Improved identification of left atrial enlargement in patients with obesity

Accurate standardization of left atrium volume (LAV) in patients with obesity is challenging. The aim of this study was to investigate and to examine the relation between LAV indexed to height² and left atrial function in patients with moderate to severe obesity. Echocardiograms of patients with moderate to severe obesity (body mass index (BMI) ≥ 35 kg/m²) without known cardiac disease were analyzed. LAV was indexed to body surface area (BSA) and height², and patients were divided into those with or without left atrial enlargement (LAE) based on normalization using either BSA (LAE_bsa) or height² (LAE_h2). Using speckle tracking echocardiography, LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct) were assessed as a measure of LA function. LA dysfunction was defined as LASct < 14%. A total of 142 patients were included in the analysis of whom 54.2% had LAE_h2 and 18.3% LAE_BSA. The LAE_h2 group had significantly lower LASct (12.2% ± 3.2% vs. 13.6% ± 4.5%, p = 0.019) as compared to the patients without LAE_h2. Significantly more patients with LA dysfunction would be correctly identified by LAE_h2 than by LAE_BSA (41.5% vs. 15.0%, p < 0.001). In patients with moderate to severe obesity, the use of LAE_h2 identified significantly more patients with decreased LA function. LAV_h2 should be preferred over LAV_BSA in patients with moderate to severe obesity.