Abstract

Coronary disease CLINICAL IMPLICATIONS OF THE NEW DEFINITION OF MYOCARDIAL INFARCTION John K French, Harvey D White Heart 2004; 90:99–106 yocardial infarction (MI) can be considered from several perspectives: clinical, electrocardiographic, biochemical, pathological, epidemiological, and imaging. The M diagnosis of MI has psychological, social, and legal implications. MI is often used as a major end point in clinical trials. WORLD HEALTH ORGANIZATION (WHO) DEFINITION Historically, there has been tacit agreement as to the meaning of the term ‘‘myocardial infarction’’. The World Health Organization definition, which has been widely used, requires the presence of two of the following three features: symptoms of myocardial ischaemia, elevation of cardiac marker (enzyme) concentrations in the blood, and a typical electrocardiographic pattern w1 involving the development of Q waves or persistent T wave changes. Using specific and highly sensitive immunoassays for myocardial proteins, such as cardiac troponins T and/or I, it is now possible to identify patients with small areas of myocardial necrosis. The emphasis on cardiac protein markers in the new American College of Cardiology/ European Society of Cardiology (ACC/ESC) definition of MI, published in September 2000, has simplified the classification of MI. The new diagnostic criteria include a characteristic rise and fall