Universal Definition of Myocardial Infarction

Abstract

The word “ Universal ” has many applications most notably as an adjective to describe the entire physical universe. One cannot help wondering, therefore, whether the current redefinition1 will be robust enough to be applied to other humanoid life forms in this or other galaxies.2 If it were only robust enough to be applied on planet earth then that in itself would be “a small step for a man but a giant leap for mankind”. Taking the first word from the title of the recent editorial of one the new guideline’s lead authors, the past history, and likely future of this important topic has been/will remain more “evolution” than “big-bang”.3 Harvey White ably sets the scene for the “universal definition” of myocardial infarction (UD-MI) by reviewing the process of change and evolution that led up to the last “consensus definition” for myocardial infarction (CD-MI), first published in 2000.4 While an important step in the right direction, that redefinition was flawed at inception owing to a fundamental problem with the troponin assays available at that time.5 Despite the recommendation that the key biomarker evidence for CD-MI should be a “Maximal concentration of troponin T or I exceeding the decision limit (99th percentile of the values for a reference control group) on at least one occasion during the first 24 h after the index clinical event”, the technology to deliver this requirement did not exist at that time. This is because the CD-MI guidance appropriately stipulated that “Acceptable imprecision (coefficient of variation (CV)) at the 99th percentile for each assay should be defined as ⩽10%.” The 99th centile refers to the top of the “normal range” while the 10% CV is a measure of the assay imprecision (at a defined concentration of troponin). For most of the …