Data_Sheet_1.docx

Abstract

Background: Cardiac magnetic resonance (CMR) combined with late gadolinium enhancement (LGE) has revealed an increased incidence of myocardial fibrosis (MF) in athletes compared to healthy controls. Objective: The aim of this systematic research and meta-analysis is to investigate CMR indices in athletes compared to sedentary controls, including T1 values, myocardial extracellular volume (ECV) and positive LGE indicative of non-specific fibrosis, also to discuss the differences between young and veteran athletes. Methods: The protocol included searching, up to October 2021, of MEDLINE, Web of Science and Cochrane databases for original studies assessing fibrosis via CMR in athletes. Results: The research yielded 14 studies including in total 1312 individuals. There was a statistically significant difference in LGE fibrosis between the 118/759 athletes and 16/553 controls (Z=5.2, P<0.001, I2=0%, PI=0.45). Notably, LGE fibrosis differed significantly between 546 (14.6%) veteran and 140 (25.7%) young athletes (P=0.002). At 1.5T, T1 values differed between 117 athletes and 48 controls (P<0.0001). A statistically significant difference was also shown at 3T (110 athletes vs. 41 controls, P=0.0004), as well as when pooling both 1.5T and 3T populations (P<0.00001). Mean ECV showed no statistically significant difference between these groups. Conclusions: Based on currently available data, we reported that overall LGE based non-specific fibrosis and T1 values differ between athletes and sedentary controls, in contrast to ECV values. Age of athletes seems to have impact on the incidence of MF. Future prospective studies should focus on the investigation of the underlying pathophysiological mechanisms.