Troponin positive acute coronary syndrome versus myocardial infarction

The World Health Organization's classic definition of acute myocardial infarction requires that at least two of the following three criteria are met: a history of typical symptoms of ischaemic chest discomfort; evolutionary electrocardiographic tracings involving the development of Q waves; and an increase in the creatinine kinase level greater than twice the upper reference limit.1 While this definition is clear cut, many patients who have had myocardial infarction will be excluded. Recent developments in the detection of small quantities of myocardial necrosis using serum cardiac troponin levels have prompted a new definition of myocardial infarction. This may well lead to an increase in the number of patients diagnosed and improved patient outcomes, but it may also confuse clinicians, epidemiologists, and most importantly patients themselves.