ACUTE MYOCARDIAL INFARCTION: DEFINITION, DIAGNOSIS, AND THE EVOLUTION OF CARDIAC MARKERS

In the United States, heart disease is the leading cause of death and accounts for 1 in every 4 deaths each year. Coronary artery disease (CAD) is the most common type of heart disease and is the principle source for deaths due to heart disease. CAD refers to a group of diseases including stable angina, unstable angina, myocardial infarction (MI), and sudden cardiac death. An estimated 735,000 individuals suffer an MI annually, with the majority (roughly 525,000) being first time heart attacks. The current diagnosis of MI is based on the rise and fall of cardiac markers, preferably troponin, with at least one measurement being above the 99th percentile Upper Reference Limit (URL), with strong clinical evidence. The advancement in cardiac troponin assays has provided an opportunity for clinicians to more quickly identify acute coronary disorders and to determine the best treatment protocol for patients. The fifth generation assays, known as high sensitivity troponin (hs-Tn) assays, were FDA approved in the US only in 2017. As we take a closer look at the high sensitivity troponin assay, we need to take into consideration issues related to this assay in all steps of the testing process (pre-analytical, analytical, and post-analytical). In this article, we define MI and the challenges that come with diagnosing MI, and the history and evolution of cardiac markers over the years is summarized. The future of MI and cardiac disease identification is described by identifying the advantages and disadvantages of high sensitivity troponin assays.