Echocardiographic Normal Reference Ranges for Non-invasive Myocardial Work Parameters in Pediatric Age: Results From an International Multi-Center Study

Echocardiographic reference ranges of myocardial work in children and adolescents: A meta-analysis

BACKGROUND

Establishing reference values for LV myocardial work (MW) is essential before its widespread implementation in pediatrics. This study aims to provide normal LV MW ranges, encompassing global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE).

METHODS

Databases were searched through February 1st, 2024, for studies reporting MW indices in healthy children across pediatric age categories. Weighted means were obtained from random-effect models with corresponding 95 % confidence intervals (CI). Subgroup analyses were conducted to identify sex or geographic differences. Meta-regression analysis was used to identify modulating effects of demographic, clinical, and echocardiographic variables.

RESULTS

The search yielded 104 articles, of which, 12 articles with 1037 patients (age 10.7 ± 0.7 years, 47.5 % female) were eligible for inclusion. The reported normal overall pooled mean values of GWI and GCW were 1525.4 (95 % CI, 1328.1-1722.6) mmHg% and 1880.3 (95 % CI, 1683.6-2077.0) mmHg%, respectively. Pooled mean GWW was 57.2 (95 % CI, 51.9-62.5) mmHg%, and pooled mean GWE was 96.8 (95 % CI, 96.6-97.0) %. Subgroup analysis found no sex differences (P > 0.050), but significant regional variations: GCW and GWW differed in European or US cohorts versus East Asian cohorts (P = 0.033 and P = 0.039, respectively). Meta-regression identified age, blood pressure, and heart rate as significant modulators. Pooled inter-observer intraclass correlation coefficients (ICCs) ranged from 0.86 to 0.96, while pooled intra-observer ICCs ranged from 0.81 to 0.93, indicating excellent reproducibility.

CONCLUSIONS

We provide age-specific MW reference ranges for children, valuable for both clinical and research purposes, and confirm the reproducibility of MW.

Cardiovascular function shows early impairment in asymptomatic adolescents diagnosed with type 1 diabetes mellitus: an ultrasound-derived myocardial work study

Background

Cardiac dysfunction and endothelial damage are known complications of type 1 diabetes mellitus (T1D) mainly affecting adults. However, some studies have shown that subclinical myocardial impairment already present during adolescence. Myocardial work (MW) has emerged as an afterload-independent tool that allows early identification of subclinical damage. This study aims to provide a comprehensive non-invasive cardiovascular evaluation of T1D adolescents using both conventional and advanced echocardiography.

Methods

We enrolled 31 patients, aged between 13 and 19 years, who were diagnosed with T1D for at least 10 years and were followed up by the Paediatric Diabetology Unit of our institution. We collected data relating to anthropometry, lifestyle, blood tests, glycemic control parameters, and conventional and advanced echocardiographic measurements. A comparison of MW parameters with the data from 31 age- and sex-matched healthy volunteers from a previous study in our lab was carried out.

Results

In our population, the glycemic control parameters showed suboptimal control. While diastolic parameters were in the normal range for all the patients, E' velocities and left atrial diameter were significantly worse in patients with poorer glycemic controls. Global longitudinal strain (GLS), global work index (GWI), and global work efficiency (GWE) were significantly lower in the T1D population compared to those in the healthy population (p < 0.001), while global wasted work was significantly higher in the T1D population (p < 0.001). Patients with stage 1 hypertension or a pre-hypertensive state exhibited pathological pulse wave velocities with values exceeding 8 m/s (>99th percentile).

Conclusions

To the best of our knowledge, this was the first study to investigate MW in T1D adolescents. The descriptive parameters of GLS and MW showed subclinical cardiac damage already during this timeframe. Therefore, these tools should be integrated into the cardiovascular assessment of diabetic adolescents, and preventive strategies should be implemented to maximize glycemic and pressure control effectiveness.

Noninvasive Assessment of Myocardial Work in Children

The noninvasive assessment of ventricular function is an ongoing challenge, with new tools and measurements always being considered and tested. The noninvasive assessment of myocardial work via the pressure-strain relationship is one of the newer tools proposed to evaluate ventricular systolic function. However, prior to using any new tool, one should understand its properties, utility, and limitations. In this commentary we focus on the noninvasive assessment of myocardial work via the pressure-strain relationship from a pediatric point of view. We address the current knowledge and limitations and propose future directions to better understand this tool.

Normal Values for Echocardiographic Myocardial Work in a Large Pediatric Population

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.

Myocardial work in children with Wolff-Parkinson-White syndrome

Wolff-Parkinson-White Syndrome (WPW) has been associated with reduced local myocardial deformation, and when left ventricular dysfunction is present, catheter ablation of the accessory pathway may be required, even in asymptomatic patients. We aimed to evaluate the diagnostic value of non-invasive myocardial work in predicting subtle abnormalities in myocardial performance in children with WPW.Seventy-five paediatric patients (age 8.7 ± 3.5 years) were retrospectively recruited for the study: 25 cases with manifest WPW and 50 age- and sex- matched controls (CTR). Global myocardial work index (MWI) was measured as the area of the left ventricle (LV) pressure-strain loops. From MWI, global Myocardial Constructive Work (MCW), Wasted Work (MWW), and Work Efficiency (MWE) were estimated. In addition, standard echocardiographic parameters of LV function were evaluated. Despite normal LV ejection fraction (EF) and global longitudinal strain (GLS), children with WPW had worse MWI, MCW, MWW, and MWE. At multivariate analysis, MWI and MCW were associated with GLS and systolic blood pressure, and QRS was the best independent predictor of low MWE and MWW. In particular, a QRS > 110 ms showed good sensitivity and specificity for worse MWE and MWW values. In children with WPW, myocardial work indices were found significantly reduced, even in the presence of normal LV EF and GLS. This study supports the systematic use of myocardial work during the follow-up of paediatric patients with WPW. Myocardial work analysis may represent a sensitive measure of LV performance and aid in decision-making.

The Role of Multimodality Imaging in Pediatric Cardiomyopathies

Cardiomyopathies are a heterogeneous group of myocardial diseases representing the first cause of heart transplantation in children. Diagnosing and classifying the different phenotypes can be challenging, particularly in this age group, where cardiomyopathies are often overlooked until the onset of severe symptoms. Cardiovascular imaging is crucial in the diagnostic pathway, from screening to classification and follow-up assessment. Several imaging modalities have been proven to be helpful in this field, with echocardiography undoubtedly representing the first imaging approach due to its low cost, lack of radiation, and wide availability. However, particularly in this clinical context, echocardiography may not be able to differentiate from cardiomyopathies with similar phenotypes and is often complemented with cardiovascular magnetic resonance. The latter allows a radiation-free differentiation between different phenotypes with unique myocardial tissue characterization, thus identifying the presence and extent of myocardial fibrosis. Nuclear imaging and computed tomography have a complementary role, although they are less used in daily clinical practice due to the concern related to the use of radiation in pediatric patients. However, these modalities may have some advantages in evaluating children with cardiomyopathies. This paper aims to review the strengths and limitations of each imaging modality in evaluating pediatric patients with suspected or known cardiomyopathies.

Normal ranges of non-invasive left ventricular myocardial work indices in healthy young people

OBJECTIVES

Echocardiographic global myocardial work (GMW) indices recently emerged to non-invasively evaluate left ventricular (LV) myocardial performance with less load-dependence than LV ejection fraction (LVEF) or global longitudinal strain (GLS). Yet, few data exist on the descriptions of LV GMW indices in young people. We therefore aimed to provide normal reference values of LV GMW in a healthy young cohort, and simultaneously to investigate factors associated with non-invasive GMW indices.

MATERIALS AND METHODS

A total of 155 healthy young people (age 10-24 years, 59% male) underwent transthoracic echocardiography were recruited and further stratified for age groups and divided by gender. Two-dimensional speckle-tracking echocardiography (2D-STE) were performed to determine LV GLS, peak strain dispersion (PSD) and GMW indices, which include global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). LV peak systolic pressure was assumed to be equal to the systolic brachial artery cuff blood pressure.

RESULTS

Age and gender specific normal ranges for LV GMW indices were presented. On multivariable analysis, GWI and GCW correlated more closely with systolic blood pressure (SBP) than LV GLS, while both GWW and GWE independently correlated with PSD (P < 0.05 for all). There were no associations between any of the GMW indices with age, sex, body mass index, heart rate, left ventricular mass index as well as LV sizes or LVEF. Of noted, LV GMW indices had good intra-observer and inter-observer reproducibility.

CONCLUSION

We reported echocardiographic reference ranges for non-invasive LV GMW indices in a large group of healthy young subjects, which are reproducible and reliable, and thus can be further used when assessing subclinical dysfunction in young people with myocardial diseases.