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Left Ventricular Outflow Tract Velocity-Time Integral (Systolic)

Published: August 9, 2026Updated: August 16, 2026

This test measures the velocity of blood flow through the left ventricular outflow tract during the systolic phase of your heartbeat, often used in echocardiograms to assess heart function.

Quick summary

["Helps evaluate how well your heart pumps blood out of the left ventricle during each heartbeat."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
80029-2
Short code
LVOT Vmax sys
Synonyms
LVOT Vmax sys
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-doppler
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

The test focuses on the velocity of blood flow through the left ventricular outflow tract (LVOT), which is the passage through which blood exits the left ventricle into the aorta. During systole (when the heart muscle contracts), blood flows from the left ventricle through the LVOT. The velocity-time integral (VTI) quantifies this flow over time, providing insight into the efficiency of blood ejection from the heart.

Why It’s Done

Doctors may order this test to diagnose or monitor conditions affecting heart function, such as hypertrophic cardiomyopathy, aortic stenosis, or other structural heart abnormalities. It can also help evaluate the effectiveness of treatments for heart conditions.

Common Uses

This measurement is frequently used in echocardiograms to assess cardiac output, detect abnormal blood flow patterns, and guide decisions about medical or surgical interventions.

How the Test Works

The test is typically performed using echocardiography, a non-invasive ultrasound technique. A transducer is placed on your chest to capture images of your heart. The velocity of blood flow through the LVOT is measured during systole, and the VTI is calculated to provide a numerical value.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

LVOT Velocity-Time Integral (Systolic)

Frequently asked questions

How might this test result affect my treatment plan?
A lower-than-expected VTI may indicate reduced blood flow or impaired heart function, while an abnormally high value could suggest conditions like aortic stenosis or other structural issues. Your healthcare provider will interpret the results in the context of your overall health and symptoms to guide further care.
What does a low or high VTI mean?
While specific reference ranges aren’t provided here, abnormal VTI values may signal underlying heart problems. Your doctor will compare the result to your clinical picture and other diagnostic findings to determine next steps, such as additional testing or treatment adjustments.
Can this test be done without an echocardiogram?
This specific measurement is almost always performed during an echocardiogram, as it relies on ultrasound imaging to visualize blood flow through the heart. Other indirect assessments of heart function may exist, but they won’t provide the same detailed VTI data.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy