HOW THE EXERCISE ELECTROCARDIOGRAM IS USED IN CLINICAL-PRACTICE IN PATIENTS WITH SUSPECTED CORONARY-ARTERY DISEASE

Clinical use of a test should be evaluated not only on the change of p retest probability but also on the increased confidence in the judged probability, and on the decision of recommending additional tests or t herapy after test results. Before and after the test, cardiologists re ferring a patient for exercise electrocardiogram for suspected coronar y artery disease were asked to estimate the probability of coronary ar tery disease and the minimal and maximal value of their estimate (plau sible range), to judge whether to refer the patient for coronary angio graphy, and to specify patient's treatment. After the test, the percen tage of patients with estimated probability less-than-or-equal-to 20% increased (from 53 to 69%; p = 0.005) and the percentage of patients w ith intermediate probability (between 21 and 80%) decreased (from 37 t o 16%; p = 0.0001). The mean plausible range decreased from pre- to po st-test assessment (31 +/- 23 to 15 +/- 16%; p = 0.0001), indicating a n increase in cardiologists' confidence in their estimates. After the test, the percentage of cardiologists who wished to either refer or no t refer patients for coronary angiography increased (from 4 to 13%, p < 0.005; and from 37 to 65%, p < 0.0001, respectively). Test results e nable cardiologists to change the assessment of disease probability, t he confidence in their own estimates, and their judgment of whether to refer patients for coronary angiography.