Abstract
Objective : Although athlete's heart is usually considered a reversible physiologic adaptation to hemodynamic overload, some may progress to a pathological state such as cardiomyopathy. The transition process should be clarified.
Materials and methods : Endomyocardial biopsy specimens taken from 18 athletes, were microscopically examined and findings compared to those in control group of 12 hypertrophic cardiomyopathy (HCM), 12 hypertensive heart disease (HHD), and 8 normotensive hearts (NT).
Results : The athlete's hearts showed ECG changes in T wave change in 18/18 (giant negative T wave in 8/18), ventricular premature beat in 2/18, high voltage QRS in 13/18, and abnormal Q in 4/18 cases. Their ventriculogram revealed apical hypertrophy in 8/18 (cycle racer4, runner 1, boxer 1), diffuse hypertrophy in 5/18 and LV midportion hypertrophy in 1/18, and mild hypofunction with less than 60% ejection fraction in 6/18 cases. Results of the histological examination were as follows : mean diameter of the myocytes was 18μ in the right ventricle and 22μ in the left ventricle and the myocyte-disorientation area comprised 45%. The disorientation grade was less than that in HCM, but more than that in either HHD or NT, and the area became wider with aging and prolonged athletic career. The small fibrotic area was similar to that in NT, and less than that in HCM or HHD.
Conclusion : Disorientation of myocyte lines in athlete's heart indicates the initial stage of remodeling in the myocardium to adapt to hemodynamic stress. When the overload is excessive and persistent, the disorientation mimics the disarray in HCM of the apical hypertrophy type and the process may become irreversible resulting in an undesirable prognosis.
