LVOT diameter 2.0 cm · VTI 20 cm · HR 70 bpm · weight 70 kg · height 170 cm
Results: CSA 3.1416 cm² → SV 62.83 mL → CO 4.398 L/min → BSA 1.810 m² → CI 2.43 L/min/m².
Case B — low-number example (calculation illustration)
LVOT diameter 1.9 cm · VTI 14 cm · HR 58 bpm (no anthropometric data)
Results: CSA 2.8353 cm² → SV 39.69 mL → CO 2.302 L/min. Cardiac index not computed because weight/height were not entered.
Frequently asked questions (FAQ)
What is cardiac output (CO) in Doppler echocardiography?
Cardiac output is the volume of blood pumped by the left ventricle each minute (L/min). In Doppler echo: CO = SV × HR / 1000, with stroke volume SV = CSALVOT × VTI.
What is VTI in Doppler examination?
VTI (velocity-time integral) is the area under the pulsed-wave Doppler spectrum curve (cm) — the distance traveled by the blood column during one beat. For SV it is usually measured just below the aortic valve.
Why is the LVOT diameter measured rather than its area directly?
The LVOT is assumed circular: CSA = π × (diameter/2)². Beware: small errors in diameter are squared in the CSA, so measure as carefully as possible following the echo lab protocol.
What is the cardiac index (CI)?
CI = CO / BSA (L/min/m²) — cardiac output normalized to body surface area so it can be compared across body sizes. This calculator uses the Du Bois formula: BSA = 0.007184 × weight0.425 × height0.725.
Why does the calculator result differ from my echo report?
Possible causes: LVOT diameter measurement variability, rounding, geometry assumptions, Doppler angle, or echo-lab-specific corrections. Discuss your echo report with your treating physician/cardiologist.
Can this calculator be used for diagnosis?
No. This is an educational tool for understanding Doppler hemodynamic calculations. Clinical interpretation is always by a physician/cardiologist in a complete clinical context.
Scope boundary — what this tool does NOT compute
This tool only computes cardiac output from LVOT Doppler (CSA × VTI × HR, plus optional cardiac index). This tool does not compute: valve pressure gradients, aortic valve area (full continuity equation), PISA/regurgitation, diastolic function, or other echo parameters — and it is not a substitute for a complete echocardiography report.
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