Left atrial (LA) appendage flow velocity (LAAFV) is a classic but invasive predictor of thromboembolic events in patients with atrial fibrillation (AF). We aimed to explore the usefulness of LA diameter (LAD) combined with CHA₂DS₂-VASc score, which is easily available and non-invasive, as a novel score for predicting a decrease in LAAFV in non-valvular AF (NVAF).

In total, 716 consecutive NVAF patients who underwent transesophageal echocardiography were divided into the decreased LAAFV (< 0.4 m/s) and preserved LAAFV (≥ 0.4 m/s) groups.

The decreased LAAFV group had a larger LAD and a higher CHA₂DS₂-VASc score than the preserved LAAFV group (P < 0.001). Multivariate linear regression indicated that brain natriuretic peptide (BNP) concentration, persistent AF, LAD, and CHA₂DS₂-VASc score were remained inversely associated with LAAFV. Moreover, multivariate logistic regression revealed that BNP concentration (odds ratio [OR] 1.003, 95% confidence interval [CI] 1.001–1.005, P = 0.003), persistent AF (OR 0.159, 95% CI 0.102–0.247, P < 0.001), and LAD (OR 1.098, 95% CI 1.049–1.149, P < 0.001) were independent factors for a decrease in LAAFV. A novel score, LAD combined with CHA₂DS₂-VASc score, was more accurate for predicting a decrease in LAAFV among NVAF patients (area under the curve was 0.733).

Enlarged LAD was independent risk factor for a decrease in LAAFV among NVAF patients. LAD combined with CHA₂DS₂-VASc score enhanced the predictive ability for a decrease in LAAFV among NVAF patients.