Exercise testing in the evaluation of coronary artery disease

Exercise testing, after having established the indication (Tables 1 and 2) is not only an important method for detection of coronary artery disease, it also enables delineation of exercise capacity and permits assessment of medical and surgical treatment. A subnormal increase in heart rate or blood pressure, or even a decrease in blood pressure, during exercise may frequently be found in patients with known coronary artery disease or in those at high risk of developing subsequent coronary events. Downsloping ST segment depression is highly specific for the presence of coronary artery disease; the specificity of upsloping ST segment depression can be increased on requiring this pattern to consist of a 2 mm depression 0.08 s beyond the J point. Consideration of the QTc interval may also be useful in patients with upsloping ST segment depression. Marked ST segment depression and early onset of ST segment depression during exercise is related to increasing severity of the disease while the duration of ST segment depression bears no certain relevance. ST segment elevation may be associated with transmural myocardial ischemia, left ventricular aneurysm or variant angina. An increase in the R wave amplitude appears indicative of multiple vessel disease, while a reduction in septal Q wave amplitude is suggestive of left anterior descending coronary artery occlusion. The current concept of testing asymptomatic patients for coronary artery disease has low predictive value. Post-myocardial infarction exercise testing is an objective method for evaluation of prognosis and guiding management. In the assessment of the results of aorto-coronary bypass surgery, the finding of persistent angina and/or ST segment depression during exercise is indicative of residual ischemia; normalization of the exercise ECG in the presence of a high-level exercise capacity is usually associated with good coronary perfusion. In order to provide maximum diagnostic utility, exercise testing must take into consideration other clinical findings as well as the prevalence of disease in the respective population. With respect to the coronary angiographic findings as well as the incidence of coronary events, the predictive value of exercise testing may be notably increased on consideration of multiple clinical and exercise variables. The exercise test has evolved into a clinically important noninvasive method for the evaluation of the functional aspects of the heart.