Significance of a positive exercise ECG in middle-aged and old athletes as judged by echocardiographic, radionuclide and follow-up findings

To study the pathologic and prognostic significance of--and possible underlying mechanisms for--a pathological exercise ECG in athletes, two age-matched groups were selected from a total population of 117 middle-aged and old endurance athletes: Group A: 21 with a pathological exercise-ECG, and group B: 21 with normal exercise-ECGs. Data from 201-thallium perfusion scintigraphy, 99 m-technetium multiple gated acquisition ventriculography (MUGA), resting echocardiography and 3 years follow-up are as follows: None had thallium findings indicating reversible myocardial ischaemia, but one from group A had a probable old myocardial infarction. All had normal resting MUGA, but group A men slightly more often presented a subnormal increase in ejection fraction according to exercise MUGA than group B men (9/20 vs 4/21). The former also more often had ventricular hypertrophy (LVH) (19/21 vs 14/21). However, apart from slightly longer ventricular filling time among group A men the echocardiograms revealed no group differences e.g. in cardiac dimensions or in indices of systolic or diastolic function. Regardless of exercise-ECG response, 18/42 athletes had one or more value of left ventricular dimensions or diameter exceeding the 95th percentile of the normal range. Since one patient from group A had asymmetric septal hypertrophy, one developed cardiomyopathy during the 3 years follow-up and one had a previous myocardial infarction, only 3/21 had cardiac disease which might explain the pathological exercise-ECG. Thus, pathological exercise-ECG rarely signifies heart disease in athletes, and very rarely coronary heart disease. Rather, the pathological exercise-ECG may be related to LVH and various subtle alterations in cardiac physiology following long-term endurance training.