T wave abnormalities in top-ranking athletes: effects of isoproterenol, atropine, and physical exercise.

Eight cases of top-ranking athletes with "repolarization disorders" are reported. All subjects were asymptomatic and were otherwise suited for excellent cardiovascular performances. Seven athletes did not show any evidence of heart disease. Seven had MVP (mitral valve prolapse). Umprompted variability of ECG tracings was observed in three cases. Both isoproterenol infusions (IS) and maximal physical effort (EX) normalized T wave (abnormalities in 100% of cases, while atropine (AT) was ineffective despite an increase in heart rate greater than that caused by IS. The authors emphasize the usefulness of combined use of the EX and IS tests in ascertaining the clinical significance of T wave changes in healthy athletes. A "neurogenic" mechanism is proposed by the authors for the pathogenesis of these T wave abnormalities. This hypothesis may explain the umprompted variability of ECG tracings and T wave normalization after maximal physical effort and isoproterenol infusion.