The contemporary management of acute myocardial infarction

The acute coronary syndromes cover disease entities ranging from unstable angina and non-Q wave myocardial infarction (MI) to Q wave myocardial infarction. These syndromes share a common pathogenesis and represent various stages of plaque rupture and thrombosis with varying degrees of vessel occlusion and subsequent myocardial necrosis The pathogenesis of acute coronary syndromes involves a vulnerable plaque that ruptures or fissures, initiating a cascade of inflammatory and thrombotic mediators in and around the coronary artery wall that results in varying degrees of arterial occlusion and distal microembolization.(23) Significant 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 specific patient characteristics, and about half die before reaching the hospital, usually because of ventricular arrhythmias. The in-hospital mortality is around 10% and most commonly is caused by cardiogenic shock.(36).