LVOT VTI
Pronunciation: V-T-I
Left ventricular outflow tract velocity-time integral, used to calculate stroke volume and cardiac output.
Full Definition
Left ventricular outflow tract velocity-time integral represents the area under the velocity curve obtained by pulsed-wave Doppler at the LVOT level. VTI is measured by tracing the velocity envelope of the LVOT flow profile throughout systole. Combined with the LVOT diameter measurement, VTI allows calculation of stroke volume using the formula: SV = VTI × π × (LVOT diameter/2)². This measurement is fundamental for assessing cardiac output, valve areas (using the continuity equation), and hemodynamic status. LVOT VTI is particularly useful in monitoring cardiac performance and calculating effective orifice areas in valvular disease.
Usage
Usage note: Report in centimeters; ensure proper sample volume placement just proximal to aortic valve for accuracy.
In Context
- "LVOT VTI was reduced at 15 cm, consistent with low cardiac output state." — Heart failure assessment
- "Stroke volume was calculated using LVOT diameter and VTI measurements." — Hemodynamic evaluation