Abstract 8697: Left Atrial Appendage Function Assessed by Speckle Tracking Echocardiography as a Predictor of Thrombus in Patients with Permanent Atrial Fibrillation
Background: Left atrial appendage (LAA) thrombus is a high risk factor of thromboembolism in patients with atrial fibrillation (AF). Spontaneous echo contrast (SEC) and LAA emptying velocity are echocardiographic predictors of LAA thrombus and CHADS2 score is used as a risk stratification of thrombus. However, LAA contractile function may be an important determinant of thrombus. Thus, we assessed the hypothesis that LAA emptying function (EF) would be more useful to predict LAA thrombus in AF.
Methods: Using speckle tracking echocardiography (STE) (ACUSON sequoia 512, Siemens), time-LAA or LA volume curve can be automatically provided. LAAEF and LAEF were measured by STE and compared with manual tracing method using transesophageal (TEE) and transthoracic echocardiography in consecutive 142 patients with AF and treated with warfarin. They were grouped according to the presence of thrombus; AF with thrombus (n=38, age 69±10, 30 men) and AF without thrombus (n=104, age 65±12, 80 men). LAAEF and LAEF were defined as (maximum - minimum volume) / maximum volume x 100% during a cardiac cycle. SEC score, LAA peak and mean velocity, left ventricular ejection fraction and LA dimension were also measured. Average values of 3 cardiac cycles were analyzed.
Results: LAAEF and LAEF by STE correlated with manual tracing method (r=0.98, r=0.95, respectively, p<0.001). Patients with AF and thrombus were older and had more prior strokes, longer AF duration and reduced LAAEF (Table). Using 20% of LAAEF as a cutoff value, sensitivity was 92% and specificity was 88% for thrombus. In multivariate analysis, LAAEF and age were independent predictors of LAA thrombus.
Conclusion: LAA thrombi appeared to exist in elderly patients with AF and more reduced LAAEF compared to AF with preserved LAAEF despite no difference in PT-INR, suggesting that LAA thrombus formation depends on LAA contractility. LAAEF by STE using TEE may be a useful predictor of LAA thrombus in patients with AF and warfarin therapy.
- © 2011 by American Heart Association, Inc.