Table Canadian Cardiovascular Society Classification System for Angina Pectoris Class Activities Triggering Chest Pain 1 Strenuous, rapid, or prolonged exertion Not usual physical activities (eg, walking, climbing stairs) 2 Walking rapidly Walking uphill Climbing stairs rapidly Walking or climbing stairs after meals Cold Wind Emotional stress 3 Walking, even 1 or 2 blocks at usual pace and on level ground Climbing stairs, even 1 flight 4 Any physical activity Sometimes occurring at rest Adapted from Braunwald E, Antman EM, Beasley JW, et al: ACC / AHA Guidelines for the management of patients with unstable angina and non-ST segment elevation myocardial infarction: A report of the American College of Cardiology / American Heart Association Task Force on Practice Guidelines (Committee on the management of patients with unstable angina).