Pre-participation cardiac screening (PCS) of the athlete has recently become mandatory by many national and international sporting governing bodies and aims to identify those at risk of sudden cardiac death (SCD) from an undiagnosed cardiac condition. The term athletes’ heart (AH) describes the physiological adaptation that occurs from chronic exposure to exercise training however, this process can mimic cardiac remodelling caused by pathological conditions such as cardiomyopathy. Transthoracic echocardiography (TTE) plays an integral role during PCS however, differentiation from inherited conditions is often based on a ‘one size fits all’ interpretation of echocardiographic derived measures. To improve the sensitivity and specificity of echocardiography in PCS it is pertinent to understand normal physiological cardiac adaptation in specific sporting disciplines. This thesis focuses on cardiac structure and function of the elite, male, rugby football league (RFL) athlete with the application of TTE including novel speckle tracking echocardiography (STE). The aims of this thesis were 1) to establish left ventricular (LV) structural and functional indices of the senior RFL athlete using TTE and STE and a mathematical model of the structural-functional relationship; 2) to determine structural and functional indices of the right heart of the senior RFL athlete using TTE and STE; 3) to provide a comparative and holistic, structural and functional assessment of the junior and senior RFL athletic heart using TTE and STE and 4) To assess variation in cardiac parameters across the competitive season in the senior RFL athlete using TTE and STE. A comprehensive cardiac assessment of the elite RFL athlete was established throughout this thesis. The LV has a predominance for normal LV geometry irrespective of age or seasonal time point. Mathematical modelling highlights the interaction of divergent effects of left ventricular cavity size (LVIDd) and mean wall thickness (MWT) on LV function to maintain a normal ejection fraction (EF). Significant regional variation in LV STE parameters was apparent including lower apical rotation and twist parameters in senior athletes compared to controls (8.2 ± 3.9 ̊ vs. 11.2 ± 4.6 ̊ and 14 ± 4.7 vs 16.1 ± 4.6 ̊ respectively) suggesting potential adaptive mechanisms to training. The right ventricle (RV) and right atrium (RA) are larger in athletes compared to controls even after scaling (proximal right ventricular outflow dimension in parasternal long axis (RVOTplax) (23 ± 3 vs. 20 ± 2 mm/(m2)0.5), proximal right ventricular outflow dimension in parasternal short axis (RVOT1) (24 ± 3 vs. 21 ± 3 mm/(m2)0.5) and RA volume (RAvol) (22 ± 5 vs. 16 ± 4 ml/(m2)1.5)). The RVOT and RA are also larger in senior compared to junior athletes (RVOTplax (23 ± 3 vs. 22 ± 3 mm/(m2)0.5, RVOT1 (24 ± 3 vs. 23 ± 3 mm/(m2)0.5 and RAvol (22 ± 5 vs. 21 ± 5 ml/(m2)1.5) suggesting that the right heart is more sensitive to chronic training. Despite significant structural remodelling, RV function in the RFL athlete is normal as assessed by TTE (right ventricular fractional area change (RVFAC) > 33% and STE RV strain (ɛ) < -21%), irrespective of age and time of season. Significant seasonal functional changes were observed with STE as apical rotation (pre-season, 9.8 ± 4 ̊; mid-season, 6.1 ± 2.8 ̊; end-season, 5.8 ± 3.2 ̊ and post-season break, 6.6 ± 3.1 ̊) and twist (pre-season, 16.6 ± 4.7o; mid-season, 12.6 ± 4o; end-season 12.1 ± 4.5o and post-season break, 12.4 ± 3.5 ̊) are higher at pre-season than at any other time-point, highlighting physiological variation during the RFL season. The use of standard and novel echocardiographic techniques have provided further understanding of the normal physiological adaptation of the AH in RFL athletes which may lead to improvements in PCS of this athlete group.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:755788 |
| Date | January 2018 |
| Creators | Forsythe, L. C. |
| Contributors | Oxborough, D. ; George, K. ; Papadakis, M. |
| Publisher | Liverpool John Moores University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://researchonline.ljmu.ac.uk/9398/ |
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