An important expert consensus document on the third universal definition of myocardial infarction (MI) was released today as part of the ESC Congress 2012, and simultaneously released online in JACC. Developed jointly by the ACC, the European Society of Cardiology, the American Heart Association and the World Heart Federation, the updated definition has important and immediate implications for physicians and our patients.

The task force had previously defined MI in a consensus document in 2000 and again in 2007. This new 2012 definition includes new insights and data over the past few years, and will be universally used to diagnose patients and to define endpoints in clinical trials.
 
At the center of the third definition of myocardial infarction, is the detection of a rise and/or fall of cardiac biomarker values, with at least one of the values being elevated (i.e., > 99th percentile upper reference limit). The preferred cardiac biomarker of necrosis is cTn. In addition, at least one of the five following supportive criteria should be met:

1. Symptoms of ischemia
2. New (or presumably new) significant ST/T wave changes or left bundle-branch block (LBBB)
3. Development of pathological Q waves on ECG
4. Imaging evidence of new loss of viable myocardium or regional wall motion abnormality
5. Identification of intracoronary thrombus by angiography or autopsy

The new document notably adds to the previous definition the identification of intracoronary thrombus as one of the supportive criteria for the diagnosis of acute myocardial infarction and sets out the levels of troponin required for the diagnosis of procedural related MI after PCI, CABG and other cardiac and non-cardiac procedures.

Here in the US, the authors of the document communicated with the US Food and Drug Administration (FDA) during the development of the definition, and we anticipate the definition to be used in future clinical trials to ensure consistency moving forward.

Each year, about 1.2 million people in the U.S. alone have heart attacks, often resulting in death. With such drastic statistics, awareness and education of preventative steps for our patients are crucial. On the physician side, in order to analyze trends over time, as the authors note, “it is important to have consistent definitions to quantify adjustments when biomarkers or other diagnostic criteria change.”

There is still a lot of work to be done on a global scale, and as the document notes, for countries with limited economic resources where advancements in technology may be lacking, in addition to cultural, financial, structural and organizational problems, further analysis will be needed to determine their ability to adhere to the new definition. The College is committed to working with other organizations globally towards this effort.