Abstract 4194: Increased Incidence of Myocardial Fibrosis with Reduced Cardiac Function in Elite High-Endurance Athletes: A Cardiovascular Magnetic Resonance (CMR) Study
Background: Athletes possess greater relative risk of sudden death due to cardiovascular causes, where autopsies reveal diffuse myocardial fibrosis. Indirect biochemical evidence suggests that athletes have increased collagen degradation and fibrosis. Utilizing CMR based late enhancement (LE) imaging to assess myocardial fibrosis, we hypothesized that fibrosis is a feature of the athlete’s heart and is associated with reduced cardiac function.
Methods: 48 elite athletes (25 male, age 32±13 years) were prospectively recruited, and a control group of 6 healthy individuals (4 male, 29±9 years). After assessment of LV function, T1-weighted LE was performed on a 1.5T MRI system. Experienced observers assessed LE images visually for the presence of fibrosis. Extent of fibrosis was assessed quantitatively, using semi-automated detection where regions that had signal enhancement above a threshold of 5 standard deviations from the mean signal of healthy myocardium, were considered to be fibrosis.
Results: 77.1% of athletes had non-ischemic diffuse LE, compared with 16.7% of controls (figure 1⇓). Extent of myocardial fibrosis in athletes who had visual evidence for LE was 10.7±3.3%. Athletes with fibrosis also had increased LVEDVI (117±19 vs. 98±15 ml/m, p<0.05), LVESVI (44±11 vs. 34±10 ml/m, p<0.05), and LVSVI (73±11 vs. 64±7 ml/m, p<0.05), compared to those without fibrosis.
Conclusion: This is the first investigation to provide evidence for the increased incidence of myocardial fibrosis in elite high-endurance athletes, which is associated with depressed cardiac function. These findings may have implications for the safety of sport and prescreening athletes.