WHO criteria for the diagnosis of acute myocardial infarction

The WHO criteria for the diagnosis of acute myocardial infarction (MI) requires the presence of at least two of three elements:

• History of ischaemic-type chest discomfort
• Evolutionary ECG changes
• Rise and fall in serum cardiac markers.

No further time should be wasted before reperfusing an ST elevation MI (STEMI), generally by thrombolysis. In the case of non-ST elevation MI (NSTEMI), the serum cardiac markers become elevated.

The commonly used cardiac markers are creatinine kinase (CK), creatinine kinase-myocardial type (CK-MB) and troponin (Trop)-I/Trop-T. The earliest time at which the various cardiac markers rise are shown in the table.

Marker	Initial rise	Peak levels	Back to normal
Myoglobin	1 – 4 h	6 – 7 h	24 h
Troponin I	3 – 12 h	24 h	5 – 10 days
Troponin T	3 – 12 h	12 h – 2 days	5 – 14 days
CK-MB	3 – 12 h	24 h	48 – 72 h
LDH	10 h	24 – 48 h	10 – 14 days

Further reading

1. Criteria for the diagnosis of acute myocardial infarction (UpToDate)