1999 Update: ACC/AHA Guidelines for the Management of Patients With Acute Myocardial Infarction: Executive Summary and Recommendations

Class IIa

1. Availability of a first-responder defibrillation program in a tiered response system. 2. Healthcare providers educate patients/families about signs and symptoms of AMI, accessing EMS, and medications.

Class IIb

1. Twelve-lead telemetry. 2. Prehospital thrombolysis in special circumstances (eg, transport time greater than 90 minutes).

Class I

1. Emergency department (ED) AMI protocol that yields a targeted clinical examination and a 12-lead electrocardiogram (ECG) within 10 minutes and a door-to-needle time that is less than 30 minutes.

Routine Measures

1. Supplemental oxygen, intravenous access, and continuous electrocardiographic monitoring should be established in all patients with acute ischemic-type chest discomfort. 2. An ECG should be obtained and interpreted within 10 minutes of arrival in the ED in all patients with suspected acute ischemic-type chest discomfort.

Class I

1. Overt pulmonary congestion. 2. Arterial oxygen desaturation (SaO₂ less than 90%).

Class IIa

1. Routine administration to all patients with uncomplicated myocardial infarction (MI) during the first 2 to 3 hours.

Class IIb

1. Routine administration of supplemental oxygen to patients with uncomplicated MI beyond 3 to 6 hours.

Class I

1. For the first 24 to 48 hours in patients with AMI and congestive heart failure (CHF), large anterior infarction, persistent ischemia, or hypertension. 2. Continued use (beyond 48 hours) in patients with recurrent angina or persistent pulmonary congestion.

Class IIa

None.

Class IIb

1. For the first 24 to 48 hours in all patients with AMI who do not have hypotension, bradycardia, or tachycardia. 2. Continued use (beyond 48 hours)*¹ in patients with a large or complicated infarction.

Class III

1. Patients with systolic blood pressure less than 90 mm Hg or severe bradycardia (less than 50 bpm).

Class I

1. A dose of 160 to 325 mg should be given on day 1 of AMI and continued indefinitely on a⇓ daily basis.

Class I

1. Sinus bradycardia with evidence of low cardiac output and peripheral hypoperfusion or frequent premature ventricular complexes at onset of symptoms of AMI. 2. Acute inferior infarction with type I second- or third-degree atrioventricular (AV) block associated with symptoms of hypotension, ischemic discomfort, or ventricular arrhythmias. 3. Sustained bradycardia and hypotension after administration of nitroglycerin. 4. For nausea and vomiting associated with administration of morphine. 5. Ventricular asystole.

Class IIa

1. Symptomatic patients with inferior infarction and type I second- or third-degree heart block at the level of the AV node (ie, with narrow QRS complex or with known existing bundle-branch block [BBB]).

Class IIb

1. Administration concomitant with (before or after) administration of morphine in the presence of sinus bradycardia. 2. Asymptomatic patients with inferior infarction and type I second-degree heart block or third-degree heart block at the level of the AV node. 3. Second- or third-degree AV block of uncertain mechanism when pacing is not available.

Class III

1. Sinus bradycardia greater than 40 bpm without signs or symptoms of hypoperfusion or frequent premature ventricular contractions. 2. Type II AV block and third-degree AV block and third-degree AV block with new wide QRS complex presumed due to AMI.

Class I

1. ST elevation (greater than 0.1 mV, two or more contiguous leads),†² time to therapy 12 hours or less,‡³ age less than 75 years. 2. BBB (obscuring ST-segment analysis) and history suggesting AMI.

Class IIa

1. ST elevation,*³ age 75 years or older.

Class IIb

1. ST elevation,†² time to therapy greater than 12 to 24 hours.*³ 2. Blood pressure on presentation greater than 180 mm Hg systolic and/or greater than 110 mm Hg diastolic associated with high-risk MI.

Class III

1. ST elevation,†² time to therapy greater than 24 hours,*³ ischemic pain resolved. 2. ST-segment⇓ depression only.

Primary Percutaneous Transluminal Coronary Angioplasty (PTCA)

Class I

None.

Class IIa

1. Patients with cardiogenic shock or persistent hemodynamic instability.

Class IIb

1. Patients with evolving large or anterior infarcts treated with thrombolytic agents in whom it is believed that the artery is not patent and adjuvant PTCA is planned.

Class III

1. Routine use of angiography and subsequent PTCA within 24 hours of administration of thrombolytic agents.

Class I

1. Failed angioplasty with persistent pain or hemodynamic instability in patients with coronary anatomy suitable for surgery. 2. AMI with persistent or recurrent ischemia refractory to medical therapy in patients with coronary anatomy suitable for surgery who are not candidates for catheter intervention. 3. At the time of surgical repair of postinfarction ventricular septal defect (VSD) or mitral valve insufficiency.

Class IIa

1. Cardiogenic shock with coronary anatomy suitable for surgery.

Class IIb

1. Failed PTCA and small area of myocardium at risk; hemodynamically stable.

Class III

1. When the expected surgical mortality rate equals or exceeds the mortality rate associated with appropriate medical therapy.⇓

Early Coronary Angiography and/or Interventional Therapy in Non–ST-Segment Elevation Cohort

Glycoprotein IIb/IIIa Inhibitors⇓

Early, General Measures

Class I

1. Selection of ECG monitoring based on infarct location and rhythm. 2. Bed rest with bedside commode privileges for initial 12 hours in hemodynamically stable patients free of ischemic-type chest discomfort. 3. Avoidance of Valsalva. 4. Careful attention to maximum pain relief.

Class IIb

1. Routine use of anxiolytics.

Class III

1. Prolonged bed rest (more than 12 to 24 hours) in stable patients without complications.

Management of Recurrent Chest Discomfort

Class I

1. Aspirin for pericarditis. 2. β-Adrenoceptor blockers intravenously, then orally for ischemic-type chest discomfort. 3. (Re)administration of thrombolytic therapy (alteplase) for patients with recurrent ST elevation. 4. Coronary arteriography for ischemic-type chest discomfort recurring after hours to days of initial therapy and associated with objective evidence of ischemia in patients who are candidates for revascularization.

Class IIa

1. Nitroglycerin intravenously for 24 hours, then topically or orally for ischemic-type chest discomfort.

Class IIb

1. Corticosteroids for pericarditis. 2. Indomethacin for pericarditis.

Balloon Flotation Right-Heart Catheter Monitoring

Class I

1. Severe or progressive CHF or pulmonary edema. 2. Cardiogenic shock or progressive hypotension. 3. Suspected mechanical complications of acute infarction, ie, VSD, papillary muscle rupture, or pericardial tamponade.

Class IIa

1. Hypotension that does not respond promptly to fluid administration in a patient without pulmonary congestion.

Class III

1. Patients with acute infarction without evidence of cardiac or pulmonary complications.

Class I

1. Patients with severe hypotension (systolic arterial pressure less than 80 mm Hg) and/or cardiogenic shock. 2. Patients receiving vasopressor agents.

Class IIa

1. Patients receiving intravenous sodium nitroprusside or other potent vasodilators.

Class IIb

1. Hemodynamically stable patients receiving intravenous nitroglycerin for myocardial ischemia. 2. Patients receiving intravenous inotropic agents.

Class III

1. Patients with acute infarction who are hemodynamically stable.

Class I

1. Cardiogenic shock not quickly reversed with pharmacological therapy as a stabilizing measure for angiography and prompt revascularization. 2. Acute mitral regurgitation or VSD complicating MI as a stabilizing therapy for angiography and repair/revascularization. 3. Recurrent intractable ventricular arrhythmias with hemodynamic instability. 4. Refractory post-MI angina as a bridge to angiography and revascularization.

Class IIa

1. Signs of hemodynamic instability, poor LV function, or persistent ischemia in patients with large areas of myocardium at risk.

Class IIb

1. In patients with successful PTCA after failed thrombolysis or those with three-vessel coronary disease to prevent reocclusion. 2. In patients known to have large areas of myocardium at risk with or without active ischemia.

Rhythm Disturbances

Class IIa

1. Either diltiazem or verapamil intravenously to slow a rapid ventricular response if β-adrenoceptor blocking agents are contraindicated or ineffective.

Class I

1. Ventricular fibrillation (VF) should be treated with an unsynchronized electric shock with an initial energy of 200 J; if unsuccessful, a second shock of 200 to 300 J should be given, and, if necessary, a third shock of 360 J. 2. Sustained (more than 30 seconds or causing hemodynamic collapse) polymorphic ventricular tachycardia (VT) should be treated with an unsynchronized electric shock using an initial energy of 200 J; if unsuccessful, a second shock of 200 to 300 J should be given, and, if necessary, a third shock of 360 J. 3. Episodes of sustained monomorphic VT associated with angina, pulmonary edema, or hypotension (blood pressure less than 90 mm Hg) should be treated with a synchronized electric shock of 100 J initial energy. Increasing energies may be used if not initially successful. 4. Sustained monomorphic VT not associated with angina, pulmonary edema, or hypotension (blood pressure less than 90 mm Hg) should be treated with one of the following regimens: a. Lidocaine: bolus 1.0 to 1.5 mg/kg. Supplemental boluses of 0.5 to 0.75 mg/kg every 5 to 10 minutes to a maximum of 3 mg/kg total loading dose may be given as needed. Loading is followed by infusion of 2 to 4 mg/min (30 to 50 μg/kg per minute). b. Procainamide: 20 to 30 mg/min loading infusion, up to 12 to 17 mg/kg. This may be followed by an infusion of 1 to 4 mg/min. c. Amiodarone: 150 mg infused over 10 minutes followed by a constant infusion of 1.0 mg/min for 6 hours and then a maintenance infusion of 0.5 mg/min. d. Synchronized electrical cardioversion starting at 50 J (brief anesthesia is necessary).

Class IIa

1. Infusions of antiarrhythmic drugs may be used after an episode of VT/VF but should be discontinued after 6 to 24 hours and the need for further arrhythmia management assessed. 2. Electrolyte and acid-base disturbances should be corrected to prevent recurrent episodes of VF when an initial episode of VF has been treated.

Class IIb

1. Drug-refractory polymorphic VT should be managed by aggressive attempts to reduce myocardial ischemia, including therapies such as β-adrenoceptor blockade, intra-aortic balloon pumping, and emergency PTCA/CABG surgery. Amiodarone, 150 mg infused over 10 minutes followed by a constant infusion of 1.0 mg/min for up to 6 hours and then a maintenance infusion of 0.5 mg/min may also be helpful.

Class III

1. Treatment of isolated ventricular premature beats, couplets, runs of accelerated idioventricular rhythm, and nonsustained VT. 2. Prophylactic administration of antiarrhythmic therapy when using thrombolytic agents.

Atropine

Class I

1. Symptomatic sinus bradycardia (generally, heart rate less than 50 bpm associated with hypotension, ischemia, or escape ventricular arrhythmia). 2. Ventricular asystole. 3. Symptomatic AV block occurring at the AV nodal level (second-degree type I or third-degree with a narrow-complex escape rhythm).

Class IIa

None.

Class III

1. AV block occurring at an infranodal level (usually associated with anterior MI with a wide-complex escape rhythm). 2. Asymptomatic sinus bradycardia.

Temporary Pacing

Class IIa

1. Stable bradycardia (systolic blood pressure greater than 90 mm Hg, no hemodynamic compromise, or compromise responsive to initial drug therapy).*⁶ 2. Newly acquired or age-indeterminate RBBB.*⁶

Class IIb

1. Newly acquired or age-indeterminate first-degree AV block.*⁶

Class III

1. Uncomplicated AMI without evidence of conduction system disease.

Temporary Transvenous Pacing†⁷

Class IIa

1. RBBB and LAFB or LPFB (new or indeterminate). 2. RBBB with first-degree AV block. 3. LBBB, new or indeterminate. 4. Incessant VT, for atrial or ventricular overdrive pacing. 5. Recurrent sinus pauses (greater than 3 seconds) not responsive to atropine.

Class IIb

1. Bifascicular block of indeterminate age. 2. New or age-indeterminate isolated RBBB.

Class III

1. First-degree heart block. 2. Type I second-degree AV block with normal hemodynamics. 3. Accelerated idioventricular rhythm. 4. BBB or fascicular block known to exist before AMI.

Permanent Pacing After AMI

Class IIb

1. Persistent advanced (second- or third-degree) block at the AV node level.

Class III

1. Transient AV conduction disturbances in the absence of intraventricular conduction defects. 2. Transient AV block in the presence of isolated LAFB. 3. Acquired LAFB in the absence of AV block. 4. Persistent first-degree AV block in the presence of BBB that is old or age indeterminate.

Emergency or Urgent Cardiac Repair of Mechanical Defects

Class I

1. Papillary muscle rupture with severe acute mitral insufficiency.⇓

Class III

1. Acute infarctectomy in hemodynamically stable patients.

Antithrombotics/Anticoagulants

Heparin

Class I

1. Patients undergoing percutaneous or surgical revascularization.⇓

Class IIb

1. Patients treated with nonselective thrombolytic agents, not at high risk, subcutaneous heparin, 7500 U to 12 500 U twice a day until completely ambulatory.

Class III

1. Routine intravenous heparin within 6 hours to patients receiving a nonselective fibrinolytic agent (streptokinase, anistreplase, urokinase) who are not at high risk for systemic embolism.⇓

β-Adrenoceptor Blocking Agents

Angiotensin-Converting Enzyme Inhibitors

⇓

Class IIa

1. All other patients within the first 24 hours of a suspected or established AMI, provided significant hypotension or other clear-cut contraindications are absent. 2. Asymptomatic patients with mildly impaired LV function (ejection fraction 40% to 50%) and a history of old MI.

Class IIb

1. Patients who have recently recovered from MI but have normal or mildly abnormal global LV function.

Class I

None.

Class IIa

1. Verapamil or diltiazem may be given to patients in whom β-adrenoceptor blockers are ineffective or contraindicated (ie, bronchospastic disease) for relief of ongoing ischemia or control of a rapid ventricular response with AF after AMI in the absence of CHF, LV dysfunction, or AV block.

Class IIb

1. In non–ST-elevation infarction, diltiazem may be given to patients without LV dysfunction, pulmonary congestion, or CHF. It may be added to standard therapy after the first 24 hours and continued for 1 year.

Class III

1. Nifedipine (short acting) is generally contraindicated in routine treatment of AMI because of its negative inotropic effects and the reflex sympathetic activation, tachycardia, and hypotension associated with its use. 2. Diltiazem and verapamil are contraindicated in patients with AMI and associated LV dysfunction or CHF.

Class I

None.

Class IIa

1. Correction of documented magnesium (and/or potassium) deficits, especially in patients receiving diuretics before onset of infarction. 2. Episodes of torsade de pointes–type VT associated with a prolonged QT interval should be treated with 1 to 2 g of magnesium administered as a bolus over 5 minutes.

Class IIb

1. Magnesium bolus and infusion in high-risk patients such as the elderly and/or those for whom reperfusion therapy is not suitable.

Noninvasive Evaluation of Low-Risk Patients

Class I

Class IIa

1. Dipyridamole or adenosine stress perfusion nuclear scintigraphy or dobutamine echocardiography before discharge for prognostic assessment in patients judged to be unable to exercise. 2. Exercise two-dimensional echocardiography or nuclear scintigraphy (before or early after discharge for prognostic assessment).

Class III

1. Stress testing within 2 to 3 days of AMI. 2. Either exercise or pharmacological stress testing at any time to evaluate patients with unstable postinfarction angina pectoris. 3. At any time to evaluate patients with AMI who have uncompensated CHF, cardiac arrhythmia, or noncardiac conditions that severely limit their ability to exercise. 4. Before discharge to evaluate patients who have already been selected for cardiac catheterization. In this situation, an exercise test may be useful after catheterization to evaluate function or identify ischemia in distribution of a coronary lesion of borderline severity.

Class I

None.

Class IIa

None.

Class IIb

1. Ambulatory (Holter) monitoring, signal-averaged ECG, heart rate variability, baroreflex sensitivity monitoring, alone or in combination with these or other tests, including functional tests (ejection fraction, treadmill testing) for risk assessment after MI, especially in patients at higher perceived risk, when findings might influence management issues, or for clinical research purposes.

Invasive Evaluation

Coronary Angiography and Possible PTCA

Class I

1. Patients with spontaneous episodes of myocardial ischemia or episodes of myocardial ischemia provoked by minimal exertion during recovery from infarction. 2. Before definitive therapy of a mechanical complication of infarction such as acute mitral regurgitation, VSD, pseudoaneurysm, or LV aneurysm. 3. Patients with persistent hemodynamic instability.

Class IIa

1. When MI is suspected to have occurred by a mechanism other than thrombotic occlusion at an atherosclerotic plaque. This would include coronary embolism, certain metabolic or hematological diseases, or coronary artery spasm. 2. Survivors of AMI with depressed LV systolic function (LV ejection fraction less than or equal to 40%), CHF, prior revascularization, or malignant ventricular arrhythmias. 3. Survivors of AMI who had clinical heart failure during the acute episode but subsequently demonstrated well-preserved LV function.

Class IIb

1. Coronary angiography performed in all patients after infarction to find persistently occluded infarct-related arteries in an attempt to revascularize the artery or to identify patients with three-vessel disease. 2. All patients after a non–Q-wave MI. 3. Recurrent VT or VF or both, despite antiarrhythmic therapy in patients without evidence of ongoing myocardial ischemia.

Class III

1. Routine use of coronary angiography and subsequent PTCA of the infarct-related artery within days after receiving thrombolytic therapy. 2. Survivors of MI who are thought not to be candidates for coronary revascularization.

Routine Coronary Angiography and PTCA After Successful Thrombolytic Therapy

Class IIa

None.

Class III

1. Routine PTCA of the stenotic infarct-related artery immediately after thrombolytic therapy. 2. PTCA of the stenotic infarct-related artery within 48 hours of receiving a thrombolytic agent in asymptomatic patients without evidence of ischemia.

Secondary Prevention

Management of Lipids

Class I

1. The AHA Step II diet, which is low in saturated fat and cholesterol (less than 7% of total calories as saturated fat and less than 200 mg/d cholesterol), should be instituted in all patients after recovery from AMI.

2. Paties with LDL cholesterol levels greater than 125 mg/dL despite the AHA Step II diet should be placed on drug therapy with the goal of reducing LDL to less than 100 mg/dL.

3. Patients with normal plasma cholesterol levels who have a high-density lipoprotein (HDL) cholesterol level less than 35 mg/dL should receive nonpharmacological therapy (eg, exercise) designed to raise it.

Class IIa

1. Drug therapy may be added to diet in patients with LDL cholesterol levels less than 130 mg/dL but greater than 100 mg/dL after an appropriate trial of the AHA Step II diet alone.*¹⁰

2. Patients with normal total cholesterol levels but HDL cholesterol less than 35 mg/dL despite diet and other non-pharmacological therapy may be started on drugs such as niacin to raise HDL levels.

⇓.

Long-Term β-Adrenoceptor Blocker Therapy in Survivors of Myocardial Infarction

Class IIa

1. Low-risk patients without a clear contraindication to β-adrenoceptor blocker therapy. ⇓.

Anticoagulants

Long-Term Anticoagulation After AMI

Class I

1. For secondary prevention of MI in post-MI patients unable to take daily aspirin.†¹¹ 2. Post-MI patients in persistent AF. 3. Patients with LV thrombus.

Class IIa

1. Post-MI patients with extensive wall motion abnormalities. 2. Patients with paroxysmal AF.

Class IIb

1. Post-MI patients with severe LV systolic dysfunction with or without CHF.

Estrogen Replacement Therapy and Myocardial Infarction

⇓