ACUTE CORONARY SYNDROMES. FIRST PART: CLASSIFICATION, PATHOPHISIOLOGY AND DIAGNOSIS

Acute coronary syndromes represent a continuum of acute myocardial ischemia, which includes acute transmural myocardial infarction with ST segment elevation, myocardial infarction without ST segment elevation, and unstable angina pectoris. The acute coronary syndromes are a common cause for an urgent hospital admission and also a major burden on health care resources in industrialized countries today.In practice, two categories of patients may be encountered. Patients with chest pain and persistent ST segment elevation (or LBBB) and patients with chest discomfort with ECG abnormalities without ST segment elevation, but ST segment depression, or T wave inversion, flat or pseudo-normalization, or nonspecific ECG changes or normal ECG.Acute coronary syndromes are the consequence of an acute or sub-acute primary reduction of myocardial oxygen supply provoked by disruption of an atherosclerotic plaque associated with inflammation, thrombosis, vasoconstriction and microembolization. The traditional approach to the assessment of patients with suspected acute coronary syndrome is based on three criteria: assessment of clinical symptoms, electrocariographic findings on admission electrocardiogram and measurements of biochemical markers.