Abstract 20002: Transient Myocardial Injury, Microvascular Dysfunction and Decreased Segmental Function in Less Fit Recreational Marathon Runners
Objective: Although exercise improves health, strenuous activity may alter myocardial function and raise biomarkers. We evaluated exercise-induced myocardial anomalies in recreational athletes.
Methods and Results: 20 healthy amateur runners were prospectively evaluated 6-8 weeks before and <48h after a marathon. Exercise tests, body anthropometrics, blood analysis, and magnetic resonance imaging (MRI) were performed. Runners with segmental function decrease were re-evaluated at 3 months. VO2 max was 53.2 ml/kg/min (95%CI 49.4-57.1) and all stress tests were negative for ischemia. All runners completed the marathon (232±40min), losing 3.2±1kg hydrous mass. Nt-ProBNP increased in all (37±21 vs. 128±74pg/ml, p<0.01) while troponin increased in 50% (clinically significant in 3). No changes in global left (LV)/right ventricular volumes/functions were observed. However, 53% of LV segments decreased function in patchy distribution. Compared to baseline, global myocardial perfusion decreased (time to 50% max. upslope on contrast kinetics 19.2±4 vs. 21.4±4msec, p<0.01) and edema/injury increased (relative T2 STIR 177±20 vs. 196±20%, p<0.01). On per-segment analysis, change in LV segmental function correlated with change in microvascular perfusion (rho=-0.23, p<0.001) and edema (rho=-0.13, p=0.001). On multivariable regression, decrease in LV segmental function was associated with fitness level, loss of hydrous mass, decrease in microvascular perfusion, and increase in myocardial edema (R2=0.49; all p<0.05). Myocardial changes were fully reversible by 3 months.
Conclusion: Completing a marathon incurs a patchy decrease in segmental wall function associated with increased myocardial edema and decreased microvascular perfusion. These fully reversible alterations are more widespread in runners with lower fitness levels and greater dehydration.
- © 2010 by American Heart Association, Inc.