Ref: KV Krishna Das - Clinical Medicine 4th Edition pg no:212 Exercise Electrocardiography (Syn: Stress Tests, Treadmill Test) This refers to the recording of the electrical activity of the hea while the individual is subjected to the stress of graded exercises. The bicycle ergometer or the treadmill is currently used for most exercise testing programs. There are various exercise protocols such as the Bruce protocol or the Naughton protocol to assess effo tolerance. In all these protocols the subject is made to exercise in stages of increasing workloads until the end points are achieved. During exercise, various parameters like occurrence of symptoms, fluctuations in blood pressure changes in the ST segment, and changes in cardiac rate and rhythm are closely monitored. Although the stress test is fairly safe, it has to be done only under close medical supervision. Currently the main indications for stress testing are: 1. As a diagnostic tool in the evaluation of symptoms like effo induced chest pain, or palpitation. 2. To assess the prognosis and in the risk stratification of patients with coronary aery disease, either after acute events like myocardial infarction or angina, or after therapeutic interventions like coronary angioplasty or by pass surgery. 3. To assess the functional capacity in patients with ischemic hea disease, valvular hea disease, cardiomyopathy and patients undergoing cardiac surgery. 4. As a screening test for ischemic hea disease in subjects with an intermediate or high probability for the disease. The test is considered positive if there is flat or down sloping ST segment depression of 1 mm or more, ST segment elevation, inversion of U waves, fall in blood pressure and ischemic symptoms associated with ECG changes. Standard contraindications to exercise testing include acute myocardial infarction, high risk unstable angina pectoris, severe aoic stenosis, congestive cardiac failure, acute pulmonary embolism or infarction, acute myocarditis or pericarditis, aoic dissection, uncontrolled severe systemic hypeension > 200/100 mm Hg, high grade hea blocks, uncontrolled symptomatic cardiac arrhythmias, any acute systemic illness or an unwilling patient. The indications to terminate exercise testing includes inappropriate drop in blood pressure or deceleration of the hea rate with increasing workload and exercise, moderate to severe angina, sustained VT, ST depression more than 3 mm or ST elevation in non Q leads, hypeensive response > 250/115 mm Hg, patient exhaustion, fatigue, leg cramps or claudication pain and subject's desire to stop the test. Exercise stress testing has a sensitivity of about 80 to 85% and a specificity of 85 to 90% for the diagnosis of coronary aery disease. In patients with ischemic hea disease, positive stress test is an indication for fuher tests such as coronary angiography.