Normal Values for Left Ventricular Mass in Relation to Lean Body Mass in Child and Adolescent Athletes

Cardiovascular health and potential cardiovascular risk factors in young athletes

Introduction

Cardiovascular disease remains the most common cause of death worldwide, and early manifestations are increasingly identified in childhood and adolescence. With physical inactivity being the most prevalent modifiable risk factor, the risk for cardiovascular disease is deemed low in people engaging in regular physical exercise. The aim of this study was to investigate early markers and drivers of cardiovascular disease in young athletes pursuing a career in competitive sports.

Methods

One hundred and five athletes (65 males, mean age 15.7 ± 3.7 years) were characterized by measurement of body impedance to estimate body fat, blood pressure (BP), carotid femoral pulse wave velocity (PWV) to evaluate arterial elasticity, ergometry to assess peak power output, echocardiography to calculate left ventricular mass, and blood tests.

Results

Systolic BP was elevated in 12.6% and thereby more than twice as high as expected for the normal population. Similarly, structural vascular and cardiac changes represented by elevated PWV and left ventricular mass were found in 9.5% and 10.3%. Higher PWV was independently associated with higher systolic BP (β = 0.0186, p < 0.0001), which in turn was closely correlated to hemoglobin levels (β = 0.1252, p = 0.0435). In this population, increased left ventricular mass was associated with lower resting heart rate (β = -0.5187, p = 0.0052), higher metabolic equivalent hours (β = 0.1303, p = 0.0002), sport disciplines with high dynamic component (β = 17.45, p = 0.0009), and also higher systolic BP (β = 0.4715, p = 0.0354).

Conclusion

Despite regular physical exercise and in the absence of obesity, we found an unexpected high rate of cardiovascular risk factors. The association of PWV, systolic BP, and hemoglobin suggested a possible link between training-induced raised hemoglobin levels and altered vascular properties. Our results point toward the need for thorough medical examinations in this seemingly healthy cohort of children and young adults. Long-term follow-up of individuals who started excessive physical exercise at a young age seems warranted to further explore the potential adverse effects on vascular health.

Insights into the Cardiac Phenotype in 9p Deletion Syndrome: A Multicenter Italian Experience and Literature Review

Chromosome 9p deletion syndrome is a rare autosomal dominant disorder presenting with a broad spectrum of clinical features, including congenital heart defects (CHDs). To date, studies focused on a deep characterization of cardiac phenotype and function associated with this condition are lacking. We conducted a multicentric prospective observational study on a cohort of 10 patients with a molecular diagnosis of 9p deletion syndrome, providing a complete cardiological assessment through conventional echocardiography and tissue Doppler imaging echo modality. As a result, we were able to demonstrate that patients with 9p deletion syndrome without major CHDs may display subclinical cardiac structural changes and left-ventricle systolic and diastolic dysfunction. Albeit needing validation in a larger cohort, our findings support the idea that a complete cardiac assessment should be performed in patients with 9p deletion syndrome and should be integrated in the context of a long-term follow-up.

Athlete Heart in Children and Young Athletes. Echocardiographic Findings in 331 Cases

The changes of the athlete's heart are not well defined and characterized in children. We aimed to describe the morphological changes of the heart related to sport in young athletes. We evaluated a group of 331 young athletes under 18 years (mean 11.9 ± 3.2) who practice tennis: 58 (16.52%), football: 118 (33.62%), basketball: 16 (4.56%), athletics: 40 (11.4%), and swimming: 99 (28.21%). Type of sport, years of practice, and duration of the training were collected. All children underwent echocardiography with the following M-mode parameters: left atrium diameter (LAD), interventricular septum (IVS), and left ventricle posterior Wall (LVPW), diastolic diameter of the left ventricle (LVDD), and right ventricle outflow tract (RVOT). The major finding of our study was that 20% of the children had a Z score > 2 for the IVS and that increased to 30% for the children playing tennis or swimming. Also, other changes like LA and RVOT dilatation were observed in about 10 and 14% of the cases, respectively. Taken together, these figures indicate that cardiac remodeling is frequent in children. Further studies are needed to establish consensus-based criteria of athlete's heart in young children.

Influencing Factors of Cardiac Adaptation in Adolescent Athletes

Endurance training-induced changes in left ventricular diastolic function and right ventricular parameters have been investigated extensively in adolescent athletes. Our aim was to examine the parameters for adolescent athletes (n=121, 15.1±1.6 years) compared to adult athletes and age-matched non-athletes. We explored the effects of influencing factors on the echocardiographic parameters. Significantly higher E/A (p<0.05) and e' values (p<0.001) were detected in adolescent athletes compared to age-matched non-athletes' and also adult athletes' parameters. Significantly lower structural and functional right ventricular parameters (p<0.05) were detected in adult athletes. In adolescent athletes significantly higher right ventricular diameters, tricuspid S wave, right ventricular end-diastolic and end-systolic area values (p<0.05) were found compared to the matching parameters of non-athletes. We found significantly higher corrected tricuspid annular plane systolic excursion values (p<0.001) in athletes compared to the non-athletes. Based on multivariate analysis lean body mass, body surface area, age and cumulative training time were proved as strong predictive factors of both left ventricular diastolic and right ventricular parameters. Supernormal left ventricular diastolic function and significantly higher right ventricular parameters are indicative of cardiac adaptation. Well-defined cut-off values should be applied to discriminate pathological conditions in the relation of the influencing factors.

Donor and Recipient Size Matching in Heart Transplantation With Predicted Heart and Lean Body Mass

Donor and recipient size matching during heart transplant can be assessed using weight or predicted heart mass (PHM) ratios. We developed sex-specific allomteric equations for PHM and predicted lean body mass (PLBM) using the United Kingdom Biobank (UKB) and evaluated their predictive value in the United Network of Organ Sharing database. Donor and recipient size matching was based on weight, PHM and PLBM ratios. PHM was calculated using the Multiethnic Study of Atherosclerosis and UKB equations. PLBM was calculated using the UKB and National Health and Nutrition Examination Survey equations. Relative prognostic utility was compared using multivariable Cox analysis, adjusted for predictors of 1-year survival in the Scientific Registry of Transplant Recipients model. Of 53,648 adult patients in the United Network of Organ Sharing database between 1996 and 2016, 6528 (12.2%) died within the first year. In multivariable analysis, undersized matches by any metric were associated with increased 1-year mortality (all P < 0.01). Oversized matches were at increased risk using PHM or PLBM (all P < 0.01), but not weight ratio. There were significant differences in classification of size matching by weight or PHM in sex-mismatched donor-recipient pairs. A significant interaction was observed between pulmonary hypertension and donor undersizing (hazard ratio 1.15, P = 0.026) suggesting increased risk of undersizing in pulmonary hypertension. Donor and recipient size matching with simplified PHM and PLBM offered an advantage over total body weight and may be more important for sex-mismatched donor-recipient pairs. Donor undersizing is associated with worse outcomes in patients with pulmonary hypertension.

Assessment of Structure, Function, and Rhythm of the Heart with Echocardiography and Electrocardiography in Adolescent Swimmers

The aim of this study was to evaluate the cardiac parameters by using electrocardiography and echocardiography in adolescent swimmers. Twenty-two adolescent swimmers and 22 gender- and age-matched sedentary controls admitted to our center between November 2018 and May 2019 were included in this study. In addition to demographical characteristics, participants were assessed via a 12-lead electrocardiography and two-dimensional echocardiography for cardiac function. On the echocardiography, end-systolic and end-diastolic interventricular septum, end-systolic and end-diastolic left ventricular posterior wall thicknesses, left atrial width, Tricuspid E, left ventricular mass and left ventricular mass index were higher in the swimmers when compared to the sedentary controls (P < 0.05). On the electrocardiography, Tp-e duration which reflects ventricular transmural repolarization, and Tp-e/QT and Tp-e/corrected QT ratios were higher in the swimmers than the sedentary controls (P < 0.05). In conclusion, swimming exercise in children leads to concentric thickening of left ventricle and induces an increase in Tp-e duration, and Tp-e/QT and Tp-e/corrected QT ratios, which are the novel markers for risk of ventricular arrhythmias.

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.

Carotid Intima-Media Thickness but Not Carotid Artery Plaque in Healthy Individuals Is Linked to Lean Body Mass

Background Lean body mass has been identified as a key determinant of left ventricular mass and wall thickness. However, the importance of lean body mass or other body-size measures as normative determinants of carotid intima-media thickness (cIMT), a widely used early indicator of atherosclerosis, has not been well established. Methods and Results Carotid artery ultrasound measurements of cIMT and carotid artery plaque burden (derived from plaque number and maximum size) and measurements of body size, including height, body mass index, weight, body fat proportion, and lean body mass ([1-body fat proportion]×weight), were recorded in 25 020 participants from 10 regions of China. Analyses were restricted to a healthy younger subset (n=6617) defined as never or long-term ex-regular smokers aged <60 years (mean age, 50) without previous ischemic heart disease, stroke, diabetes mellitus, or hypertension and with plasma non-high-density lipoprotein cholesterol <4 mmol/L. Among these 6617 participants, 86% were women (because most men smoked) and 9% had carotid artery plaque. In both women and men separately, lean body mass was strongly positively associated with cIMT, but was not associated with plaque burden: overall, each 10 kg higher lean body mass was associated with a 0.03 (95% CI, 0.03-0.04) mm higher cIMT (P=5×10-33). Fat mass, height, and other body-size measures were more weakly associated with cIMT. Conclusions The strong association of lean body mass with cIMT, but not with plaque burden, in healthy adults suggests a normative relationship rather than reflecting atherosclerotic pathology. Common mechanisms may underlie the associations of lean body mass with cIMT and with nonatherosclerotic vascular traits.

Normal basic 2D echocardiographic values to screen and follow up the athlete's heart from juniors to adults: What is known and what is missing. A critical review

In the last few years, multiple echocardiographic nomograms have been published. However, normal values calculated in the general population are not applicable to athletes, whose hearts may be enlarged and hypercontractile. Accordingly, athletes require specific nomograms. Our aim is to provide a critical review of echocardiographic nomograms on two-dimensional (2D) measures for athletes. We performed a systematic search in the National Library of Medicine for Medical Subject Headings and free text terms including echocardiography, athletes, normal values and nomograms. The search was refined by adding the keywords heart, sport, elite, master, children and young. Twenty-eight studies were selected for the final analysis. Our research revealed that currently available ranges of normality for athletes reported by different authors are quite consistent, with limited exceptions (e.g. atria, aorta). Numerical and methodological limitations, however, emerged. Numerical limitations included a limited sample size (e.g. < 450 subjects) of the population assessed and the paucity of data in women, non-Caucasian athletes, and junior and master athletes. Some data on M-mode measurements are available, while those for some specific structures (e.g. left atrial (LA) area and volumes, right ventricular diameters and aorta) are limited or rare (e.g. LA area). There was heterogeneity in data normalization (by gender, sport type and ethnicity) and their expression was limited to mean values (Z-scores have rarely been employed), while variability analysis was often lacking or incomplete. We conclude that comprehensive nomograms using an appropriate sample size, evaluating a complete dataset of 2D (and three-dimensional) measures and built using a rigorous statistical approach are warranted.