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 (LAEbsa) or height2 (LAEh2). 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 LAEh2 and 18.3% LAEBSA. The LAEh2 group had significantly lower LASct (12.2% ± 3.2% vs. 13.6% ± 4.5%, p = 0.019) as compared to the patients without LAEh2. Significantly more patients with LA dysfunction would be correctly identified by LAEh2 than by LAEBSA (41.5% vs. 15.0%, p < 0.001). In patients with moderate to severe obesity, the use of LAEh2 identified significantly more patients with decreased LA function. LAVh2 should be preferred over LAVBSA in patients with moderate to severe obesity.

The impact of obesity on early postoperative atrial fibrillation burden.

BACKGROUND: Obesity has been linked to the development of postoperative atrial fibrillation. This study is aimed at investigating the role of body mass index in the evolution of de novo, early postoperative atrial fibrillation by assessing differences between obese and nonobese patients undergoing cardiac surgery. METHODS: Patients with early de novo postoperative atrial fibrillation were included. Continuous cardiac rhythms were recorded during the first 5 postoperative days in obese (N = 67, 66 ± 9 years; 51 [76%] male) and nonobese (N = 89, 69 ± 9; 75 [84%] male) patients without a history of atrial fibrillation undergoing cardiac surgery. Postoperative atrial fibrillation burden was defined as the ratio between total duration of all atrial fibrillation episodes and total recording time (atrial fibrillation burden, %). RESULTS: A total of 1191 (median: 5/patient) postoperative atrial fibrillation episodes were identified in the obese group compared with 1218 (median: 4/patient) in the nonobese group. The median duration and number of prolonged (>60 minutes) postoperative atrial fibrillation episodes were higher in obese patients (250 vs 145 minutes, P = .003, and median of 2 vs 1 episode, P = .031). Obesity was associated with a larger early postoperative atrial fibrillation burden (obese patients: median, 7%; interquartile range, 2.5-19.7 vs nonobese patients: median, 3.2%; interquartile range, 0.5-8.8, P = .001) mainly on the third postoperative day (P = .021). CONCLUSIONS: Obesity predisposes to a larger number of prolonged atrial fibrillation episodes in the early postoperative period after cardiac surgery for coronary artery disease or valvular heart disease. The higher atrial fibrillation burden in the early postoperative period occurred particularly on the third day. Future studies will determine whether obesity prevention may play a key role in reducing the incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery.