1. What is Stroke Volume?

Stroke Volume (SV) is the volume of blood pumped from the left ventricle per beat. It's a key parameter in assessing cardiac function and is calculated using LVOT diameter and Velocity Time Integral (VTI) from Doppler echocardiography.

2. How Does the Calculator Work?

The calculator uses the stroke volume equation:

Where:

• \( SV \) — Stroke volume (mL)
• \( LVOT\ diameter \) — Left ventricular outflow tract diameter (cm)
• \( VTI \) — Velocity time integral (cm)
• \( \pi \) — Mathematical constant pi (~3.1416)

Explanation: The equation calculates the cross-sectional area of the LVOT (πr²) and multiplies it by the distance blood travels in one beat (VTI).

3. Clinical Importance

Details: Stroke volume is essential for calculating cardiac output (CO = SV × HR). It helps assess ventricular function, valve disorders, and hemodynamic status.

4. Using the Calculator

Tips: Measure LVOT diameter in parasternal long-axis view during systole. VTI is obtained from pulsed-wave Doppler at the LVOT. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal stroke volume?
A: Normal SV ranges from 60-100 mL in adults, varying with body size and physiology.

Q2: How does this relate to ejection fraction?
A: EF = (SV/EDV) × 100, where EDV is end-diastolic volume. SV provides absolute volume while EF is a percentage.

Q3: What affects VTI measurements?
A: Proper Doppler alignment is crucial. Suboptimal angles (>20°) underestimate true velocity.

Q4: Why use LVOT diameter?
A: LVOT is typically circular and has laminar flow, making it ideal for flow calculations.

Q5: Can this be used for right ventricular SV?
A: Similar principles apply but using RVOT measurements. Right-sided calculations are often less accurate.