The contemporary management of acute myocardial infarction

The acute coronary syndromes cover disease entities ranging from unstable a ngina and non-Q wave myocardial infarction (MI) to Q wave myocardial infarc tion. These syndromes share a common pathogenesis and represent various sta ges of plaque rupture and thrombosis with varying degrees of vessel occlusi on and subsequent myocardial necrosis The pathogenesis of acute coronary syndromes involves a vulnerable plaque t hat ruptures or fissures, initiating a cascade of inflammatory and thrombot ic mediators in and around the coronary artery wall that results in varying degrees of arterial occlusion and distal microembolization.(23) Significan t thrombotic coronary occlusion often develops in arteries that have only a minimal (10% to 40%) degree of stenosis at baseline.(21) The unstable and "vulnerable" plaque, not necessarily one that is severely stenotic, is most prone to rupture (Fig. 2). About 1.5 million cases of acute myocardial infarction occur every year in the United States resulting in approximately 400,000 to 500,000 deaths per year. The overall mortality rate ranges from 5% to 30% depending on specifi c patient characteristics, and about half die before reaching the hospital, usually because of ventricular arrhythmias. The in-hospital mortality is a round 10% and most commonly is caused by cardiogenic shock.(36).