Thomas et al reported the left atrial function index (LAFI) which is a rhythm independent measure of left atrial function. The authors are from University of Sydney, Westmead Hospital, and Univrsity of California San Francisco.



(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.


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