PROBABILISTIC JUDGMENT AND CLINICAL DECISION IN THE USE OF EXERCISE ELECTROCARDIOGRAM

The aim of this study was to verify, in a clinical setting whether dec isions to perform coronary angiography and to modify drug treatment ar e influenced by cardiologists' perception of coronary artery disease p robability. Cardiologists referring patients for exercise electrocardi ograms, because of suspected coronary artery disease, were asked to es timate the probability of coronary artery disease before and after the test. After the test they had to judge whether to refer patients for coronary angiography or to change the current therapy. Cardiologists a ssigned a higher coronary artery disease probability to patients they would refer for coronary angiography (87.5%; 95% confidence interval 8 1.8-93.2%) than to those they would not refer (6.1%; 95% confidence in terval 5.0-7.2; p < 0.0001). They also assigned a higher probability o f coronary artery disease when they decided to increase drug treatment (44.8%; 95% confidence interval 33.3-56.3%) than when it was decided to reduce treatment (17.4%; 95% confidence interval 3.5-31.3%; p < 0.0 001). In conclusion, there is a close relationship between cardiologis ts' assessment of coronary artery disease probability and their diagno stic and therapeutic decisions when interpreting the exercise electroc ardiogram.