Echocardiographic reference ranges in older children and adolescents in sub-Saharan Africa

Echocardiographic nomograms and Z-scores for term Indian neonates

Background

The availability of nomograms is crucial for the correct interpretation of pediatric and neonatal echocardiograms. Echocardiographic Z-score applications/websites use Western nomograms as reference, which may not be an appropriate standard for gauging Indian neonates. Currently available Indian pediatric nomograms either have not included neonates or have not been specifically designed for neonates. This gross underrepresentation of neonates renders available nomograms unreliable for use as standards for comparison.

Objectives

The objective of this study was to collect normative data for the measurement of various cardiac structures using M-Mode and two-dimensional (2D) echo in healthy Indian neonates and to derive Z-scores for each measured parameter.

Methods

Echocardiograms were performed on healthy term neonates (within first 5 days of life). Birth weight and length were recorded, and body surface area was calculated using Haycock's formula. Twenty M-mode and 2D-echo parameters were measured (including left ventricular dimensions, atrioventricular valves, and semilunar valves' annuli sizes, pulmonary artery and branches, aortic root, and arch).

Results

We studied 142 neonates (73 males) with a mean age of 1.83 ± 1.12 days and mean birth weight of 2.89 ± 0.39 Kg. Regression equations with linear, logarithmic, exponential and square root models were tested to select the best model of fit for the relationship between birth weight and each echocardiographic parameter. Scatter plots and nomogram charts with Z-scores were prepared for each echocardiographic parameter.

Conclusions

Our study provides nomograms with Z-scores for term Indian neonates weighing between 2 kg and 4 kg at birth, within first 5 days of life, for a set of echocardiographic parameters that are frequently used in clinical practice. This nomogram has poor predictability for babies at extremes of birth weight. There is a need for further indigenous studies to include neonates at extremes of weight, both term, and preterm.

Proinflammatory and cardiovascular biomarkers are associated with echocardiographic abnormalities in children with HIV taking antiretroviral therapy

OBJECTIVES

Children with perinatally acquired HIV (PHIV) and taking antiretroviral therapy (ART) have a high prevalence of subclinical cardiac disease. We hypothesized that cardiac disease may be a consequence of dysregulated systemic immune activation driven by HIV infection. We examined cardiovascular and proinflammatory biomarkers and their association with echocardiographic abnormalities in children with PHIV.

DESIGN

Cross-sectional analysis of soluble biomarkers from a prospective cohort of children aged 6-16 years with PHIV and age-matched HIV-uninfected comparison group.

METHODS

Cryopreserved plasma samples were used to measure seven soluble biomarkers using multiplex bead assay (Luminex). Multivariable logistic regression assessed how biomarker levels related to cardiac abnormalities.

RESULTS

A total of 406 children participated in this study (195 PHIV and 211 HIV-uninfected). Mean [standard deviation (SD)] ages of PHIV and HIV-uninfected participants were 10.7 (2.6) and 10.8 (2.8) years, respectively. Plasma levels of CRP, TNF-α, ST2, VCAM-1 and GDF-15 were significantly higher in the PHIV group compared with uninfected control ( P  < 0.001). Among children with PHIV, with one-unit representing one SD in biomarker level, a one-unit increase in CRP and GDF-15, was associated with increased odds of having left ventricular (LV) diastolic dysfunction [adjusted odds ratio (aOR), 1.49 (1.02-2.18; P  < 0.040)] and [aOR 1.71 (1.18-2.53; P  = 0.006)], respectively. Each one unit increase in GDF-15 was associated with increased odds of LV hypertrophy [aOR 1.84 (95% CI 1.10-3.10; P  < 0.021)].

CONCLUSION

Children with PHIV had higher levels of proinflammatory and cardiovascular biomarkers compared with HIV-uninfected children. Increased CRP and GDF-15 were associated with cardiac abnormalities in children with PHIV.

Reference values and the Z-score values of tricuspid annular plane systolic excursion in Chinese children

To establish age-specific and body surface area (BSA)-specific reference values of Tricuspid Annular Plane Systolic Excursion (TAPSE) for children under 15 years old in China. A retrospective study was conducted in Children's Hospital Attached to the Capital Institute of Pediatrics. A total of 702 cases were included in this research to establish reference values of TAPSE in Chinese children. SPSS 25.0 (IBM) was used for data analysis. Lambda-mu-sigma method was used to calculate and construct the age-specific and BSA-specific percentiles and Z-score curves of TAPSE. The mean value of TAPSE increased with age and BSA from 0 to 15 years in a nonlinear way and reached the adult threshold (17 mm) until 1 year old. There was no difference between genders. TAPSE values increased with age and BSA in Chinese children aged between 0 and 15 years and there was no difference between boys and girls. A prospective, multicenter cohort study from different parts of China is supposed to be conducted in the future to reflect the whole spectrum of TAPSE in Chinese children.

Assessment of cardiac dimensions in children diagnosed with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant heart disease, characterized by increased left ventricular wall thickness and abnormal loading conditions. Imaging modalities are the first choice for diagnosis and risk stratification. Although heart dimensions have been characterized widely in HCM adults from cardiac imaging, there is limited information about children affected by HCM. The aim of this study is to evaluate left ventricular function and left heart dimensions in a small population of children diagnosed with HCM.

METHODS

A total of 16 (seven male, nine female) pediatric patients with an average age of 14.0 ± 2.5 years diagnosed with HCM at Great Ormond Street Hospital for Children were included in this study. Cardiac magnetic resonance (CMR) images were used to measure left and right ventricular dimensions, and septal and left ventricular free wall thicknesses in Simpleware ScanIP. The gender groups were compared using student t-test or non-parametric Mann-Whitney U-test depending on the sample distribution.

RESULTS

Differences in heart rate, left ventricular end-diastolic volume and end-diastolic volume index, left ventricular stroke volume and stroke volume index, left ventricular end-systolic long axis length, left ventricular end-systolic long axis length index, left ventricular end-diastolic mid-cavity diameter, left ventricular end-diastolic free wall thickness, left ventricular end-diastolic free wall thickness index, right ventricular end-diastolic long axis length were statistically significant in males and females.

CONCLUSION

Left ventricular wall and intraventricular septal thickness increase affecting left ventricle cavity dimensions and there may be differences in anatomical and physiological parameters in males and females affected by HCM.

The effect of azithromycin for management of HIV-associated chronic lung disease on right heart function: Results from the BREATHE trial

BACKGROUND

Right heart abnormalities and pulmonary hypertension (PH) may be secondary to chronic lung disease. Chronic lung disease is common in children with HIV. In the BREATHE trial ( Trial registration: NCT02426112), azithromycin (AZM) reduced the risk of acute respiratory exacerbations in children aged 6-19 years with HIV-associated chronic lung disease (HCLD) taking antiretroviral therapy. We assessed the possible effect of AZM on right heart dysfunction and/or PH in the trial.

METHODS

A standardised transthoracic echocardiogram using M-mode, two-dimensional and Doppler was performed, at baseline and at completion of weight-based AZM given weekly for 48 weeks. Linear regression was used to compare trial arms.

RESULTS

A total of 169 participants (82 AZM arm; 87 placebo arm) were included. Participants in the placebo arm were older, median age 16.2 (13.0-18.2) vs 15.3 (12.9-17.4) years, p = 0.184 in the AZM arm. At baseline, right heart abnormalities (right ventricular systolic dysfunction (RVSD), dilatation, or PH) were observed in 7(4%). Following treatment, there was no difference in prevalence of RVSD between arms (p = 0.761). There was one incident case of suspected PH, and overall, no difference in pulmonary pressures.

CONCLUSION

In children with HCLD, there was evidence of secondary cardiac effects, but AZM had no effect on right heart function. Long-term follow-up in children with HIV should be part of future research to understand the clinical implications of right heart abnormalities.

Reference values of electrographic and cardiac ultrasound parameters in Russian healthy children and adolescents

Between 2009 and 2013, a large cross-sectional study on the health consequences of the Chernobyl nuclear accident was performed in the contaminated and uncontaminated territories of the Bryansk Oblast (Russian Federation). The objective of this work was to confirm or refute a possible association between childhood cardiac arrhythmia and a chronic exposure to caesium-137. As part of this study, a large number of electrocardiographic and cardiac ultrasound parameters were collected from 18,152 children aged 2-18 years including 12,512 healthy ones not contaminated with caesium-137. It seemed therefore relevant for us to share in a second publication these medical data based on healthy and uncontaminated children with the scientific community because of the large quantities and the limited availability of such kind of data. In the present study, relating to electrocardiographic parameters, the measurements performed fully reflect the expected evolution of the paediatric electrocardiogram between 5 and 18 years of age. Thus, the median values were generally quite close to those available in the literature. In contrast, differences in the 2nd and 98th percentiles were notable and could be explained in particular by the type of equipment used, the number of subjects included in the study and racial disparities. As for echocardiographic parameters, the evolution of the measured values in age groups is consistent with what was expected considering factors such as growth. In comparison with other scientific studies that have investigated these echocardiographic parameters, some differences by age groups have been identified. The ethnic factor truly appears to be a relevant feature to consider. In view of the results, it appeared essential to the authors to approach the methodological conditions of the scientific studies already published on the topic to be truly comparable and thus to provide a reliable answer on a topic for which real expectations in terms of medical care are required.

Left ventricular mass normalization in child and adolescent athletes must account for sex differences

Background

To assess left ventricular hypertrophy, actual left ventricular mass (LVM) normalized for body size has to be compared to the LVM normative data. However, only some published normative echocardiographic data have been produced separately for girls and boys; numerous normative data for the pediatric population are not sex-specific. Thus, this study aimed to assess whether the LVM normative data should be developed separately for girls and boys practicing sports.

Methods

Left ventricular mass was computed for 331 girls and 490 boys, 5–19 years old, based on echocardiography. The effect of sex on the relationship between LVM and body size was evaluated using a linear regression model. Seven sets of the LVM normative data were developed, using different methodologies, to test concordance between sex-specific and non-specific normative data. Every set consisted of normative data that was sex-specific and non-specific. Upon these normative data, for every study participant, seven pairs of LVM z-scores were calculated based on her/his actual LVM. Each pair consisted of z-scores computed based on sex-specific and non-specific normative data from the same set.

Results

The regression lines fitted to the data points corresponding to LVM of boys had a higher slope than of girls, indicating that sex affects the relationship between LVM and body size. The mean differences between the paired LVM z-scores differed significantly from 0. The percentage of discordant indications, depending on the normalization method, ranged from 66.7% to 100% in girls and from 35.4% to 50% in boys. Application of the LVM normative data that were not sex-specific made relative LVM underestimated in girls and overestimated in boys.

Conclusion

The LVM normative data should be developed separately for girls and boys practicing sports. Application of normative data that are not sex-specific results in an underestimation of relative LVM in girls and overestimation in boys.

Lipid Biomarkers as Predictors of Diastolic Dysfunction in Diabetes with Poor Glycemic Control

Uncontrolled type-1 diabetes (T1DM) can lead to dyslipidaemia and albuminuria, which may promote cardiovascular injuries. However, some lipidemic factors could be useful in predicting cardiac dysfunction. Seventy-eight adolescents under insulin treatment due to a 6-year history of T1DM and were retrospectively examined. Glycemia, lipidemia, and albuminuria were measured in addition to development of cardiovascular abnormalities Both girls and boys showed higher HbA1c and fasting blood glucose and 27.1% females and 33.3% males exhibited microalbuminuria though their plasma levels of total cholesterol (TC), triglycerides (TG), and low-density lipoproteins (LDL) and high-density lipoproteins (HDL lipoproteins were in the normal range. They exhibited a preserved systolic function, but 50% of females and 66.6% of males had developed diastolic failures. Interestingly, girls with diastolic dysfunction showed significantly lower concentrations of HDL and higher TC/HDL and TG/HDL ratios. In fact, low HDL levels (OR 0.93; 95% CI 0.88-0.99; p = 0.029) and high TC/HDL (OR 2.55; 95% CI 1.9-5.45; p = 0.016) and TG/HDL (OR 2.74; 95% CI 1.12-6.71; p = 0.028) ratios associated with the development of diastolic complications. The cut-off values for HDL, TC/HDL, and TG/HDL were 49 mg/dL, 3.0 and 1.85, respectively. HDL and TC/HDL and TG/HDL ratios may be useful for predicting diastolic dysfunction in girls with uncontrolled T1DM.

Unexpectedly High Prevalence of Cytomegalovirus DNAemia in Older Children and Adolescents With Perinatally Acquired Human Immunodeficiency Virus Infection

Background

Older children and adolescents with perinatally acquired human immunodeficiency virus (PHIV) infection in Africa experience multiple comorbidities that are not typical of HIV-associated opportunistic infections, including growth impairment and chronic lung disease. We examined associations between plasma cytomegalovirus (CMV) DNA and lung function and growth.

Methods

Plasma CMV DNA loads were measured children aged 6–16 years with PHIV (n = 402) and HIV-uninfected controls (n = 224). The HIV-infected children were either newly diagnosed or known HIV infected and stable on antiretroviral therapy (ART) for >6 months. CMV DNA loads were measured using quantitative polymerase chain reaction. CMV DNAemia was modeled as a time-varying outcome using longitudinal mixed-effects logistic regression.

Results

At enrollment, CMV DNAemia ≥1000 copies/mL (defined as “clinically significant”) was detected in 5.8% of uninfected children, 14.7% of HIV-infected participants stable on ART, and 22.6% of HIV-infected ART-naive children (χ² = 23.8, P < .001). The prevalence of CMV DNAemia ≥1000 copies/mL was associated with CD4 counts <350 cells/µL. Among HIV-infected ART-naive children, the presence of CMV DNAemia of ≥1000 copies/mL was independently associated with reduced lung function (adjusted odds ratio [aOR] = 3.23; 95% confidence interval [CI], 1.23–8.46; P = .017). Among ART-treated children, stunting was associated with CMV DNAemia of ≥1000 copies/mL (aOR = 2.79; 95% CI, 0.97–8.02; P = .057).

Conclusions

Clinically significant levels of CMV DNAemia were common in older children with PHIV, even those on ART, suggesting a role for inadequately controlled CMV infection in the pathogenesis of PHIV comorbidities in Africa.

Incidence and Progression of Echocardiographic Abnormalities in Older Children with Human Immunodeficiency Virus and Adolescents Taking Antiretroviral Therapy: A Prospective Cohort Study

BACKGROUND

A high prevalence of cardiac abnormalities has been reported in children with human immunodeficiency virus (HIV) taking antiretroviral therapy (ART) in sub-Saharan Africa. We investigated the incidence and progression of cardiac abnormalities among children taking ART in Zimbabwe.

METHODS

A prospective cohort study was conducted at a pediatric HIV clinic from 2014 to 2017. Children with HIV aged between 6 and 16 years and taking ART ≥6 months were enrolled. Transthoracic echocardiography was performed at baseline and after 18 months.

RESULTS

Of 197 participants recruited at baseline, 175 (89%; 48% female; median age 12 years, interquartile range 10-14 years) were followed up. The incidences of left and right heart abnormalities were 3.52 and 5.64 per 100 person-years, respectively. Stunting was associated with the development of any cardiac abnormality (adjusted odds ratio 2.59, 95% confidence interval 1.03-6.49; P = .043). Right ventricular (RV) dilatation persisted at follow-up in 92% of participants and left ventricular (LV) diastolic dysfunction in 88%. Cardiac abnormalities present at baseline reverted to normal over the follow-up period in 11 (6%). There was an overall increase in mean z scores for LV, left atrium (LA), RV, interventricular septum, and LV posterior wall diameters at 18 months (P < .001).

CONCLUSIONS

Despite ART, children with HIV have a high incidence of cardiac abnormalities, with only a minority being transient. Mean z scores for LV, LA, RV, interventricular septum, and LV posterior wall diameters increased over a relatively short follow-up period, suggesting the potential for progression of cardiac abnormalities. Longer follow-up is required to understand the clinical implications of these abnormalities.

Mathematical modeling of cardiac function to evaluate clinical cases in adults and children

Time-varying elastance models can simulate only the pressure and volume signals in the heart chambers while the diagnosis of clinical cases and evaluation of different treatment techniques require more information. In this study, an extended model utilizing the geometric dimensions of the heart chambers was developed to describe the cardiac function. The new cardiac model was evaluated by simulating a healthy and dilated cardiomyopathy (DCM) condition for adults and children. The left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 53.60%, 125 mL, 5.08 cm and 1.82 in the healthy adult cardiovascular system model and 23.70%, 173 mL, 6.60 cm and 1.40 in the DCM adult cardiovascular system model. In the healthy child cardiovascular system model, the left ventricular ejection fraction, end-diastolic volume, end-diastolic diameter and diastolic sphericity index were 59.70%, 92 mL, 4.10 cm and 2.26 respectively and 30.70%, 125 mL, 4.94 cm and 1.87 in the DCM child cardiovascular system model. The developed cardiovascular system model simulates the hemodynamic variables and clinical diagnostic indicators within the physiological range for healthy and DCM conditions proving the feasibility of this new model to evaluate clinical cases in adults and children.

Left ventricular mass is underestimated in overweight children because of incorrect body size variable chosen for normalization

Background

Left ventricular mass normalization for body size is recommended, but a question remains: what is the best body size variable for this normalization—body surface area, height or lean body mass computed based on a predictive equation? Since body surface area and computed lean body mass are derivatives of body mass, normalizing for them may result in underestimation of left ventricular mass in overweight children. The aim of this study is to indicate which of the body size variables normalize left ventricular mass without underestimating it in overweight children.

Methods

Left ventricular mass assessed by echocardiography, height and body mass were collected for 464 healthy boys, 5–18 years old. Lean body mass and body surface area were calculated. Left ventricular mass z-scores computed based on reference data, developed for height, body surface area and lean body mass, were compared between overweight and non-overweight children. The next step was a comparison of paired samples of expected left ventricular mass, estimated for each normalizing variable based on two allometric equations—the first developed for overweight children, the second for children of normal body mass.

Results

The mean of left ventricular mass z-scores is higher in overweight children compared to non-overweight children for normative data based on height (0.36 vs. 0.00) and lower for normative data based on body surface area (-0.64 vs. 0.00). Left ventricular mass estimated normalizing for height, based on the equation for overweight children, is higher in overweight children (128.12 vs. 118.40); however, masses estimated normalizing for body surface area and lean body mass, based on equations for overweight children, are lower in overweight children (109.71 vs. 122.08 and 118.46 vs. 120.56, respectively).

Conclusion

Normalization for body surface area and for computed lean body mass, but not for height, underestimates left ventricular mass in overweight children.

Percentile curves for left ventricle structural, functional and haemodynamic parameters obtained in healthy children and adolescents from echocardiography-derived data

BACKGROUND

Transthoracic echocardiography is the most common non-invasive technique for the study of the left ventricle (LV) and the proximal aorta. Despite the clinical value, there is scarcity of data about reference intervals (RIs) and percentiles for thoracic aorta dimension and LV structural and functional parameters, obtained from population-based studies in children and adolescents. The aim was to generate RIs for LV, haemodynamic and thoracic aorta parameters obtained from transthoracic echocardiography in healthy children, adolescents and young adults from a South-American population.

METHODS

One thousand ninety-five healthy subjects (5-24 years) were studied (M-mode, B-mode and Doppler echocardiography).

RESULTS

RIs for LV structural (diameters, volumes and wall thickness) and functional (stroke volume, cardiac output, cardiac index, transmitral E and A flow waves velocities) parameters; systemic vascular resistance and aortic root diameter were obtained using parametric regression analyzes based on fractional polynomials. Covariate analysis (i.e., adjusting for age, body surface) showed that specific sex-specific RIs were necessary. Then, age, body height (BH), body weight (BW), body surface area (BSA), and sex-specific 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th and 99th percentiles were obtained. Our results were in agreement with and complimentary to available international databases.

CONCLUSION

This study provides RIs for echocardiography-derived haemodynamic, LV (structural and functional) and aortic parameters in children, adolescents and young adults considering data obtained from the largest Argentinean database. In early stages of life an adequate interpretation of echocardiography-derived LV and aortic parameters requires considering age, BH, BW, BSA and/or sex-specific RIs.

High prevalence of echocardiographic abnormalities in older HIV-infected children taking antiretroviral therapy

Background:

Antiretroviral therapy (ART) has decreased mortality so that increasing numbers of children with HIV are reaching adolescence. However, longstanding HIV infection and/or its treatment in children is associated with noninfectious complications including cardiac disease. We investigated the prevalence, spectrum and risk factors for echocardiographic abnormalities among children established on ART.

Methods:

HIV-infected children aged 6–16 years, on ART at least 6 months were enrolled into a cross-sectional study from a public-sector paediatric HIV clinic in Harare, Zimbabwe. A standardized examination including transthoracic echocardiography was performed. Local echocardiographic reference ranges were used to define cardiac abnormalities. Logistic regression was used to examine the association between cardiac abnormalities and risk factors.

Results:

Of the 201participants recruited, 92 (46%) were girls and median age was 11 (IQR 9–12) years; CD4⁺ cell count was 727 cells/μl (IQR 473–935) and 154 (78%) had viral load less than 400 copies/ml. Echocardiographic abnormalities were found in 83 (42%); left ventricular (LV) diastolic dysfunction was the most common abnormality 45 (23%) and LV hypertrophy in 22 (11%). LV and left atrial dilatation were found in 9 (5%) and 16 (8%), respectively. Right ventricular dilatation and systolic dysfunction were found in 13 (7%) and 4 (2%), respectively, of whom 60% had concurrent left heart abnormalities. Current use of nevirapine was associated with LVH [aOR 3.14 (1.13–8.72; P = 0.03)] and hypertension was associated with LV diastolic dysfunction [aOR 3.12 (1.48–6.57; P < 0.01)].

Conclusion:

HIV-infected children established on ART have a high burden of echocardiographic abnormalities. Right heart disease was predominantly associated with left heart abnormalities and may be part of a global cardiomyopathic process. Further studies are needed to investigate the natural history, aetiology, and pathogenesis of these abnormalities, so that appropriate monitoring and treatment strategies can be developed.

Racial Variation in Echocardiographic Reference Ranges for Left Chamber Dimensions in Children and Adolescents: A Systematic Review

Echocardiography plays a critical role in the assessment of cardiac disease. Important differences in echocardiographically derived cardiac chamber dimensions have been previously highlighted in different population groups in adult studies, but this has not been systematically studied in children, whose body size changes throughout childhood. The aim of this study was to review the distribution of available reference ranges for the left cardiac chamber dimensions in older children and adolescents. The following electronic data bases were searched: Medline, Embase and Web of Science were searched to identify studies which have established echocardiographic reference ranges of left heart parameters in children and adolescents from 1975 to December 2017. There was no geographical limitation. All results were imported into Endnote. Retrieved articles were screened and data extracted by two independent reviewers. A total of 4398 studies were retrieved, with 36 studies finally included in this review. 29 (81%) references were from North America and European (Caucasians) populations, with only one study each from Africa and South America. Two-dimensional and M-mode techniques were the most commonly used echocardiography techniques. There were methodological variations in techniques and normalisation of references. Comparison of selected cardiac measures showed significant differences for interventricular septal thickness among Black African, Indian, German and US American children. Available echocardiographic references cannot be generalised to all settings and therefore, there is need for locally relevant reference ranges. Africa and South America are particularly under-represented. Future studies should focus on developing comprehensive echocardiographic reference ranges for children from different racial backgrounds and should use standardised techniques.