Average e' velocity on transthoracic echocardiogram is a novel predictor of left atrial appendage sludge or thrombus in patients with atrial fibrillation

Background: Studies have demonstrated the value of transthoracic echocardiogram (TTE) diastolic parameters in predicting left atrial appendage (LAA) thrombus; however, these studies have been small. We aim to clarify the relationship between TTE diastolic parameters, in particular average e', and LAA thrombus or sludge. Methods: A case-control review was conducted of subjects with non-valvular atrial fibrillation (n = 2263) who had undergone TEE (transesophageal echocardiogram) and had a TTE within 1 year of TEE. Cases of LAA sludge or thrombus were matched to controls by age, sex, left ventricular ejection fraction (LVEF), and anticoagulation status. Results: Forty-three subjects (mean age 73 +/- 12, 65% male, LVEF 47%, 44% on anti-coagulation) with LAA sludge or thrombus were identified. Compared to matched controls, average TTE e' (7.3 +/- 2.1 cm/s vs 8.7 +/- 2.1 cm/s, P < 0.001) and the E:e' ratio (15 +/- 7 cm/s vs 12 +/- 5 cm/s; P = 0.005) were significant predictors of LAA sludge or thrombus. Average TTE e' value of > 11 cm/s had 100% sensitivity for ruling out LAA sludge or thrombus. Conclusion: In individuals with atrial fibrillation, average e' > 11 cm/s on TTE is a promising independent predictor of the absence of LAA sludge or thrombus on TEE.