Parameters:
(1) body surface area in square meters
(2) left atrial end-systolic volume in mL
(3) left atrial end diastolic volume in mL
(4) velocity time integral of the left ventricular outflow tract in cm
left atrial emptying fraction =
= ((left atrial end systolic volume) – (left atrial end diastolic volume)) / (left atrial end systolic volume)
left atrial end systolic volume indexed to BSA in mL per square meter =
= (LAESV) / (BSA)
left atrial function index = LAFI
= ((left atrial emptying fraction) * (velocity time integral) / (LAESV indexed to BSA)
LAFI is expressed in “units” or cm/cc/(square meter).
Normal controls had an LAFI from 0.37 to 0.71.
Patients with chronic atrial fibrillation had LAFI from 0.05 to 0.15.
