| Objective: This study aimed to analyze normal reference values of left ventricular peak systolic longitudinal strain(SL)and strain rate(Sr L)in healthy children at different ages using two-dimensional speckle tracking imaging(2D-STI).Methods: This study analyzed echocardiogram of 341 healthy children.They were divided into six groups according to age: group 1)0–28 days old,n=22;group 2)28 days to 1 year old,n=54;group 3)1–3 years old,n=60;group 4)3–6 years old,n=81;group 5)6–10 years old,n=62;and group 6)10–18 years old,n=62.2D-STI was performed in the three apical projections of the left ventricle(LV).The regional longitudinal peak systolic strain and strain rate of LV were measured in 18 segments and averaged to provide peak systolic global longitudinal strain(GLS).Results: Statistical significances were found in three segments of the same wall.Furthermore,peak systolic SL and Sr L gradually increased from the basal segment to the apical segment.Regional and global myocardial SL gradually increased with increasing age,except in the basal and middle segments of the posterior wall,for instance,SL(group 1)<SL(group 2)<SL(group 3,4,5)<SL(group 6).We found that regional myocardial SL had a positive correlation with age,among the most remarkable correlation in the apical segment of the lateral wall(r = 0.567,P < 0.01).However,they were found to have a negative correlation with heart rate,in which the middle segment of the lateral wall was the most apparent(r = –0.529,P < 0.01).We found global myocardial SL was positive influenced by age(r = 0.681,P < 0.01)and negative influenced by heart rate(r = –0.658,P < 0.01).Conclusions: This study preliminarily analyzed left ventricular peak systolic SL and Sr L among different age in healthy children.It provided normal reference values for assessing LV regional myocardial systolic dysfunction at different ages and laid the foundation for further exploring myocardial mechanics. |
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