ACUTE CORONARY SYNDROMES

Unstable Angina ▪ Clinical syndrome resulting from rupture of an unstable plaque or from a critically stenotic stable plaque ▪ It is defined by any of the following: ▴ Rest angina-angina occurring at rest and usually lasting >20 minutes within a week before presentation ▴ New-onset angina-angina of at least Canadian Cardiovascular Society class III severity within 2 months before initial presentation ▴ Worsening angina-previously diagnosed angina that is more frequent, longer in duration or lower in threshold, and has worsened by at least one class within 2 months after initial presentation to at least Canadian Cardiovascular Society class III severity Myocardial Infarction ▪ Diagnosed by the presence of at least two of the following three criteria: ▴ Prolonged chest pain (>30 minutes) or anginal equivalent ▪ Subdivisions ▴ NSTEMI-characterized by an increase in troponin I or T in the clinical setting of acute coronary syndrome and/or STsegment depression >1 mm in two or more contiguous leads ▴ STEMI-characterized by ST-segment elevation >1 mm in two or more contiguous leads or left bundle branch block (LBBB) not known to be old ▪ Unstable angina cannot be distinguished from NSTEMI at presentation.