1. What is Stroke Volume?

Stroke Volume (SV) is the volume of blood pumped from the left ventricle per beat. It is an important hemodynamic parameter measured in echocardiography to assess cardiac function.

2. How Does the Calculator Work?

The calculator uses the Stroke Volume formula:

Where:

• \( LVOT Diameter \) — Left Ventricular Outflow Tract diameter (cm)
• \( VTI \) — Velocity Time Integral (cm)
• \( 0.785 \) — Constant representing π/4

Explanation: The formula calculates the cross-sectional area of the LVOT (πr²) multiplied by the VTI to determine the volume of blood ejected per heartbeat.

3. Importance of Stroke Volume Calculation

Details: Stroke volume measurement is crucial for assessing cardiac output, evaluating ventricular function, and monitoring patients with heart failure or valvular heart disease.

4. Using the Calculator

Tips: Enter LVOT Diameter in centimeters, VTI in centimeters. Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal range for stroke volume?
A: Normal stroke volume ranges from 50-100 mL per beat in healthy adults at rest.

Q2: How is VTI measured in echocardiography?
A: VTI is measured using pulsed-wave Doppler at the LVOT, tracing the spectral Doppler envelope to calculate the velocity-time integral.

Q3: Why is 0.785 used in the formula?
A: 0.785 represents π/4, which is used to calculate the cross-sectional area from the diameter measurement (Area = πr² = π(d/2)² = πd²/4).

Q4: What factors can affect stroke volume?
A: Preload, afterload, contractility, heart rate, and valvular function can all influence stroke volume measurements.

Q5: How does stroke volume relate to cardiac output?
A: Cardiac output = Stroke Volume × Heart Rate, making SV a fundamental component of overall cardiac performance assessment.