Morphological and Functional Changes of the Left Atrium in Obesity

Abstract

Obesity-related atrial cardiomyopathy is a clinical entity characterized by a variety of functional and structural abnormalities in the atria's myocardium. This study aimed to investigate the morphological and functional alterations of the left atrium (LA) in overweight and obese subjects.The study included 56 subjects aged 47+9.6 years, categorized into 4 groups according to their body mass index (BMI): group 1 -overweight (BMI 25-29.9 kg/m 2 ); group 2 -class I obesity (BMI 30-34.9 kg/m2); group 3 -class II obesity (BMI 35-39.9 kg/m 2 ) and group 4 -class III obesity (BMI >40 kg/m 2 ). All subjects underwent two-dimensional (2D) conventional echocardiography and speckle tracking myocardial deformation assessment. Left atrial enlargement (LAE) was registered in all four groups, with an average value of LA diameter 40.0±4.9 mm and LA volume (LAV) indexed to height (LAVh) 35.0 +7.8 ml. Global longitudinal strain (GLS%) and circumferential strain (GCS%) of LA were lower than reference normal values in all groups. LAV indexed to body surface area (LAVI) correlated with hip circumference (r=0.264; p=0.049), whereas LAVh correlated with waist and hip circumference (r=0.378; p=0.004). Linear regression analysis showed that hip circumference was a predictive factor for increasing LAVI (B=0.114; p=0.049; 95%CI 0.000-0.227) and LAVh (B=0.266; p =0.0001; 95%CI 0.129-0.403).LAVh is a clinically useful echocardiographic parameter to assess LA size in obese population. A sensitive method for detecting subclinical functional alterations of LA is assessment of its speckle tracking longitudinal strain.