RESUMEN
BACKGROUND: Echocardiographic myocardial work is a new load-independent echocardiographic technique to quantify left ventricle (LV) systolic performance. Our aim was to establish normal values for echocardiographic myocardial work in a large population of healthy children. METHODS: For all the subjects 4-, 2-, and 3-chamber-view videos were stored. The following parameters were obtained by offline analysis: the global myocardial work (GMW), the global myocardial constructive work (GCW), the global myocardial wasted work (GWW), and the global myocardial work efficiency (GWE). Age, weight, height, heart rate, and body surface area (BSA) were used as independent variables in the statistical analysis. RESULTS: In all, 516 healthy subjects (age range, 1 day-18 years; median age, 8.2 ± 5.3 years; 55.8% male; body surface area (BSA) range, 0.16 to 2.12 m2) were included. GWI, GCW, and GWW increased with weight, height, and BSA (ρ ranging from 0.635 to 0.226, p all < 0.01); GWI and GCW positively correlated with age (ρ 0.653 and 0.507). After adjusting for BSA differences, females showed higher mean GWI (p = 0.002) and GCW values (p < 0.001), thus Z-score equations for gender have been presented. CONCLUSIONS: We provided MW values in a large population of healthy pediatric subjects including lower ages. MW values increased with age and body size and, interestingly, were higher in females than in men. These data cover a gap in current nomograms and may serve as a baseline for the evaluation of MW analysis in children with congenital and acquired heart diseases.
RESUMEN
BACKGROUND: Although coronary artery nomograms in children have been published, data on Caucasian children are lacking. The aim of this study is to provide: (i) a full dataset of coronary artery diameters in healthy children and (ii) a comparison among major previous nomograms. MATERIALS AND METHODS: We prospectively evaluated 606 healthy subjects (age range, 1 days-<18 years; median age 8.7 years; 62.5% male). Coronary artery measurements in a short-axis view were performed. Age, heart rate, and body surface area (BSA) were used as independent variables in different analyses to predict the mean values of each measurement. To assess the accuracy of the predictive models of different studies, a Z-score calculator was created using Lopez's nomograms for comparison. RESULTS: The association with BSA was found to be stronger, and was used for normalization of our data. The best-fit models, satisfying the assumption of homoscedasticity and normality of residuals and showing the highest R2 scores, were logarithmic (ln[y] = a + b*ln[x]). Predicted values and Z-score boundaries by BSA are provided. Our ranges of normality are slightly lower than those, diverging from -0.22 to -0.59 Z-scores for the left main coronary artery and from -0.23 to -0.3 Z-scores for the right coronary artery. CONCLUSIONS: We report a complete dataset of normal echocardiography coronary artery diameter (including new measures of the proximal origin) values in a large population of healthy children. Our data were statistically like those of north American nomograms.
