The flow velocity in the left ventricular outflow tract is typically 70-110 cm/s in adults and 70-120 cm/s in children.
The left ventricular outflow tract generally refers to the section of the left ventricular cavity from the apex to the aortic orifice, and its outlet is the aortic orifice. Measurement of this flow velocity is often used clinically to determine whether hypertrophic cardiomyopathy is characterized by the presence of outflow tract obstruction.
A significant increase in LV systolic flow velocity and an increase in the pressure difference are often indicative of outflow tract obstruction.
Abnormal outflow tract velocities should be considered in conjunction with the size of the heart, the thickness of the interventricular septum, and the ejection fraction and volume of the left ventricle, as well as the size of the valves to determine the presence of cardiac disease.