The Killip Classification is frequently used during acute myocardial infarction. First published in 1967, this system focuses on physical examination and the development of heart failure to predict risk as described below:

Class I: No evidence of heart failure (mortality 6%)
Class II: Findings of mild to moderate heart failure (S3 gallop, rales < halfway up lung fields or elevated jugular venous pressure; mortality 17%)
Class III: Pulmonary edema (mortality 38%)
Class IV: Cardiogenic shock defined as systolic blood pressure < 90 mm Hg and signs of hypoperfusion such as oliguria, cyanosis, and sweating (mortality 67%)

The original data from 1967 showed the above mortality rate in each class. This was before reperfusion therapy (thrombolytics and/or PCI). With advances in therapy, the mortality rates have declined about 30-50% in each class.