Clinical Calculators

Killip Classification (severity of heart failure in acute myocardial infarction)

In acute myocardial infarction (acute coronary syndrome), classifies the severity of heart failure into 4 classes from lung rales, a third heart sound and shock

1 item left

Class (choose the one that fits the findings, such as on auscultation)

Class I (no pump failure)

Class II (mild to moderate heart failure)

Class III (severe heart failure, pulmonary edema)

Class IV (cardiogenic shock)

Cautions

  • A classification of the severity of heart failure from physical findings in acute myocardial infarction (acute coronary syndrome), in 4 classes. The Japanese Circulation Society guideline says severity can be assessed mainly from auscultation findings, and that it is also useful for predicting prognosis.
  • Classes II and III are separated by the extent of the rales (50% of the lung fields is the guide). Class II is rales over less than 50%, or a third heart sound. The guideline table only lists the findings of each class and does not say how to decide when findings of more than one class overlap.
  • Choose Class IV when the findings of cardiogenic shock are present together. The guideline defines cardiogenic shock as hypotension below 90 mmHg lasting 30 minutes or more, with signs of poor peripheral circulation. It also says that even with a blood pressure of 90 mmHg or more, signs of tissue hypoperfusion mean pre-shock, which is handled like shock. Do not decide Class IV from the blood pressure number alone.
  • A third heart sound reflects severe left ventricular dysfunction with raised left ventricular filling pressure, and is used in this classification.
  • Advances in treatment centered on reperfusion therapy have been shown to raise survival even in patients with shock (guideline).

References

  1. Killip T 3rd, Kimball JT. Treatment of myocardial infarction in a coronary care unit. A two year experience with 250 patients. Am J Cardiol. 1967;20(4):457-464. (Full text) (original not seen) PMID: 6059183[Original article]
  2. Joint Working Group of the Japanese Circulation Society and 8 other societies (Japanese Coronary Association, Japanese Association for Thoracic Surgery, Japanese Society of Intensive Care Medicine, Japanese Association of Cardiovascular Intervention and Therapeutics, Japanese Society for Cardiovascular Surgery, Japanese College of Cardiology, Japanese Association of Cardiac Rehabilitation, Japanese Heart Rhythm Society). JCS 2018 Guideline on Diagnosis and Treatment of Acute Coronary Syndrome (in Japanese). Chair: Kimura K. Published 2019-03-29 (updated 2022-12-09). (Table 3 (p. 19), 1.3.2 Auscultation findings (pp. 19-20), 1.8.1 Factors affecting the prognosis of STEMI (p. 27)) https://www.j-circ.or.jp/cms/wp-content/uploads/2018/11/JCS2018_kimura.pdf[Guideline]

Checked on: 2026-10-15

Disclaimer

This calculation is intended to support the judgment of healthcare professionals. Results are for reference only; decisions about diagnosis and treatment must be made by the responsible healthcare professional. The values you enter never leave your device.