What is the role of troponin cardiac markers in the diagnosis of myocardial infarction (MI)?

Updated: Jul 30, 2021
  • Author: Kamal (Komo) Gursahani, MD, MBA; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

Recognizing that cardiac troponin measurements may be elevated in disease states not primarily related to myocardial ischemia, a fourth universal definition of acute MI was developed by the American College of Cardiology (ACC), European Society of Cardiology (ESC), American Hospital Association (AHA), and World Health Federation (WHF) in 2018.

First, myocardial injury is defined as elevated cardiac troponin values with at least one value above the 99th percentile upper reference limit. Myocardial injury is considered acute if there is a rise and/or fall of cardiac troponin values. The term "myocardial infarction" is to be used when there is acute myocardial injury with clinical evidence of acute myocardial ischemia and with detection of a rise and/or fall of cardiac troponin values within at least one value above the 99th percentile upper reference limit and at least one of the following features [16] :

  • Symptoms of myocardial ischemia
  • New ischemic electrocardiographic (ECG) changes
  • Development of pathological Q waves, imaging evidence of new loss of viable myocardium, or new regional wall motion abnormality in a pattern consistent with ischemia
  • Identification of a coronary thrombus by angiography or autopsy

The definition was updated to manage the fact that nonischemic myocardial injury, as occurs in association with heart failure, arrhythmia, myocarditis, renal failure, pulmonary embolism, and percutaneous or surgical coronary procedures, also result in elevated cardiac markers as cardiac troponins become the standard. [17]


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