Background:
Obesity (OB) and hypertension (HTN) are risk factors for early cardiovascular disease (CVD). The aim of this study was to determine the effect of OB and HTN on myocardial mechanics in children using speckle-tracking echocardiography (STE).
Methods:
Echocardiograms (echo) and ambulatory blood pressure monitors were performed in children referred for HTN from 2009 to 2014. Traditional echo Doppler indices, mass and volume parameters, 24-hr systolic blood pressures (24SBP) and 24-hr diastolic BP indices were obtained. Post-processing was performed on the 2D gray scale images of LV in apical 4-chamber and parasternal short axis mid-papillary views to obtain strain indices (Image Arena, Tomtec). Associations of obesity and BP to the myocardial indices were explored independently using Spearman correlation coefficient.
Results:
Among 107 patients, 6 - 21 yrs age, 79.4% were males; 42% OB and 53% were hypertensive. Mean Z scores for BMI were 1.5 ± 1.1 and SBP were 1.5 ± 1.2. Mean LV mass (LVM, 2D area-length) was 131
+
42.8 gms, LVMI
2.7
was 40.7
+
9.6 gms, LVM/volume ratio was 0.94
+
0.17. Mean mitral septal E/e’ was 8.3
+
2.1, lateral E/e’ was 5.9
+
1.5 and mitral E/A ratio was 1.8
+
0.4. The mean global longitudinal strain (GLS) was – 17.7
+
3.6, global circumferential strain (GCS) was -20.4
+
3.8, average radial strain (ARS) was 22
+
11.9, average longitudinal strain rate (ALSR) was -1.0
+
0.35 and average circumferential strain rate (ACSR) was -1.5
+
0.5 for all patients. BMI Z scores positively correlated with LVM (r=0.38, p<0.01), LVM/vol (r=0.32, p<0.01), mitral E/e’ (r=0.28, p<0.01), LVMI
2.7
(r=0.5, <0.01). Increased BMI negatively correlated to GLS, GCS and ACSR (r=0.3, p<0.01). Higher SBP, diastolic and mean BP were associated with higher mitral medial E/e’ (r=0.3, p<0.01), however did not have statistically significant correlations to strain indices.
Conclusions:
Obesity causes adverse cardiac remodeling in obese children. This may provide insights into mechanisms of long-term CV effects of obesity. Myocardial effects of HTN were not apparent, possibly due to heterogeneity of the study group and low power.
