Critical Illness - Heart Attack

This is defined as the death of heart muscle, due to inadequate blood supply as evidenced by all of the following three criteria:

• Compatible clinical symptoms, such as crushing central chest pain.
• Characteristic ECG changes, which can be either of the following:
1. New pathological Q-waves as defined below, or
2. ST-segment and T-wave changes indicative of myocardial ischaemia that may progress to myocarcial infaction (heart attack), but only when accompanied by raised cardiac markers as described in 3.
• Pre-intervention raised cardiac markers:
1. Trop T greater than 1,0 ng/ml, or
2. Trop I greater than 0,5 ng/ml, or
3. CK-MB mass greater than two times the upper normal values in acute presentation phase, or
4. Total CPK elevation of greater than two times the normal values, with at least 6% being CK-MB.

The evidence must show a definite acute myocardial infarction. Other acute coronary syndromes, including but not limited to angina, are not covered by this definition. For the purpose of this definition, new pathological Q-waves mean the following:

• Any Q-wave in leads V1 through V3, Q-waves greater than or equal to 30 ms (0.03s) in leads I, II, AVL, AVF, V4, V5 or V6.
• The Q-wave changes must be present in any two contiguous leads, and be greater than of equal to 1 mm in depth.

The evidence must show a definite acute myocardial infarction. Other acute coronary syndromes, including but not limited to angina, are not covered by this definition. ECG changes indicative of myocardial ischaemia that may progress to myocardical infarction (heart attack) mean the following:

• Patients with ST-segment elevation:
  New or presumed new ST segment elevation at the J point in two or more contiguous leads with the cut-off points greater than or equal to 01.mV in other leads. Contiguity in the frontal plane is defined by the lead sequence AVL, I, inverted AVR, II, AVF, III.
• Patients without ST-segment elevation:
  a. ST-segment depression.
  b. T-wave abnormalities only.