Cardiac Remodeling Versus Cardiomyopathies in Athletes

Prolonged and intensive training results in morphological and functional remodeling of cardiac chambers. Several determinants affect the remodeling including sport disciplines and the volume and intensity of the training. Harmonic dilatation of all chambers, mild hypertrophy, and low-normal ejection fraction can be observed as part of the spectrum of the morpho-functional changes. For these reasons, the traditional cardiac magnetic resonance (CMR) normal reference values for ventricles and atria should not be used, particularly in those athletes involved in endurance disciplines, where the cardiac adaptation can be particularly pronounced. In some cases, the remodeling can overlap with early stage of cardiomyopathies generating clinical concern for differential diagnosis. CMR is the gold standard for the assessment of biventricular volume, mass, and global and regional systolic function. In addition, tissue characterization sequences including mapping techniques can reveal tissue abnormalities that are not part of physiological adaptation to exercise. These features make CMR a valuable tool to better distinguish the normal remodeling of athlete’s heart from cardiomyopathies in daily clinical practice. CMR is particularly important in case of non-diagnostic or inconclusive echocardiogram, in the presence of abnormal electrocardiogram, symptoms, or arrhythmias. In such cases, the detection of structural heart abnormalities should possibly be obtained in earlier stage and is crucial due to the potential related risk of sudden cardiac death. After a section elucidating the determinants of cardiac remodeling and the common features of athlete’s heart in term of imaging findings, ten clinical cases are shown to highlight the practical role of CMR in this setting of patients.