[The exercise test in congenital aortic stenosis].

Exercise tests can be carried out without risk in a child or young adult with asymptomatic congenital aortic stenosis. In such a case, the ECG at rest gives only a very poor indication of the severity of the stenosis, which often becomes worse with age. The only sinister findings is that of repolarisation defects, which are almost always absent at rest. Exercise, by causing an imbalance between myocardial oxygen consumption and oxygen transport, will cause "ischaemic" signs to appear on the ECG. At the same time, the absence of compensation of pressure is a very important sign of poor tolerance; the test can usefully be concluded by using a floating catheter to measure the pulmonary capillary pressure. The correlation between a positive test and the stenotic pressure gradient, measured on catheterisation at rest, is good; but "negative" tests may be found in certain cases with a tight stenosis, especially if maximal rate could not be reached. In cases of stenoses which were initially mild or moderate, this test is very useful as a follow-up procedure, as such stenoses may become worse with age and require surgical correction. It is also useful for assessing the results of surgery, and of rehabilitation.