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
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.
This activity has been planned and implemented in accordance with the accreditation requirements and policies of the Accreditation Council for Continuing Medical Education through the joint providership of University of Nebraska Medical Center, Center for Continuing Education and JLS Interactive, LLC.
The University of Nebraska Medical Center, Center for Continuing Education is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.
This activity is approved by the American Society of Radiologic Technologists (ASRT) as sonography-related continuing education (CE). Credit(s) issued for successful completion of ASRT-approved CE activities are accepted by the American Registry of Diagnostic Medical Sonography, American Registry of Radiological Technologists, Cardiovascular Credentialing International and Canadian Association of Registered Diagnostic Ultrasound Professionals. Contact the applicable registry for additional information / restrictions on their acceptance of ASRT CE credit.