Body mass index and risk of left atrial thrombus in patients with atrial fibrillation.

This study sought to assess the impact of body mass index (BMI) on the risk of left atrial (LA)/left atrial appendage (LAA) thrombus in patients with atrial fibrillation (AF) before catheter ablation. From January 2007 to March 2008, 433 consecutive patients with nonvalvular AF were enrolled. Patients with valvular heart disease, deep vein thrombosis, or pulmonary embolism were excluded. All patients underwent transesophageal echocardiography. Twenty-six of 433 patients (6.0%) had LA/LAA thrombus and the patients with thrombus had a significantly higher BMI (27.9 +/- 3.1 vs 26.0 +/- 3.3 kg/m(2), p = 0.005). The area under the receiver operating characteristic curve of BMI predicting thrombus was 0.662. With a cut-off point of 27.0 kg/m(2), the sensitivity and specificity of BMI for the diagnosis of thrombus were 69.2% and 83.1%, respectively. The incidence of LA/LAA thrombus was 10.6% in patients with BMI > or =27.0 kg/m(2) versus only 3.0% for patients with BMI <27.0 kg/m(2) (p = 0.001). In multivariable analysis, BMI > or =27.0 kg/m(2) (odds ratio 4.02, 95% confidence interval 1.19 to 13.55, p = 0.025), Cardiac Failure, Hypertension, Age, Diabetes, Stroke Doubled score > or =2, and nonparoxysmal AF were independent risk factors of LA/LAA thrombus. In conclusion, BMI > or =27.0 kg/m(2) is an independent risk factor of LA/LAA thrombus in patients with AF.