[The diagnostic value of bloodless methods and follow-up in young asymptomatic subjects with positive exercise test (author's transl)].

Fifty asymptomatic subjects, aged 22 to 40, with normal resting ECG and "ischemic" ST depressions during exercise were followed for 44 +/- 18 months. Coronary events occurred only in two cases. Unexpectedly in 12 subjects the response to maximal exercise became normal. In 25 subjects forced hyperventilation, exercise test after nitroglycerin (TNG), and after propranolol (P) were performed. Hyperventilation determined abnormalities of ventricular recovery in all cases. TNG did not improve the response to exercise, as it does in coronary patients, and even significantly decreased the "ischemic threshold"; after P the exercise test became normal in 20 subjects, while in 5 the electrocardiographic ST depressions were markedly reduced. The responses to pharmacological tests after the follow-up period were similar to the first observation. In 8 subjects, in which exercise ST depressions were particularly impressive, Tallium 201 myocardial scanning at rest and during exercise was performed. Myocardial perfusion imaging did not reveal any defect, thus confirming the non-ischemic nature of the ECG abnormalities. Our results confirm the low predictive accuracy (4%) of a positive stress test in a young asymptomatic population and suggest that, among non-invasive methods, exercise response after TNG is usefull in recognizing the "false positive" tests.