Body mass index can predict left ventricular diastolic filling in asymptomatic obese children

To examine the effects of body mass index on left ventricular diastolic function, flow velocity patterns of the pulmonary vein and mitral valve were measured by pulse Doppler echocardiography in 21 asymptomatic obese children and were compared with those of an age-matched control population. The degree of obesity was calculated as (actual body mass index/ideal body mass index -1) x 100. The pulmonary venous flow indexes were peak systolic (S) and diastolic (D) velocities and peak D/S. The mitral inflow indexes were peak velocities of early diastole (E) and atrial contraction (A) and peak E/A. The pulmonary venous flow velocity pattern in obese patients was characterized by unchanged peak S, decreases in peak D (43 +/- 7 vs 51 +/- 8, p < 0.01) and peak D/S (0.98 <plus/minus> 0.19 vs 1.29 +/- 0.20, p < 0.01), suggesting the reduction in the early diastolic filling. The peak D/S decreased significantly with an increase in the percentage body mass index (r = -0.84, p < 0.01). In contrast to the pulmonary venous flow pattern (peak D > peak S) as seen in normal controls, all of the obese patients with >70% over body mass index had abnormal pulmonary venous flow velocity patterns (peak D < peak S). The mitral flow velocity pattern in obese patients was also characterized by a decrease in early diastolic filling. However, these indices did not correlate with an increase in the percentage over body mass index. This study suggests that body mass index predicts the abnormality of left ventricular diastolic filling assessed by pulmonary venous flow patterns.