Background The establishment of the range of reference values and associated variations of two-dimensional speckle-tracking echocardiography (2DSTE) derived left ventricular (LV) strain is a prerequisite for its routine clinical adoption in pediatrics. The aims were to perform a meta-analysis of normal ranges of LV global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS) measurements derived by 2DSTE in children and identify confounding factors that may contribute to variances in reported measures. Methods A systematic review was launched in Medline, Embase, Scopus, CINAHL, and Cochrane. Search hedges were created to cover the concepts of pediatrics, speckle-tracking echocardiography, and left heart ventricle. Two investigators independently identified and included studies if they reported the 2DSTE derived LV GLS, GCS or GRS. The weighted mean was estimated by using random-effects with 95% confidence interval (CI), heterogeneity was assessed by the Cochran's Q statistic and the inconsistency index (I2) and publication was evaluated using the Egger test. Effects of demographic (age), clinical, and vendor variables were assessed in a meta-regression. Results The search identified 2325 children from 43 data sets. The reported normal mean values of GLS among the studies varied from -16.7% to -23.6% (mean -20.2%, 95% CI -19.5% to -20.8%), GCS varied from -12.9% to -31.4% (mean -22.3%, 95% CI -19.9% to -24.6%) and GRS, varied from 33.9% to 54.5 % (mean 45.2 95% CI 38.3 to 51.7). 26 studies reported LS only from the apical 4-chamber view with a mean of -20.4%, (95% CI -19.8% to -21.7%). 23 studies reported CS (mean, -20.3%, 95% CI -19.4% to -21.2%) and RS (mean, 46.7%, 95% CI 42.3% to 51.1%) from the short axis view at the mid-ventricular level. A significant apex-to-base segmental longitudinal strain (SLS) gradient (P < .01) was observed in the LV free wall. There was significant between- study heterogeneity and inconsistency (I2 > 94% and P < .001 for each strain measure), which was not explained by age, gender, body surface area, blood pressure, heart rate, frame rate, FR/HR ratio tissue-tracking methodology, location of reported strain value along the strain curve, ultrasound equipment, or software. These metaregression showed that these effects were not significant determinants of variations among normal ranges of strain values. There was no evidence of publication bias (P = .40). Conclusions This study defined reference values of 2DSTE derived LV strain in children on the basis of a meta-analysis. In healthy children, the mean LV global longitudinal strain value is -20.2%, (95% CI -19.5% to -20.8%), mean global circumferential strain -22.3%, (95% CI -19.9% to -24.6%), and mean global radial strain is 45.2%, (95% CI 38.3% to 51.7%). LV segmental longitudinal strain has a stable apex-to-base gradient that is preserved throughout maturations. Although variations among different reference ranges in this meta-analysis were not dependent on differences in demographic, clinical, or vendor para...

Background Pulmonary artery acceleration time (PAAT) is a non-invasive method to assess pulmonary hemodynamics, but lacks validity in children. This study sought to evaluate the accuracy of Doppler echocardiography (DE) derived PAAT in predicting right heart catheterization (RHC) derived pulmonary arterial pressure (PAP), pulmonary vascular resistance (PVR) and compliance in children. Methods Prospectively acquired and retrospectively measured DE derived PAAT and RHC derived systolic PAP (sPAP), mean PAP (mPAP), index PVR (PVRi) and compliance were compared by regression analysis in a derivation cohort of 75 children (median age, 5.3 years; 1.3–12.6) with wide ranges of pulmonary hemodynamics. To account for heart rate variability, PAAT was adjusted for right ventricle ejection time (RVET) and corrected by the RR interval. Regression equations incorporating PAAT and PAAT:RVET from the derivation cohort were then evaluated for the accuracy of its predictive values for invasive pulmonary hemodynamics in a validation cohort of 50 age- and weight- matched children with elevated PAP and PVR. Results There were significant inverse correlations between PAAT and RHC derived mPAP (r = −0.82) and PVRi (r= −0.78) and direct correlation (r= 0.78) between PAAT and pulmonary compliance in the derivation cohort. For detection of pulmonary hypertension (PRVi > 3 WU x m2 and mPAP > 25 mmHg), PAAT < 90 msec and PAAT:RVET < 0.31 resulted in a sensitivity of 97% and a specificity of 95%. In the derivation cohort, the regression equations relating PAAT with mPAP and PVRi were: mPAP = 48 – 0.28 x PAAT and PVRi = 9 –0.07 x PAAT. These PAAT integrated equations predicted RHC measured pulmonary hemodynamics in the validation cohort with good correlations (r = 0.88, 0.83 respectively), small biases (<10%), and minimal coefficient of variation (<8%). Conclusions PAAT inversely correlates with RHC measured pulmonary hemodynamics and directly correlates with pulmonary arterial compliance in children. The study established PAAT based regression equations in children to accurately predict RHC derived PAP and PVR.

Background We aimed to determine the maturational changes in systolic ventricular strain mechanics by two-dimensional speckle tracking echocardiography in extreme preterm neonates from birth to one year of age, and discern the impact of common cardiopulmonary abnormalities on the deformation measures. Methods In a prospective multi-center study of 239 extreme preterm infants (< 29 weeks gestation at birth), left ventricle (LV) global longitudinal strain and systolic strain rate (GLS, GLSRs), interventricular septal wall (IVS) GLS and GLSRs, right ventricle free wall longitudinal S and SR (RV FWLS, FWLSRs), and segmental LS (SLS) in the RVFW, LVFW and IVS were serially measured at Days 1, 2, 5–7, 32 weeks and 36 weeks post-menstrual age (PMA), and one year corrected age (CA). Premature infants who developed bronchopulmonary dysplasia (BPD) or had echocardiographic findings of pulmonary hypertension (PH) were analyzed separately. Results In uncomplicated preterm infants (n=103, 48%), LV GLS and GLSRs remained unchanged from Day 5–7 to one year CA (p=0.60 and 0.59). RV FWLS, FWLSRs and IVS GLS and GLSR significantly increased over the same time period (p < 0.01 for all measures). A significant base-to-apex (highest to lowest) SLS gradient (p < 0.01) in the RVFW and a reverse apex-to-base gradient (p < 0.01) existed in the LVFW. In infants with BPD and/or PH (n=119, 51%), RV FWLS and IVS GLS were significantly lower (p < 0.01), LV GLS and GLSRs were similar (p=0.56), and IVS SLS persisted as an RV dominant base-to-apex gradient from 32 weeks PMA to one year CA. Conclusions This study tracks the maturational patterns of global and regional deformation by 2DSTE in extreme preterm infants from birth to one year CA. The maturational patterns are ventricular specific. BPD and PH leave a negative impact on RV and IVS strain, while LV strain remains stable.

In comparison with infants born at term, infants born preterm exhibit abnormal PAAT at 1-year corrected age irrespective of neonatal lung disease status, suggesting the existence of PVD beyond infancy. PAAT measurements offer a reliable, noninvasive tool for screening and longitudinal monitoring of pulmonary hemodynamics in infants.

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