A treadmill stress test has various contraindications such as acute aortic dissection, symptomatic severe aortic stenosis and acute myocardial infarction, according to the American Heart Association. Absolute contraindications to the stress test include unstable angina not previously stabilized by medical therapy and uncontrolled symptomatic heart failure. Exercise testing may supersede relative contraindications such as electrolyte abnormalities, high-degree atrioventricular block and severe arterial hypertension if the benefits outweigh the underlying risks.
A patient with aortic stenosis should only undergo treadmill stress testing under the supervision of a physician who understands the patient’s condition, the American Heart Association warns. The physician should terminate the test if the patient experiences premature beats, increased exercise slows the heart rate, or there is inappropriate blood pressure augmentation. Myocardial infarction and death may occur during the exercise, so physicians should use good judgment on which patients should undergo the test. Interventions for patients with myocardial infarction include medical therapy, coronary revascularization or use of thrombolytic agents.
It is essential to assess the risk of treadmill stress testing on patients with unstable angina, the American Heart Association advises. Physicians should only carry out the test if the patient is free of heart failure symptoms or active ischemic symptoms for a minimum of 48 hours. Physicians may use exercise testing to evaluate patients who have exercise-induced arrhythmias such as atrioventricular block and supraventricular arrhythmias, although the test may not be useful in some patients.