Daniele Chirico

Left ventricular structure and function in children with and without developmental coordination disorder

Children with developmental coordination disorder (DCD) are more likely to develop cardiovascular disease risk factors such as obesity and reduced cardio-respiratory fitness. However, there is limited data using laboratory measures for assessing the risk of cardiovascular disease associated with DCD. The purpose of this study was to examine differences in left ventricular structure and function between children with DCD and healthy controls. The study involved 126 children (aged 12-13 years) with significant motor impairment (n = 63) and healthy controls (n = 63) matched for age, sex, and school. The Movement ABC test (M-ABC2) was used to classify children as probable DCD (p-DCD). Cardiac dimensions were measured using ultrasound echocardiography. Left ventricular mass (LVM) was elevated in children with p-DCD (89 ± 17 g) compared to controls (87 ± 21 g), however, this difference was not significant. When LVM was normalized to height(2.7), no difference was evident between groups (26 g and 26 g for the p-DCD and controls, respectively). However, the p-DCD group demonstrated significantly elevated stroke volume (p = 0.02), cardiac output (p<0.001), end-diastolic volume (p = 0.03), and left ventricle diameter in diastole (p = 0.02). Also, peak VO(2) normalized for fat free mass (FFM) was significantly lower (p = 0.001) and systolic blood pressure (p = 0.01), body mass index (p = 0.001), heart rate (p = 0.005) and percent body fat (p<0.001) were significantly higher in p-DCD. In regression analyses, p-DCD was a significant predictor of stroke volume and cardiac output even after accounting for height, FFM, VO(2FFM), and sex. Children with p-DCD do not demonstrate significantly elevated LVM or depressed systolic function compared to healthy controls. However, cases with p-DCD demonstrate significantly elevated end-diastolic volume, diastolic chamber size, stroke volume, and cardiac output. These differences indicate obesity related changes in the left ventricle and may represent the early stages of developing left ventricle hypertrophy.

Longitudinal Assessment of Left Ventricular Structure and Function in Adolescents with Developmental Coordination Disorder.

Children with developmental coordination disorder (DCD) are more likely to develop cardiovascular disease (CVD) risk factors such as obesity and reduced cardio-respiratory fitness. It has also been shown that adolescents with probable DCD (p-DCD) have elevated cardiac output (CO) and stroke volume (SV) compared to typically developing (TD) controls, which in turn may heighten their risk of developing elevated left ventricle mass (LVM) or left ventricular hypertrophy (LVH). The purpose of this study was to assess left ventricular structure and function longitudinally in adolescents with and without p-DCD. This three year study included 86 adolescents with significant motor impairment (33) and TD controls (53). Adolescents were 12 years old at the beginning of the study. The Movement ABC test (M-ABC-2) was used to classify children as p-DCD. Cardiac dimensions were measured using ultrasound echocardiography. Body mass, fat mass (FM) and body mass index (BMI) were significantly elevated in the p-DCD group in all three years. Peak aerobic fitness normalized to fat-free mass (peak VO(2FFM)) was significantly elevated in the TD controls in each year. Heart rate was also increased in the p-DCD group in years one and three. A repeated measures ANCOVA with time-varying covariates was performed for CO and LVM on p-DCD while controlling for peak VO(2) and FFM. CO and LVM were significantly elevated in the p-DCD which remained constant over time. FM completely mediated the association between p-DCD and CO in adolescents. For LVM, both FM and CO accounted for elevated LVM in adolescents with p-DCD. In conclusion, elevated FM in adolescents with p-DCD contributes to a higher CO and LVM over time compared to TD controls. If this persists throughout adolescents and into adulthood, these adolescents may be at risk of developing LVH.

Baroreflex Sensitivity Is Reduced in Adolescents with Probable Developmental Coordination Disorder.

Developmental coordination disorder (DCD) is a neurodevelopmental condition characterized by poor motor skills leading to a significant impairment in activities of daily living. Compared to typically developing children, those with DCD are less fit and physically active, and have increased body fat. This is an important consequence as both sedentary lifestyle and obesity are risk factors for cardiovascular disease. One indicator of cardiovascular health is baroreflex sensitivity (BRS), which is a measure of short term blood pressure (BP) regulation and is partly accomplished through changes in heart rate. Diminished BRS is predictive of future cardiovascular morbidity and mortality. The purpose of this study was to compare BRS in typically developing (TD) adolescents with probable DCD (pDCD) or suspect pDCD (spDCD) adolescents (13-14 years of age). Percentile scores on the Movement Assessment Battery for Children, 2nd edition, assessed at two time points were averaged and used to classify participants into the following groups: pDCD ≤ 5th percentile, spDCD > 5th percentile and ≤16th percentile and TD>16th percentile. Following 15 min of supine rest, 5 min of continuous beat-by-beat blood pressure (Finapres) and R-R interval were recorded (standard ECG). Spectral indices were computed using Fast Fourier Transform with transfer function analysis used to compute BRS in the low frequency region (0.04-0.15 Hz). BRS was compared between groups with an ANOVA and post hoc Bonferroni correction. BRS was reduced in the pDCD compared to the TD groups. In multivariate regression analyses predicting BRS, when pDCD and spDCD were entered as the only variables, pDCD was found to be a significant predictor of BRS (b=-6.74, p=0.016). However, when sex, VO(2) peak, and percent body fat (PBF) were entered as covariates, pDCD was no longer a predictor, while PBF approached significance (-0.32, p=0.056). Therefore, in this sample, BRS was reduced in adolescents with pDCD principally due to increased PBF.

Linking systemic arterial stiffness among adolescents to adverse childhood experiences.

Adverse childhood experiences (ACEs) have been linked with cardiovascular disease and early mortality among adults. Most research examines this relationship retrospectively. Examining the association between ACEs and childrens cardiovascular health is required to understand the time course of this association. We examined the relationship between ACEs exposure and ECG-to-toe pulse wave velocity (PWV), a measure of systemic arterial stiffness that is strongly related to cardiovascular mortality among adults. PWV (distance/transit time; m/s) was calculated using transit times from the ECG R-wave to the pulse wave contour at the toe. Transit times were collected over 15 heartbeats and the distance from the sternal notch to the left middle toe was used. A total of 221 children (119 females) aged 10-14 years participated in data collection of PWV, hemodynamic and anthropometric variables. Parents of these children completed a modified inventory of ACEs taken from the Childhood Trust Events Survey. Multivariable regression assessed the relationship between ACEs group (<4 ACEs versus ≥4 ACEs) and PWV. Analyses yielded an ACEs group by sex interaction, with males who experienced four or more ACEs having higher PWV (p<0.01). This association was independent of hemodynamic, anthropometric and sociodemographic variables (R(2)=0.346; p<0.01). Four or more ACEs is associated with greater arterial stiffness in male children aged 10-14 years. Addressing stress and trauma exposure in childhood is an important target for public health interventions to reduce early cardiovascular risk.

Role of aortic arch vascular mechanics in cardiovagal baroreflex sensitivity.

Cardiovagal baroreflex sensitivity (cvBRS) measures the efficiency of the cardiovagal baroreflex to modulate heart rate in response to increases or decreases in systolic blood pressure (SBP). Given that baroreceptors are located in the walls of the carotid sinuses (CS) and aortic arch (AA), the arterial mechanics of these sites are important contributors to cvBRS. However, the relative contribution of CS and AA mechanics to cvBRS remains unclear. This study employed sex differences as a model to test the hypothesis that differences in cvBRS between groups would be explained by the vascular mechanics of the AA but not the CS. Thirty-six young, healthy, normotensive individuals (18 females; 24 ± 2 yr) were recruited. cvBRS was measured using transfer function analysis of the low-frequency region (0.04-0.15 Hz). Ultrasonography was performed at the CS and AA to obtain arterial diameters for the measurement of distensibility. Local pulse pressure (PP) was taken at the CS using a hand-held tonometer, whereas AA PP was estimated using a transfer function of brachial PP. Both cvBRS (25 ± 11 vs. 19 ± 7 ms/mmHg, P = 0.04) and AA distensibility (16.5 ± 6.0 vs. 10.5 ± 3.8 mmHg(-1) × 10(-3), P = 0.02) were greater in females than males. Sex differences in cvBRS were eliminated after controlling for AA distensibility (P = 0.19). There were no sex differences in CS distensibility (5.32 ± 2.3 vs. 4.63 ± 1.3 mmHg(-1) × 10(-3), P = 0.32). The present data demonstrate that AA mechanics are an important contributor to differences in cvBRS.

The Effects of Sex and Pubertal Maturation on Cardiovagal Baroreflex Sensitivity

OBJECTIVE To examine baroreflex sensitivity (BRS) across different stages of pubertal maturation in healthy children and adolescents. STUDY DESIGN This study was cross-sectional and included 104 participants (53 males and 51 females) aged 8-18 years old. Participants were organized into 5 pubertal groups based on the criteria of Tanner; prepubertal (Tanner 1, n = 19), early-pubertal (Tanner 2, n = 16), peripubertal (Tanner 3, n = 24), late-pubertal (Tanner 4, n = 23), and postpubertal (Tanner 5 and 6, n = 22). Adiposity (fat-free mass, fat mass, and body fat%), body mass index, and demographic variables were collected. Beat-by-beat blood pressure and R-R interval were collected during supine rest to determine BRS. BRS was assessed by transfer function analysis in the low frequency range (0.05-0.15 Hz). RESULTS The results demonstrated a sex-by-maturation interaction [F(4, 94) = 3.202, P = .019]. BRS decreased from early-to postpuberty in males (30 [7.1] vs 13.2 [7.8] ms/mm Hg), and remained unchanged in females. This led to significantly greater BRS in females compared with males, postpuberty (27 [7.3] vs 13.2 [7.8] ms/mm Hg). CONCLUSIONS Controlling for both sex and maturation when examining BRS in children and adolescents with cardiovascular disease risk factors will aid in interpreting abnormally high or low BRS values.

Evidence of a hyperkinetic state in children with elevated blood pressure

Abstract Background: Left ventricular hypertrophy (LVH) and elevated left ventricular mass index (LVMI) are important predictors of cardiovascular morbidity and mortality in adults. Children with hypertension and pre-hypertension demonstrate LVH and greater LVMI compared to normotensive children. The impact of blood pressure (BP) on early changes in left ventricular properties provides an opportunity to understand and identify cardiovascular risk early in childhood. Aim: The aim of this study was to assess left ventricular structural and functional properties in a sample of children across a wide range of BP values. Subjects and methods: Children aged 11–14-years were divided into BP groups: hypertensives (HTN; ≥95th percentile; n = 21) and normotensives (NTN; <90th percentile; n = 85) based on BP measures taken at two time points. Resting supine heart rate (HR), cardiac output (CO) and total peripheral resistance (TPR) were collected along with left ventricular structural and functional properties using ultrasound sonography. Results: LVMI and TPR were not different between groups. CO, HR and left ventricular end-diastolic and end-systolic volumes were elevated in the HTN group. Furthermore, HR and body mass index were found to be independent predictors of BP group status in children. Conclusion: These findings show that children with elevated BP are characterized by high HR and CO and normal TPR. Also, the results identify HR as a predictor of BP group status in early childhood.

Are Canadian-born Major League Baseball players more likely to bat left-handed? A partial test of the hockey-influence on batting hypothesis.

It has been suggested that Canadian-born Major League Baseball (MLB) players are more likely to bat left-handed, possibly owing to the fact that they learn to play ice hockey before baseball, and that there is no clear hand-preference when shooting with a hockey stick; approximately half of all ice hockey players shoot left. We constructed a database on active (i.e., October, 2016) MLB players from four countries/regions based on place of birth (Canada, United States of America [USA], Dominican Republic and South Asia [i.e., Japan, Taiwan and South Korea]), including information on which hand they use to bat and throw. We also extracted information on all Canadian-born MLB players, dating back to 1917. Our results confirm that the proportion of left-handed batters born in Canada is higher when compared to the other countries selected; also, since 1917, the proportion of Canadian MLB players who bat left has been consistently higher than the league average. We also compared the proportion of left-handed batters in Canada with players born in states in the USA grouped into high, average and low based on hockey participation. The proportion of MLB players born in states with a high level of hockey participation were more likely to bat left, although the differences were significant at trend level only (p < .10). Lastly, we found that while Canadians were more likely to bat left-handed, this did not correspond with a greater left-hand dominance, as determined by throwing hand. In conclusion, the present study confirms that Canadian-born MLB players are more likely to bat left-handed when compared to American, Dominican Republic and South Asian-born MLB players, providing partial support for the hockey influence on batting hypothesis.