|How to calculate a AVA by Gorlin Formula.|
|CO = 0.785 x LVOTd2 x VTIAV x HR AVG = 4(Vmean)2 AVA = (CO / SEP x HR) / (44.3 x sq root(AVG))|
|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.|
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.