1. What is LVOT VTI?

LVOT VTI (Left Ventricular Outflow Tract Velocity Time Integral) is an echocardiographic measurement that represents the distance blood travels during one cardiac cycle. It's calculated by integrating the velocity of blood flow over time in the left ventricular outflow tract.

2. How Does the Calculator Work?

The calculator uses a simplified formula:

Where:

• Peak Velocity — Maximum blood flow velocity (m/s)
• Ejection Time — Duration of systolic ejection (s)

Explanation: This formula provides an approximation of the VTI, which is typically measured by tracing the velocity-time curve on echocardiography.

3. Importance of LVOT VTI Measurement

Details: LVOT VTI is crucial for calculating stroke volume and cardiac output. It's used in assessing ventricular function, valve disorders, and hemodynamic status in various cardiac conditions.

4. Using the Calculator

Tips: Enter peak velocity in m/s and ejection time in seconds. These values are typically obtained from pulsed-wave Doppler echocardiography of the LVOT.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal LVOT VTI value?
A: Normal LVOT VTI typically ranges between 18-22 cm in healthy adults, though it can vary based on age, heart rate, and hemodynamic status.

Q2: How is LVOT VTI measured on echo?
A: It's measured by placing pulsed-wave Doppler sample volume in the LVOT just apical to the aortic valve and tracing the outer envelope of the spectral Doppler signal.

Q3: Can LVOT VTI change with heart rate?
A: Yes, VTI may decrease with tachycardia as ejection time shortens, though velocity may increase to maintain cardiac output.

Q4: What affects LVOT VTI accuracy?
A: Proper Doppler alignment, sample volume placement, and accurate tracing are crucial. Signal quality and patient factors like arrhythmias can affect accuracy.

Q5: How is VTI used in clinical practice?
A: VTI is used to calculate stroke volume (SV = VTI × LVOT area), cardiac output, and to assess response to therapies in heart failure and shock.