title: THE EFFECT OF PHYSICAL GROWTH, BIOLOGICAL MATURATION AND ETHNICITY ON CARDIAC PRE-PARTICIPATION SCREENING IN MALE PAEDIATRIC ATHLETES
Creators: name: McClean, G
Publisher: name: Liverpool John Moores University
Year: 2021

description: Cardiac screening of the paediatric athlete is now recommended by many international sporting governing bodies and aims to identify those at risk of sudden cardiac death/arrest (SCD/A) from an undiagnosed cardiac condition. Regular and sustained physical activity is associated with a number of electrophysiological, structural and functional cardiac adaptations, collectively referred to as the athlete’s heart. In some cases, however, this may mimic the phenotypic expression of varying pathological conditions, often related to SCD/A. Clearly, this crossover complicates the differential diagnosis associated with cardiac screening. Ethnicity mediates cardiac adaptation within the adult athlete, yet little is known regarding the paediatric athlete, further complicating the distinction between physiological adaptation and cardiac pathology. The overarching aim of this thesis is to provide a comprehensive assessment of the competitive Arab and black paediatric athlete, using 12-lead-electrocardiogram (ECG) and transthoracic echocardiography. Study 1 (Chapter 4), employed a systematic review with meta-analysis to describe the ECG and echocardiographic manifestations of the paediatric athlete’s heart, and examine the impact of age, race, and sex on cardiac remodeling responses to competitive sport. Paediatric athletes demonstrated a greater prevalence of training-related and -unrelated ECG changes than non-athletes, with prevalence greater in black than white paediatric athletes. After accounting for chronological age, left ventricular (LV) structural parameters were larger among paediatric athletes than non-athletes, whilst posterior wall thickness during diastole was larger in black than white athletes. Paediatric athletes chronological age, and ethnicity are mediating factors on electrophysiological and LV structural remodelling. Study 2 (Chapter 5), new international recommendations, outperformed both the Seattle and 2010 ESC criteria, reducing false positive rates while yielding a ’fair’ (0.77, 95% CI 0.61 to 0.93) diagnostic accuracy for cardiac pathology that may predispose to SCD/A in a paediatric athlete. In clinical context, the ’chance’ of detecting cardiac pathology within a paediatric male athlete with a positive ECG (+ve Likelihood Ratio=9.0) was 8.3%, whereas a negative ECG (−ve Likelihood Ratio=0.4) was 0.4%. In extension to these investigations, Study 3 (Chapter 6), employed ‘biological’ age (by radiological X-ray) assessment to T-wave inversion (TWI) interpretation on the paediatric athletes ECG. TWI confined to V1–V3 was predicted by black ethnicity and biological age &lt;16 years, but not chronological age &lt;16 years. Secondly, biological age outperformed chronological age criterion in the categorisation of ‘physiological’ to ‘pathological’ TWI in V1-V4, offering potential refinement to new international recommendations for interpretation in the male paediatric athlete ECGs. Study 4 (Chapter 7), using allometric modelling we present measures of cardiac chamber and aortic root morphology independent of body surface area, ethnicity, chronological, and biological age. We also presented chronological age independent LV and RV measures of function in male Arab and black paediatric athletes. This data may prove useful to the differential diagnosis in the paediatric athlete, with upper limits of physiological remodelling and lower limits of function defined by Z-scores to ease clinical interpretation. Furthermore, these data will allow for serial assessment relative to allometric growth in the paediatric athlete necessitating annual follow-up. The empirical studies conducted within this thesis have furthered our understanding of the electrophysiological, structural and functional adaptations of the paediatric athlete’s heart. It is hoped these works will aid cardiac screening within the paediatric athlete.