Abstract 8545: Left Atrial Function Assessed by Speckle Tracking Echocardiography as a Predictor of New-Onset Atrial Fibrillation: Results from a Prospective Study in 580 Adults

Abstract

Background: Risk stratification for atrial fibrillation (AF) based on left atrial (LA) remodeling may have a major public health impact. Although LA volume (LAV) or LA dimension have been proposed as predictors of AF, LA function have not yet been fully examined. Using speckle tracking echocardiography (STE), assessment of LA structure and function is feasible. The aim of this prospective study was to evaluate LA function for the prediction of increased risk of new-onset nonvalvular AF. Methods: We examined LA phasic emptying function (EF), strain rate (SR) and volume in apical 4-chamber view using STE in 580 consecutive adults (age 64±17) without a history of atrial arrhythmia and mitral valve disease. Left ventricular mass, ejection fraction and E/e’ and coronary risk factors were also evaluated. Then, we followed occurrence of AF prospectively. Results: During a mean follow-up period of 2.4±0.3 years, 32 subjects (age 73±9, 18 men) developed electrocardiographically-confirmed AF. Subjects with new-onset AF had lower LA active EF (16±5% vs. 28±8%, p<0.001) and lower LA SR at atrial contraction (-0.9±0.2 S -1 vs. -1.4±0.5 S -1 , p<0.001), but larger maximum LAV index (59±12 ml/m 2 vs. 46±16 ml/m 2 , p<0.001) compared with non-AF subjects at baseline. In multivariate logistic regression analysis, LA active EF was the only independent predictor of new-onset AF. Using an LA active EF cutoff of 20%, the sensitivity and specificity for new-onset AF based on receiver operator characteristic curve analysis were 88% and 81%, respectively (area under the curve (AUC): 0.92), whereas those of maximum LAV were 94% and 53% (AUC: 0.77). Conclusion: Reduced LA active EF (booster pump function) assessed by STE independently predicts the risk of new-onset AF, suggesting a stronger association between LA functional remodeling and AF than between LA size and AF.Noninvasive echocardiographic assessment of LA phasic function, especially LA ative contraction (booster pump function), in sinus rhythm would provide incremental value for the risk stratification and be a more useful predictor for new-onset AF than LA size.