BACKGROUND: There are no published data on the safety of cardiopulmonary exercise testing in patients with aortic stenosis. METHODS: In this retrospective descriptive study, we examined 347 consecutive patients with aortic stenosis who underwent cardiopulmonary exercise testing at a tertiary referral center. We recorded major events including death, nonfatal major events (cardiac arrest, symptomatic or sustained ventricular or supraventricular tachycardia, myocardial infarction, and syncope), and minor events such as hypotension, nonsustained supraventricular and ventricular arrhythmias, positive electrocardiographic changes, and angina. RESULTS: Of 347 patients, 65 (19%) had mild, 145 (42%) had moderate, and 137 (40%) had severe aortic stenosis by echocardiographic criteria. No major events occurred during the tests. Minor events occurred in a total of 97 patients (28%), including 10 patients who developed supraventricular arrhythmias without hypotension; and one who had asymptomatic nonsustained ventricular tachycardia. CONCLUSION: Symptom-limited cardiopulmonary exercise testing in cardiology-referred patients with aortic stenosis with preserved systolic function appears to be associated with very low risk of major adverse cardiovascular events during testing. (C) 2012 Elsevier Inc. All rights reserved. . The American Journal of Medicine (2012) 125, 704-708