• There are 3 principal presentations of UA:
▶▶ Rest angina (angina occurring at rest and prolonged, usually
>20 min)
▶▶ New-onset (<2 months) severe angina
▶▶ Increasing angina (increasing in intensity, duration, and/or
frequency).
Grading of angina pectoris is made according to the Canadian
Cardiovascular Society (CCS) classification (Table 1). NSTEMI
generally presents as prolonged, more intense rest angina or angina
equivalent.
• Because symptoms are similar and the differentiation of
UA/NSTEMI and STEMI requires medical evaluation, these
guidelines will refer to prediagnostic clinical presentation as ACS,
defined as UA or MI (NSTEMI or STEMI) (Fig. 1).
Table 1. Grading of Angina Pectoris
According to CCS Classification
Class
Description of Stage
I
"Ordinary physical activity does not cause … angina," such as walking or
climbing stairs. Angina occurs with strenuous, rapid, or prolonged exertion
at work or recreation.
II
"Slight limitation of ordinary activity." Angina occurs on walking or climbing
stairs rapidly; walking uphill; walking or stair climbing after meals; in cold, in
wind, or under emotional stress; or only during the few hours after awakening.
Angina occurs on walking more than 2 blocks on the level and climbing more
than 1 flight of ordinary stairs at a normal pace and under normal conditions.
III
"Marked limitations of ordinary physical activity." Angina occurs on walking
1-2 blocks on the level and climbing 1 flight of stairs under normal conditions
and at a normal pace.
IV
"Inability to carry on any physical activity without discomfort—anginal
symptoms may be present at rest."
Adapted with permission from Campeau L. Circulation. 1976;54:522-523.
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