Current management of acute myocardial infarction

Abstract

Acute myocardial infarction is a devastating cardiac clinical event, which is the result of progressive coronary arteriosclerosis. Coronary heart disease is a major health concern that accounts for a significant number of hospitalizations, health care expenditures, and deaths. Recent advancements in the nature and pathophysiology of progressive coronary disease and infarction have allowed us to curb the natural course of the disease, shorten hospital stays, and improve patient outcomes. Focused history taking and physical examination, with the assistance of the appropriate laboratory studies and an electrocardiogram, facilitate the rapid identification of a patient with myocardial infarction. Overall clinical results will be improved by minimizing the time from diagnosis to therapy. Several initial measures are readily available to the physician at the time of the patient's arrival in the hospital emergency room. Consideration regarding relief of pain, anticoagulation, and contraindications for thrombolytic therapy should accompany the initial evaluation. For patients in whom the diagnosis is in doubt, adjunctive confirmatory testing and imaging studies should be urgently sought. Elderly patients have a higher mortality rate from infarction, so an aggressive approach in this group of patients is warranted. Administration of thrombolytic therapy or primary angioplasty will be most efficacious in a majority of patients. The evolution of adjunctive medications will further improve efficacy and avoid reinfarction. Proper dosage and timing of adjunctive medications, along with dosage titration based on hemodynamic response, will facilitate the best possible results. Rapid restoration of flow down a suddenly occluded epicardial coronary vessel is the primary end point in therapy. With this in mind, there has been an increasing trend toward mechanical restoration of flow by means of primary angioplasty in centers where this technologic capability is available. Close attention to the patient's hemodynamic status along with rapid identification and therapy of periinfarction arrhythmias will help to avoid clinical complications. When peripheral perfusion is compromised, hemodynamic monitoring, inotropic medications, and mechanical assistance may become necessary. Subsequent severe pump failure is usually the result of a devastating mechanical complication. Patients with mechanical complications have a high associated event-related mortality rate. Urgent identification of the nature of the complication with the use of invasive and noninvasive imaging studies, mechanical and inotropic assistance, and emergency surgical correction may be lifesaving. Careful patient follow-up and medical therapy aimed at maintaining left ventricular geometry, reducing ischemia and related events, and attempting to retard the progression of arteriosclerosis with anti-ischemic agents and lipid-lowering therapy, as well as estrogen replacement in female patients, can reduce the incidence of subsequent events and prolong life. New insights into the interactions of macromolecules, medications, and hormones with the coronary endothelium and atherosclerotic plaque are helping to shape the evolution of appropriate therapy for myocardial infarction and coronary heart disease in general.