Table 2. Grading of angina pectoris by the Canadian Cardiovascular Society classification system

Class       Description of stage
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Class I     Ordinary physical activity does not
            cause angina, such as walking, climbing
            stairs.  Angina [occurs] with
            strenuous, rapid, or prolonged exertion at
            work or recreation.

Class II    Slight limitation of ordinary activity.
            Angina occurs on walking or climbing
            stairs rapidly, walking uphill,
            walking or stair climbing after meals,
            or in cold, or in wind, or under
            emotional stress, or only during the few
            hours after awakening.  Walking more than two
            blocks on the level and climbing more than
            one flight of ordinary stairs at a normal
            pace and in normal condition.

Class III   Marked limitations of ordinary physical
            activity. Angina occurs on walking one
            to two blocks on the level and climbing one
            flight of stairs in normal conditions and
            at a normal pace.

Class IV    Inability to carry on any physical activity
            without discomfort -- angina symptoms may be
            present at rest.

Source: Campeau L. Grading of angina pectoris [letter].
Circulation, 54:522-523, 1976.  Copyright 1976, American Heart
Association, Inc. Used with permission.