UPmémoires

Objectives: The aim of this study was to explore the left atrial appendage (LAA) anatomy and function in cardiac CT, in a large cohort with atrial fibrillation (AF), and compare them to « healthy » patients, in order to look for any predictive factor of thromboembolism. Methods: Three-dimensional (3D) cardiac reconstructions of the LAA were performed from CT scans of 182 healthy patients and 142 patients with AF. Parameters measured included LAA systolic and diastolic volumes, LAA ejection fraction (LAAEF), body surface area (BSA) indexed LAA volumes for all patients. Systolic and diastolic left atrium (LA) volumes, LA EF, BSA indexed volumes for “AF group”. The CHA2DS2-VASc score (divided in 4 groups) was calculated for “AF group”.

Results: 181 and 142 patients were included, respectively in the “healthy” and “AF” group. We showed that LAAEF was significantly lower in AF group (p=0,0014). A subgroup analysis with the 81 AF patients who had a sLAV < 130 ml showed there was no significant difference for LAAEF with healthy patients despite it was lower (p=0,113).

In “AF group”, the LAA EF significantly decreased when the diastolic and systolic left atrium volumes increased (p<0,001 for both). The LAA EF significantly increased when the left atrium ejection fraction increased (p<0,001). The LAA EF significantly decreased when the BSA iVol max increased (p<0,001). There was no significant difference between the 4 CHA2DS2-VASc groups in LAAEF and iVolmax.

Conclusion : LAAEF was significantly lower in AF group and probably increased their thromboembolic risk. The CHA2DS2-VASc score was not correlated to the LAAEF. A cohort study should be realized to know if LAAEF can be an independent factor for thromboembolism.