ABSTRACT
For convenience, angina can be graded from I to IV according to the New York Heart Association classification. Class I and II are mild to moderate and classes III and IV are moderate to severe and unstable angina respectively. Class I and II angina rarely increase the risk of an operation, but from moderately severe angina to unstable angina the increased risk will range from 3-20%. Patients should therefore be carefully examined pre-operatively and beta-blockers added, where appropriate, to cope with the stress of the operation.
