Decreased left atrial appendage emptying velocity (LAAV) is a known predictor of LAA thrombus in atrial fibrillation (AF). The aim of our study was to identify which of the clinical risk factors for LAA thrombus are associated with decreased LAAV.
The study included 1476 consecutive AF patients who underwent transesophageal echocardiography (TEE) before AF direct current cardioversion or ablation in two high-reference cardiology departments. Patients were divided into two groups: 71 (4.8%) patients with LAAV<20cm/s and 1405 patients (95%) with LAAV≥20cm/s.
Compared to patients with LAAV ≥20cm/s, those with decreased LAAV were older, more often had non-paroxysmal AF, were burdened with more concomitant diseases (including hypertension, diabetes, vascular disease, and heart failure [HF]) with higher median CHA DS -VASc score (3 [2-4] vs 2 [1-3], p<0.0001), and had lower glomerular filtration rate (GFR). Prevalence of LAA thrombus was higher in patients with decreased LAAV compared to those with LAAV≥20cm/s (20% vs 4.6%, p<0.0001). In patients with decreased LAAV, there was no difference in the frequency of LAA thrombus between those treated with VKA and those receiving NOAC, while in patients with LAAV≥20cm/s a trend was observed towards a benefit with NOAC. In multivariate logistic regression, non-paroxysmal AF, HF and age≥65 years predicted both LAAV<20cm/s and LAA thrombus, while GFR<60mL/min/1.73 m predicted only the presence of LAA thrombus.
One in five AF patients with decreased LAAV had LAA thrombus, regardless of the type of OAC. Non-paroxysmal AF, HF and age≥65 years might increase LAA thrombus risk via reduced LAAV.

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