P649Harmonic cardiac adaptation of myocardial structure and mass in the course of a multistage marathon over 4.486 km. (28th August 2018) - Klenk, C; Brunner, H; Nickel, T; Sagmeister, F; Infanger, D; Billich, C; Beer, M; Schuetz, U; Schmidt-Trucksaess, A