Monday, October 22, 2007

Universal Definition of Myocardial Infarction

Title: Universal Definition of Myocardial Infarction

Author(s): Thygesen K, Alpert JS, White HD, et al., on behalf of the Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction.Citation: Eur Heart J. 2007;28:2525-2538.

Date Posted: 10/22/2007

Perspective: The following are 12 points to remember about this expert consensus document:

1. Clinically, one can classify myocardial infarction (MI) into different types.

2. Type 1 is spontaneous MI related to ischemia due to a primary coronary event such as plaque erosion and/or rupture, fissuring, or dissection.

3. Type 2 is MI secondary to ischemia due to either increased oxygen demand or decreased supply (e.g., coronary artery spasm, coronary embolism, anemia, arrhythmias, hypertension, or hypotension).

4. Type 3 is sudden unexpected cardiac death, including cardiac arrest, often with symptoms suggestive of myocardial ischemia, accompanied by presumably new ST elevation, or new left bundle branch block, or evidence of fresh thrombus in a coronary artery by angiography and/or at autopsy, but death occurring before blood samples could be obtained, or at a time before the appearance of cardiac biomarkers in the blood.

5. Type 4a is MI associated with percutaneous coronary intervention.

6. Type 4b is MI associated with stent thrombosis, as documented by angiography or at autopsy.

7. Type 5 is MI associated with coronary artery bypass grafting.
8. Myocardial cell death can be recognized by the appearance in the blood of different proteins released into the circulation from the damaged myocytes: myoglobin, cardiac troponin T and I, creatine kinase, lactate dehydrogenase, as well as many others.

9. The preferred biomarker for myocardial necrosis is cardiac troponin (I or T), which has nearly absolute myocardial tissue specificity as well as high clinical sensitivity, thereby reflecting even microscopic zones of myocardial necrosis.

10. An increased value for cardiac troponin is defined as a measurement exceeding the 99th percentile of a normal reference population (one-quarter upper reference limit). Detection of a rise and/or fall of the measurements is essential to the diagnosis of acute MI.

11. New ST elevation at the J-point in two contiguous leads with the cut-off points: ≥0.2 mV in men or ≥0.15 mV in women in leads V2–V3 and/or ≥0.1 mV in other leads suggests acute myocardial ischemia.

12. The change in the definition of MI based on elevated biomarker measurement exceeding the 99th percentile of a normal reference population will have a substantial impact on the identification, prevention, and treatment of cardiovascular disease throughout the world.

Debabrata Mukherjee, M.D., F.A.C.C.

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