Step 1: Obtain the LVOT Diameter.
The ME AVLAX view under zoomed mode is an excellent method
to measure the LVOT diameter. Measure the LVOT diameter
in mid systole.
Step 2: Obtain a
CWD of the AV. The optimal view is either
the DTG AVLAX or TG AVLAX. Once a flow profile is
obtained, trace the envelope to calculate the mean velocity
(Vmean) and the VTI. From the flow profile the SEP
or systolic ejection period can be measured.
Step 3: Enter the
Heart Rate.
Optional:
Modified Gorlin Formula:
AVA = CO / Square Root of Mean AVG.
The cardiac output is in liter per minute.
For example a CO of 5.4 l/min and a mean AVG of 64 yields
5.4 / sq root(64) = 0.68 cm squared.
