or aged 75 years or older. in patients with non-st elevation acute coronary syndrome current guidelines also recommend immediate administration of dual antiplatelet therapy upon diagnosis; clopidogrel and ticagrelor are indicated in this setting, with ticagrelor considered superior for patients undergoing early invasive strategy (see later). however, emerging evidence questions this strategy. as with aspirin, it is necessary to administer a loading dose. glycoprotein iib/iiia inhibitors glycoprotein iib/iiia inhibitors are a class of intravenous antiplatelet agents used in patients undergoing percutaneous coronary intervention, consisting of abciximab, eptifibatide and tirofiban. patients presenting with st elevation that will be reperfused with percutaneous coronary intervention may receive one of the above agents at the time of catheterization, or perhaps before. administering eptifibatide or tirofiban may also be reasonable in patients presenting with nst-acs who are considered of intermediate or high risk and are treated with early invasive strategy. anticoagulants anticoagulants in acute coronary syndrome are targeted against the coronary blood clot, as well as towards prevention of thrombotic complications, like formation of blood clots in the ventricles, stroke, pulmonary embolism or deep vein thrombosis. patients undergoing pci also need an anticoagulant to prevent catheter thrombosis. options include unfractionated heparin, enoxaparin (a low molecular weight heparin), fondaparinux (a pentasaccharide antagonist of factor xa) and bivalirudin (a direct thrombin inhibitor); all the above agents are given parenterally (subcutaneously or intravenously). unfractionated heparin has the disadvantage of requiring dose adjustment based on a laboratory exam, activated partial thromboplastin time (aptt). in stemi patients choice depends on the reperfusion strategy used (see below); bivalirudin is used when pci is employed only, while in the same case fondaparinux is not preferred. similarly, in non-ste acs bivalirudin too is only used when an early invasive strategy is chosen. reperfusion main article: reperfusion therapy coronary angiography of a patient with acute myocardial infarction presenting with st elevation and undergoing primary percutaneous coronary intervention; arrow points at partial occlusion of left circumflex coronary artery; star indicates tip of the guide wire that has been inserted in the artery through the occlusion.coronary angiography of the same patient, after dilation of the artery with balloon and placement of stent. the occlusion has been successfully treated.the concept of reperfusion has become so central to the modern treatment of acute myocardial infarction, that we are said to be in the reperfusion era. patients who present with suspected acute myocardial infarction and st segment elevation (stemi) or new bundle branch block on the 12 lead ecg are presumed to have an occlusive thrombosis in an epicardial coronary artery. they are therefore candidates for immediate reperfusion, either with thrombolytic therapy, percutaneous coronary intervention (pci) or when these therapies are unsuccessful, bypass surgery. individuals without st segment elevation are presumed to be experiencing either unstable angina (ua) or non-st segment elevation myocardial infarction (nstemi). they receive many of the same initial therapies and are often stabilized with antiplatelet drugs and anticoagulated. if their condition remains (hemodynamically) stable, they can be offered either late coronary angiography with subsequent restoration of blood flow (revascularization), or non-invasive stress testing to determine if there is significant ischemia that would benefit from revascularization. if hemodynamic instability develops in individuals with nstemis, they may undergo urgent coronary angiography and subsequent revascularization. the use of thrombolytic agents is contraindicated in this patient subset, however. the basis for this distinction in treatment regimens is that st segment elevations on an ecg are typically due to complete occlusion of a coronary artery. on the other hand, in nstemis there is typically a sudden narrowing of a coronary artery with preserved (but diminished) flow to the distal myocardium. anticoagulation and antiplatelet agents are given to prevent the narrowed artery from occluding. at least 10% of patients with stemi do not develop myocardial necrosis (as evidenced by a rise in cardiac markers) and subsequent q waves on ekg after reperfusion therapy. such a successful restoration of flow to the infarct-related artery during an acute myocardial infarction is known as "aborting" the myocardial infarction. if treated within the hour, about 25% of stemis can be aborted. rehabilitation additional objectives are to prevent life-threatening arrhythmias or conduction disturbances. this requires monitoring in a coronary care unit and protocolized administration of antiarrhythmic agents. antiarrhythmic agents are typically only given to individuals with life-threatening arrhythmias after a myocardial infarction and not to suppress the ventricular ectopy that is often seen after a myocardial infarction. cardiac rehabilitation aims to optimize function and quality of life in those affected by a heart disease. this can be with the help of a physician, or in the form of a cardiac rehabilitation program. physical exercise is an important part of rehabilitation after a myocardial infarction, with beneficial effects on cholesterol levels, blood pressure, weight, stress and mood. some patients become afraid of exercising because it might trigger another infarct. patients are encouraged to exercise, and should only avoid certain exerting activities. local authorities may place limitations on driving motor vehicles. in most cases, the advice is a gradual increase in physical exercise during about 6–8 weeks following an mi. if it doesn't feel too hard for the patient, the advice about exercise is then the same as applies to anyone else to gain health benefits, that is, at least 20–30 minutes of moderate exercise on most days (at least five days per week) to the extent of getting slightly short of breath. some people are afraid to have sex after a heart attack. most people can resume sexual activities after 3 to 4 weeks. the amount of activity needs to be dosed to the patient's possibilities. special cases cocaine cocaine associated myocardial infarction should be managed in a manner similar to other patients with acute coronary syndrome, except that beta blockers should not be used and benzodiazepines should be administered early. the treatment itself may have complications. if attempts to restore the blood flow are initiated after a critical period of only a few hours, the result may be a reperfusion injury instead of amelioration. wilderness setting in wilderness first aid, a possible heart attack justifies evacuation by the fastest available means, often meaning the initiation of a medevac. the suspicion or provisional diagnosis of an mi means that it is inappropriate for the patient to walk out of the wilderness setting and will require them to be carried or conveyed in a vehicle. aspirin, nitroglycerin, and oxygen can all be given with relative ease in a wilderness setting and should be administered as soon as possible in suspected cases of mi. wilderness management of cardiac arrest differs slightly from that carried out in an urban setting in that it is generally considered acceptable to terminate a resuscitation attempt after 30 minutes if there has been no change in the patient's condition. air travel certified personnel traveling by commercial aircraft may be able to assist an mi patient by using the on-board first aid kit, which may contain some cardiac drugs (such as glyceryl trinitrate spray, aspirin, or opioid painkillers), an aed, and oxygen. pilots may divert the flight to land at a nearby airport. cardiac monitors are being introduced by some airlines, and they can be used by both on-board and ground-based physicians.