Table 1.

Three main presentations of unstable angina

• Angina at rest—Also prolonged, usually > 20 minutes

• Angina of new onset—At least CCS class III in severity

• Angina increasing—Previously diagnosed angina that has become more frequent, longer in duration, or lower in threshold (change in severity by ≥ 1 CCS class to at least CCS class III)

CCS=Canadian Cardiovascular Society