PROGNOSTIC VALUE OF EXERCISE TESTING FOR ISCHAEMIC HEART DISEASE*

"The augmented two-step test, when negative, completely excludes the presence of coronary artery disease " (Master, 1972). In some millenial age, clinical scientists may devise a true prognostic test, or battery of tests. At the conclu-sion of our investigations, we may be able to advise a patient with a reasonable degree of confidence that he or she will live in good health for a specified period such as 13 % years. But at present, we are still struggling to make a simple biomodal decision. Is a patient who shows no clinical manifestations of disease healthy, or (in the context of our conference) is there an increased risk of myocardial infarction and sudden death? Will the patient who has already sustained a non-fatal infarc-tion follow a normal clinical course, or is there an increased risk of reinfarction and death? The process can be illustrated with respect to one of the most commonly employed prognostic tests of the cardiologist- the appearance of a deep horizontal or downward sloping depression of the ST segment of the electrocardiogram during exercise. The prognostic ideal is illustrated in the upper panel of Fig. 1. Even during maximum effort, normal individuals would develop a depression averaging only 0.5 mm, and the scatter in this response would be sufficiently small to avoid any overlap with that group of patients where the prognosis is poor. Unfortunately, the actual situation is all too commonly as represented in the lower panel. A propor-tion of subjects with a normal prognosis show substantial ST segmental depression, and a proportion of patients Correspondence to