Comprehensive CMR to differentiate between fitness levels amongst veteran endurance athletes

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): British Heart Foundation. Background Myocardial fibrosis has been demonstrated to be highly prevalent amongst endurance athletes. However, it is unknown whether endurance athletes with a greater exercise capacity have an increased prevalence of fibrosis. Purpose To determine whether greater maximal exercise threshold is associated with increased myocardial fibrosis on cardiac magnetic resonance (CMR) in veteran endurance athletes. Methods 50 healthy veteran (aged > 50 years old) endurance athletes (cyclists/triathletes) who train >10 hours/week for >15 years underwent comprehensive CMR assessment and functional threshold power (FTP) cycling testing. Focal myocardial fibrosis was measured quantitively from late gadolinium enhancement (LGE) imaging. Diffuse myocardial fibrosis was identified using global native T1 mapping of mid-left ventricular (LV) slices whilst extracellular volume (ECV) was calculated using haematocrit on the same day as CMR. Statistical analysis between groups was performed using independent t-test for nominal values and chi-squared for ordinal values. Results Athletes were divided into high and low performance groups based on FTP assessment (median 240.8 Watts). High performance athletes were significantly younger with increased bi-ventricular size and reduced right ventricular ejection fraction (RVEF) at rest (Table 1). However, there was no statistical difference in focal fibrosis, ECV or native T1 between the groups. Conclusion Maximal effort capacity did not appear to influence the prevalence of cardiac fibrosis which may be related to alternative factors such as cumulative exercise exposure. However, higher performing athletes had increased bi-ventricular size, particularly affecting the more compliant right ventricle (RV). Further larger studies are needed to confirm these findings.