Left atrial spontaneous echo contrast occurring in patients with low CHADS₂ or CHA₂DS₂-VASc scores

Left atrial spontaneous echo contrast (LASEC) is common in patients with atrial fibrillation (AF), although scarce information exists on LASEC occurring in nonvalvular AF patients who have low thromboembolic risk scores. We therefore examined prevalence and determinants of LASEC under low CHADS₂ or CHA₂DS₂-VASc scores in these patients.

Among 713 patients who underwent transesophageal echocardiography, 349 with a CHADS₂ score < 2 (CHADS₂ group) (93 women, mean age 65 years) and 221 with a CHA₂DS₂-VASc score < 2 (CHA₂DS₂-VASc group) (39 women, mean age 62 years) were separately examined for clinical and echocardiographic findings.

LASEC was found in 77 patients of CHADS₂ group (22%) and in 41 of CHA₂DS₂-VASc group (19%). Multivariate logistic regression analysis, adjusted for several parameters including non-paroxysmal AF, LA enlargement (LA diameter ≥ 50 mm), left ventricular (LV) hypertrophy, and an elevated B-type natriuretic peptide (BNP) (BNP ≥200 pg/mL) revealed that for CHADS₂ group, non-paroxysmal AF (Odds ratio 5.65, 95%CI 3.08-10.5, P < 0.001), BNP elevation (Odds ratio 3.42, 95%CI 1.29-9.06, P = 0.013), and LV hypertrophy (Odds ratio 2.26, 95%CI 1.19-4.28, P = 0.013) were significant independent determinants of LASEC, and that for CHA₂DS₂-VASc group, non-paroxysmal AF (Odds ratio 3.38, 95%CI 1.51-7.54, P = 0.003) and LV hypertrophy (Odds ratio 2.53, 95%CI 1.13-5.70, P = 0.025) were significant independent determinants of LASEC.

LASEC was present in a considerable proportion of patients with nonvalvular AF under low thromboembolic risk scores. Information on AF chronicity, BNP, and LV hypertrophy might help identify patients at risk for thromboembolism, although large-scale studies are necessary to confirm our observations.