Decisions about early management of acute myocardial infarction require great care and astuteness, since the threat of sudden death is the greatest during the first few hours after onset of infarction. General measures of acute care include relief of pain and management of arrhythmia. Drug therapy with beta-adrenergic blocking agents or vasodilators may also be indicated. Other measures that may be considered (some of which are controversial) include hemodynamic monitoring, mechanical circulatory assistance, ambulatory electrocardiographic monitoring, exercise testing, modification of risk factors, and coronary angiography. Intracoronary administration of streptokinase, which is still investigational, has shown marked preservation of myocardial tissue in some cases.