What is the guideline therapy for a patient experiencing a heart attack?

Guideline Heart Attack Therapy

For acute myocardial infarction, immediate treatment consists of aspirin 162-325 mg, oxygen if hypoxic, intravenous nitroglycerin for ongoing chest pain, and morphine for analgesia, followed by urgent reperfusion therapy with either primary PCI or fibrinolytic therapy depending on time to treatment and availability. 1

Immediate Pre-Hospital and Emergency Management

Initial Medications (First Minutes)

• Aspirin 162-325 mg should be administered immediately upon recognition of acute MI, either by emergency medical services or the patient themselves, as it reduces mortality and has synergistic effects with fibrinolytic therapy 1
• Opioid analgesia with intravenous morphine sulfate (up to 10 mg) or diamorphine (up to 5 mg) should be titrated against pain using small repeated doses, along with an antiemetic such as metoclopramide 10 mg 1
• Sublingual nitroglycerin (spray or tablet) for ongoing chest pain, unless hypotension is present 1
• Oxygen therapy should be administered to patients with hypoxia or evidence of heart failure 1

Reperfusion Strategy Selection

The choice between fibrinolytic therapy and primary PCI depends critically on time from symptom onset and availability:

• If primary PCI is available within 90 minutes of first medical contact, this is the preferred reperfusion strategy 1
• If PCI is not rapidly available and presentation is within 6 hours of symptom onset, fibrinolytic therapy should be initiated immediately, preferably in the pre-hospital setting 2
• ECG confirmation is mandatory before fibrinolysis: ST-segment elevation or new left bundle branch block indicates benefit, while normal ECG or ST-depression shows no benefit and increases harm 1

Fibrinolytic Therapy Protocol (When PCI Unavailable)

Primary Thrombolytic Agent

Use a fibrin-specific agent as first-line therapy: 2

• Tenecteplase, alteplase, or reteplase are recommended over streptokinase 2
• Alteplase is administered as an infusion over approximately 90 minutes 2
• For patients ≥75 years, consider half-dose tenecteplase to reduce bleeding risk 2

Mandatory Adjunctive Antiplatelet Therapy

Dual antiplatelet therapy is essential with fibrinolysis: 2, 3

• Aspirin 75-325 mg daily should be continued indefinitely 1
• Clopidogrel loading dose of 300 mg for patients <75 years, followed by 75 mg daily 2, 3
• Clopidogrel should continue for at least 14 days, with consideration for up to 12 months 2

Mandatory Anticoagulation

All patients receiving fibrinolytic therapy require anticoagulation: 2

• Enoxaparin is preferred over unfractionated heparin (UFH) 2
• UFH alternative: weight-adjusted IV bolus followed by infusion, continued until revascularization or for hospital duration up to 8 days 2
• Fondaparinux may be used specifically for patients receiving streptokinase, but should never be used as sole anticoagulation during PCI due to catheter thrombosis risk 2

Critical Timing

The call-to-needle time should be ≤90 minutes, ideally ≤60 minutes 1

• Greatest mortality benefit occurs when treatment is given within 6 hours of symptom onset 2
• Efficacy decreases substantially after 3 hours, making primary PCI increasingly preferable 2

Post-Reperfusion Acute Management

Complications Monitoring and Treatment

Patients require close observation for prompt recognition of complications: 1

• Recurrent chest pain from pericarditis: high-dose aspirin 650 mg every 4-6 hours 1
• Recurrent ischemic chest pain: intravenous nitroglycerin, analgesics, and antithrombotic medications (aspirin, heparin), with consideration for coronary angiography and revascularization 1
• Heart failure: intravenous furosemide and afterload-reducing agents 1
• Cardiogenic shock: intra-aortic balloon pump support and emergency coronary angiography followed by PTCA or CABG 1
• Right ventricular infarction with hypotension: vigorous intravascular volume expansion with normal saline and inotropic agents if hypotension persists 1

Long-Term Secondary Prevention (Indefinite Duration)

Essential Medications

All post-MI patients require lifelong medical therapy: 1

• Aspirin 75-325 mg daily indefinitely 1
• Beta-blockers started in all post-MI patients and continued indefinitely, unless contraindicated 1
• ACE inhibitors for all patients indefinitely post-MI, started early in high-risk patients (anterior MI, previous MI, Killip class II with S3 gallop, rales, or radiographic CHF), with consideration for chronic therapy in all other patients with coronary or vascular disease 1

Lipid Management

Aggressive lipid lowering is mandatory: 1

• Target LDL <100 mg/dL using statin or resin therapy 1
• If LDL ≥130 mg/dL despite diet, intensify drug therapy 1
• If triglycerides 200-499 mg/dL, consider fibrate or niacin after LDL-lowering therapy 1
• If triglycerides ≥500 mg/dL, consider fibrate or niacin before LDL-lowering therapy 1

Lifestyle Modifications

Comprehensive risk factor modification is essential: 1

• Smoking cessation is mandatory 1
• Exercise prescription: minimum 30-60 minutes of activity daily or at least 3-4 times weekly (walking, jogging, cycling), with medically supervised programs for moderate-to-high-risk patients 1
• Weight management: target BMI 18.5-24.9 kg/m², with waist circumference <40 inches in men and <35 inches in women when BMI ≥25 kg/m² 1
• Diet low in saturated fat and cholesterol 1

Pre-Discharge Risk Stratification

Exercise testing should be performed before or shortly after discharge: 1

• Submaximal testing at 4-7 days or symptom-limited testing at 10-14 days 1
• Purpose: assess functional capacity, evaluate medical regimen efficacy, and stratify risk for subsequent cardiac events 1

Important Clinical Pitfalls

• Never use fondaparinux as sole anticoagulation during PCI - it increases catheter thrombosis risk and requires additional UFH or bivalirudin 2
• Do not give thrombolytics to patients with normal ECG or ST-depression - no benefit is seen and harm may result from treating MI mimics 1
• Aspirin doses >100 mg in patients on dual antiplatelet therapy may reduce efficacy and increase bleeding risk compared to 75-81 mg daily 4
• CYP2C19 poor metabolizers (2% of Whites, 4% of Blacks, 14% of Chinese) have reduced clopidogrel effectiveness and may require alternative antiplatelet therapy 3