Abstract 4125500: Obesity-Related Left Atrial Functional Change Becomes Apparent in Infancy

Background: Impaired left atrial (LA) function is observed in obese patients, however, there is little information on when LA dysfunction begins to appear. To clarify this issue, we assessed LA volume and function in obese infants. Methods: Two-dimensional speckle-tracking echocardiography was performed in 96 infants aged 4 months. Subjects were divided into 3 groups according to body mass index (BMI): normal (n=53), <17 kg/m 2 ; overweight (n=28), 17 to 19.9 kg/m 2 ; obese (n=15), ≧20 kg/m 2 . LA maximal volume, LA minimal volume, and LA pre-atrial contraction volume and LA longitudinal strain (reservoir, conduit, and booster) were measured. LA total emptying fraction, passive emptying fraction, and active emptying fraction were calculated. Results: Systolic blood pressure was significantly higher in the obese group than in the normal group (Table). LA maximal volume, minimal volume, and pre-atrial contraction volume increased significantly with increasing BMI (r = 0.53, 0.54, and 0.63, respectively, p <0.01). Compared with the normal group, reservoir LA strain was significantly lower in the overweight and obese groups. Conduit LA strain and passive emptying fraction were significantly lower in the overweight and obese groups than those in the normal group (Table). Reservoir LA strain, conduit LA strain, and passive emptying fraction decreased significantly with increasing BMI (r = -0.28, -0.27, and -0.33, respectively, p <0.01). There was no significant difference in booster LA strain among the 3 groups. Compared with the normal group, LA active emptying fraction was significantly higher in the obese group (Table). Conclusions: Higher BMI is associated with impaired reservoir and conduit LA function and higher booster LA pump function, which may be compensatory. Thus, obesity-related changes in LA functional begin to appear in infancy. Our data support prevention of obesity in early childhood because higher BMI is responsible for significant changes in LA function in early life.