Background: Obesity in adulthood is associated with a higher occurrence of atrial arrhythmias. Obese children, without arterial hypertension, may be a unique clinical opportunity to evaluate the effect of obesity, per se, on atrial myocardial function, excluding the influence of possible comorbidities. We sought to define the preclinical effects of obesity on the atrial function of healthy children with excess weight who have no other clinically appreciable cause of heart disease, by using the more sensitive ultrasonic-derived strain (S) and S rate imaging.
Methods: We studied 320 children divided into two groups: obese children (group O; n = 160; age 12 +/- 3 years); and healthy lean children, comparable for age, sex, and pubertal stage (referents; n = 160; mean age 12 +/- 3 years).
Results: Systolic blood pressure (BP) and diastolic BP, as well as 24-hour systolic BP and 24-hour diastolic BP were comparable between groups. Left ventricular mass/height(2.7) and left atrial dimensions were increased (P < .0001) in group O (46 +/- 12 g/m(2.7)) compared with referents (31 +/- 14 g/m(2.7)). Standard echocardiographic indices of global left ventricular systolic function were similar in the two groups. Obese children showed atrial peak systolic S rate (2.5 +/- 1.2 (s-1)) values lower (P < .0001) than that of referents (4.9 +/- 1.6(s-1)) in both left and right atria. In multivariable analysis, average peak systolic atrial S was significantly correlated with glycemia (P < .05, coefficient -0.23), body mass index (P < .01, coefficient -0.19), and left ventricular mass (P < .05, coefficient -0.17).
Conclusions: Our study demonstrated that obesity, in absence of hypertension, is associated with reduced atrial myocardial deformation properties already in childhood involving both right and left atria.