Abstract 10335: Increased Left Atrial Minimum Volume Index is Associated with Low Left Atrial Appendage Emptying Velocity

Abstract

Background: Increased left atrial minimum volume indexed by body surface area (LAVImin) is a risk factor for ischemic stroke. The mechanism underlying this association is not well defined. Hypothesis: We hypothesized that increased LAVImin is associated with low left atrial appendage emptying velocity (LAAV). Methods: We reviewed medical records of 167 patients who underwent transesophageal echocardiography (TEE) within twelve months of transthoracic echocardiography (TTE), which was obtained during sinus rhythm, in a tertiary care medical center from 2017 to 2020. We used the student’s T-test to compare the means of continuous variables. We used logistic regression analysis to estimate the odds ratio of LAVImin (per unit increase) for low LAAV (≤40 cm/s) adjusting for CHA 2 DS 2 VASc variables and heart rate during TEE. We also stratified our analysis by rhythm during TEE. Results: In our final cohort, patients with LAAV≤40 cm/s and LAAV>40 cm/s had a mean (SD) LAVImin of 27.6 (16.6) ml/m 2 and 20.3 (12.0) ml/m 2 , respectively (P=0.003). In our subgroup of sinus rhythm TEEs, patients with LAAV≤40 cm/s and LAAV>40 cm/s had a mean (SD) LAVImin of 22.5 (12.8) ml/m 2 and 20.0 (12.4) ml/m 2 , respectively (P=0.30). In our subgroup of atrial fibrillation TEEs, patients with LAAV≤40 cm/s and LAAV>40 cm/s had a mean (SD) LAVImin of 39.0 (19.7) ml/m 2 and 23.7 (10.6) ml/m 2 , respectively (P=0.01). LAVImin was independently associated with low LAA emptying velocity. When stratified by rhythm during TEE, this association was only significant for patients in atrial fibrillation (OR 1.17 [1.06-1.39], p<0.01), and not in sinus rhythm (OR 0.99 [0.96-1.03], p= 0.75). Conclusion: The association between increased LAVImin and low LAAV is dependent on heart rhythm.