Characterisation of atrial and ventricular myocardial deformation indices with increasing body mass index

Abstract

Background: Little is known about changes in cardiac structure and function in the obese due to challenges in adjustment of echocardiographic parameters to body size. Our study sought to assess the changes in myocardial deformation indices in patients with different classes of obesity. Method(s): Patients without cardiac history or metabolic risk factors (hypertension and/or diabetes mellitus) and who had normal cardiac function were recruited from our outpatient echocardiography service. We divided the cohort into five groups based on BMI ranges (Group 1: normal BMI [n=20], Group 2: Overweight [n=20], Group 3: Obese I [n=20], Group 4: Obese II [n=20], Group 5: Obese III [n=20]) and evaluated the changes in myocardial strain with increasing BMI. We excluded patients with significant valvular abnormalities, congenital heart disease and those with poor-quality images. Two-dimensional speckle tracking strain was performed using vendor independent software (TomTec imaging systems). Result(s): A total of 100 patients (mean age 39.35+/-11.15, 34% male) were included. With increasing BMI, a significant downward trend in right ventricular (RV) free wall strain (p<0.01) and left atrial (LA) strain (p<0.01) was noted. Of interest, a similar trend was not observed with left ventricular (LV) strain. A significant upward trend in RV systolic pressure (p<0.01) and tricuspid Vmax (p=0.04) was also noted with increasing BMI. Conclusion(s): In obese patients without cardiac disease or metabolic risk factors, increasing BMI was associated with a significant reduction in LA strain and RV free wall strain.