Doppler Echo Cardiac Output Calculator
Calculate cardiac output, cardiac index, and stroke volume using Doppler echocardiography LVOT measurements. Instant results with normal range indicators and charts.
About This Calculator
The Doppler Echo Cardiac Output Calculator is a specialized tool for healthcare professionals and medical students to compute cardiac output (CO), cardiac index (CI), and stroke volume using measurements obtained from Doppler echocardiography. It uses the left ventricular outflow tract (LVOT) diameter and velocity time integral (VTI) along with patient height, weight, and heart rate to derive key hemodynamic parameters.
The calculator applies the standard Doppler echo formula: cross-sectional area (CSA) of the LVOT is calculated as π × (LVOT diameter/2)², representing the circular area of the outflow tract. Stroke volume is then computed as CSA multiplied by LVOT VTI (the stroke distance). Finally, cardiac output is obtained by multiplying stroke volume by heart rate and dividing by 1000 to convert mL to L/min. Body surface area is computed using the Mosteller formula: √(height × weight / 3600), which is used to calculate cardiac index (CO/BSA).
Regional Notes
United States (US): LVOT diameter is often reported in mm clinically (normal 18–22 mm). Enter as cm (divide mm by 10). Height is entered in cm and weight in kg. Normal cardiac output is 4–8 L/min and cardiac index 2.5–4.0 L/min/m² per American Society of Echocardiography guidelines.
United Kingdom (UK): UK clinical practice follows the same ASE guidelines for Doppler echo measurements. Height and weight are measured in metric units. The British Society of Echocardiography recommends VTI >18 cm as normal. Cardiac index of 2.5–4.0 L/min/m² is the accepted reference range.
India: Indian echocardiography laboratories follow the same Doppler echo protocols. Normal LVOT diameter ranges from 1.8–2.2 cm in Indian adults. The Mosteller BSA formula is widely used in Indian clinical practice for cardiac output calculations.
Frequently Asked Questions
What is cardiac output?
Cardiac output (CO) is the volume of blood the heart pumps per minute. It is calculated by multiplying stroke volume by heart rate. Normal cardiac output ranges from 4 to 8 liters per minute in healthy adults.
How is cardiac output calculated with Doppler echo?
Doppler echo cardiac output is calculated using LVOT diameter and LVOT VTI measured via echocardiography. CSA is computed as π × (LVOT diameter/2)², stroke volume as CSA × LVOT VTI, and cardiac output as stroke volume × heart rate / 1000.
What is LVOT in echocardiography?
LVOT stands for Left Ventricular Outflow Tract, the cylindrical region of the left ventricle leading to the aorta. Its diameter and velocity time integral (VTI) are measured using Doppler echocardiography to compute stroke volume and cardiac output.
What is the difference between cardiac output and cardiac index?
Cardiac index (CI) is cardiac output divided by body surface area (BSA). While CO measures absolute blood flow, CI normalizes it for body size, allowing comparison between patients of different sizes. Normal CI is 2.5–4.0 L/min/m².
What is a normal LVOT diameter?
Normal LVOT diameter ranges from 18 to 22 mm (1.8 to 2.2 cm) in adults. The LVOT cross-sectional area (CSA) is derived from this diameter using the circle area formula and typically ranges from 2.5 to 3.8 cm².
What is LVOT VTI and what are normal values?
LVOT VTI (Velocity Time Integral) represents the distance blood travels through the LVOT during systole, measured in cm via pulsed-wave Doppler. A normal LVOT VTI is greater than 18 cm, with values below this suggesting reduced stroke volume.
Is the Doppler echo cardiac output calculator free?
Yes, this Doppler echo cardiac output calculator is completely free to use with no registration required. It provides instant results with charts and breakdown tables for clinical reference.
Can this calculator be used for all patient populations?
The Doppler echo cardiac output calculator uses standardized formulas (Mosteller BSA, circular CSA) suitable for adults. For pediatric patients, alternative BSA formulas may be more appropriate. Always consult a physician for clinical decisions.