A 27-year-old female athlete (running) with ECG-Holter evidence of >15,000 premature ventricular contractions per day. Cine images show a mild enlargement of LV (A,E) with normal wall thickness and mildly reduced ejection fraction (EF: 52%). Short-tau inversion recovery (B) and LGE (F) sequences show unremarkable findings. T1 mapping (T1 map in (C), bullseye plot in (D)) shows slightly increased T1 values, with average septal native-T1 of 1076 ms (site specific normal values < 1045 ms). Pre- and post-contrast T1 mapping were as analyzed to generate the ECV map (G), which demonstrated mild increase of ECV values (bullseye plot in (H); average septal ECV 30.6%; normal values < 27%), suggestive of slight expansion of the myocardial interstitium. The finding of increased native-T1 and ECV values should suggest an early non-ischemic dilated cardiomyopathy or maladaptive remodeling to exercise training, rather than a physiological adaptation to training.