Abstract 5714: Influence of Body Mass Index on Early Diastolic Untwisting Velocity in Healthy Children
Background: Childhood obesity is increasingly prevalent in the community and is predictive of adverse cardiovascular outcomes in adulthood. We hypothesised that increased body mass index (BMI) in children has an adverse influence on left ventricular (LV) untwisting, a sensitive marker of LV function that reflects a key process in the transition between LV relaxation and suction.
Methods: Cardiac structure and function were assessed by transthoracic echocardiography. LV twist mechanics were quantitated using 2-dimensional speckle tracking imaging of the LV base and apex in short axis. Univariate associations of LV untwisting velocity (Er) were evaluated using Spearman’s correlation analysis. Significant univariate predictors (p≤0.10) were included into multivariable regression analysis to determine the independent relationship between body mass and Er (rad/s).
Results: Of the first 150 children assessed (age 10.2 ± 0.3 years; 83 boys), the mean BMI was 18.2 ± 2.8 kg/m2. In univariate analysis, Er was inversely related to BMI (ρ= −0.13, p=0.10), LV end-diastolic diameter (ρ= −0.13, p=0.10) and LV end-systolic diameter (ρ= −0.28, p<0.001); and positively correlated with LV torsion (ρ=0.55, p<0.001), LV twisting velocity (ρ=0.29, p<0.001), early diastolic annular velocity (e′) (ρ=0.13, p=0.10), LV ejection fraction (EF) (ρ=0.14, p=0.09) and heart rate (ρ=0.18, p=0.03). There was no correlation between Er and LV relative wall thickness or mass index (p>0.25). In multivariable analysis, body mass index was independently associated with Er, independent of LV torsion, heart rate, EF, LV chamber size and e′ (Table⇓).
Conclusion: Increased body mass is independently related to lower LV untwisting velocity during early diastole in healthy children. Additional studies are required to evaluate whether lifestyle measures to reduce body mass will attenuate further deterioration in LV diastolic relaxation and suction.