[Does syndrome X exist?].

The syndrome X is an entity characterised by the association of chest pain on exercise and a positive exercise stress test in patients with normal coronary angiography. However, this diagnosis can only be admitted when all other causes of angina with normal coronary arteries have been excluded. They include angina secondary to coronary artery spasm and myocardial hypertrophy. A review of the literature based on 26 publications recensing 822 patients shows that these criteria are not always respected: a really positive exercise stress test is an inclusion criterion in only 13 studies and concerns only 313 patients (38.1%); myocardial hypertrophy and coronary spasm were formally excluded in only 278 (33.3%) and 228 patients (27.7%) respectively. Taking into consideration only the patients of these 26 series with a positive exercise stress test after exclusion of coronary spasm and myocardial hypertrophy, 143 (17.4%) may be considered to be due to syndrome X. Syndrome X is a real entity but its incidence is usually overestimated. It is appropriate to distinguish it from other conditions associating, though the exercise stress test is negative, chest pain on effort and the positivity of a test considered to be indicative of myocardial ischaemia.