Echocardiographic reference z scores of right ventricular dimension and systolic function of children aged 5–12 years

BACKGROUND: Reference values for right ventricular dimension and systolic function in Nigerian children are scarce despite their high burden of right ventricular abnormalities. Reference values from other countries may not be suitable for use in Nigerian children because of possible racial variations in cardiac size. PURPOSE: To develop reference values for right ventricular dimension and systolic function in healthy Nigerian children aged 5-12 years. METHODS: This descriptive cross-sectional study conducted between July and November 2019 included 480 healthy boys and girls aged 5-12 years. The participants were randomly selected from 6 primary schools in the Ikeja Local Government area of Lagos State and their weights and heights measured. Body mass index and body surface area were calculated. Echocardiography was performed at rest in the left lateral position. RESULTS: The right ventricular end-diastolic basal diameter (RVD1), right ventricular end-diastolic mid-cavity diameter (RVD2), and right ventricular end-diastolic length (RVD3) were obtained. The right ventricular end-diastolic basal diameter (RVD1), right ventricular end-diastolic mid-cavity diameter (RVD2), and right ventricular end-diastolic length (RVD3) were obtained, as well as tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler-derived right ventricular systolic excursion velocity (S'). The overall mean±standard deviation (SD) values for RVD1, RVD2, RVD3, TAPSE, and S' were 32.95±4.2, 25.86±3.5, 54.57±7.5, 20.11±2.3, and 18.24±2.2, respectively. Age- and sex-specific mean and SD values of the same cardiac indices were determined. Z score charts and the mean± 2SD right ventricular dimensions and systolic function were generated. All right ventricular dimensions were positively correlated with weight, height, body surface area, and body mass index. Only height correlated consistently with TAPSE and S'. CONCLUSION: The observed mean right ventricular dimension indices differed from those derived elsewhere, suggesting that values from other countries may be inappropriate for Nigerian children. These reference values are applicable in daily clinical practice.