What is the treatment for myocardial infarction (heart attack)?

Treatment for Myocardial Infarction (Heart Attack)

The immediate treatment for myocardial infarction requires rapid assessment within 10 minutes of arrival to the emergency department, administration of oxygen, sublingual nitroglycerin (if no hypotension or extreme heart rates), aspirin 160-325mg, adequate analgesia with morphine, and immediate reperfusion therapy for ST-elevation MI or new LBBB. 1, 2

Initial Emergency Management

• Evaluation should be completed within 10 minutes of arrival to the emergency department, with no more than 20 minutes elapsing before assessment 1, 2
• Obtain a 12-lead ECG immediately to identify ST-segment elevation (≥1mV) in contiguous leads or new left bundle branch block 1, 2
• Administer oxygen via nasal prongs, especially for patients who are breathless 1, 2
• Give sublingual nitroglycerin unless systolic BP <90mmHg or heart rate <50 or >100bpm 1, 2
• Administer aspirin 160-325mg orally (chewable for faster absorption) 1, 2
• Provide adequate analgesia with intravenous morphine (4-8mg initially with additional 2mg doses at 5-minute intervals) or meperidine, with concurrent antiemetics 1, 2
• Establish continuous cardiac monitoring immediately 2

Reperfusion Therapy

• For patients with ST-elevation MI or new LBBB, immediate reperfusion therapy is essential 1, 2
• Thrombolytic therapy provides greatest benefit when initiated within 6 hours of symptom onset, with maximum benefit in the first hour (35 lives saved per 1000 patients treated) 1, 2
• Primary percutaneous transluminal coronary angioplasty (PTCA) is an alternative to thrombolysis if performed in a timely fashion by skilled personnel with access to emergency CABG 1
• For patients receiving alteplase (tPA), intravenous heparin should be continued for an additional 48 hours 1

Medication Management After Initial Treatment

• Continue aspirin 160-325mg daily indefinitely 1
• Administer intravenous β-adrenergic blockers followed by oral therapy, unless contraindicated 1, 3
• Continue intravenous nitroglycerin for 24-48 hours after hospitalization 1
• Consider ACE inhibitors, particularly for patients with anterior MI or left ventricular dysfunction 1
• Avoid calcium channel blockers as they have not been shown to reduce mortality and may be harmful in certain patients 1

Management of Complications

• For heart failure: administer diuretics (usually intravenous furosemide) and afterload-reducing agents 1
• For cardiogenic shock: consider insertion of an intra-aortic balloon pump and emergency coronary angiography, followed by PTCA or CABG 1
• For right ventricular infarction: provide vigorous intravascular volume expansion with normal saline and inotropic agents if hypotension persists 1
• For recurrent chest pain due to pericarditis: administer high-dose aspirin (650mg every 4-6 hours) 1
• For recurrent chest pain due to ischemia: treat with intravenous nitroglycerin, analgesics, and antithrombotic medications 1

Hospital Course and Discharge Planning

• Patients with uncomplicated MI can sit out of bed late on the first day and begin ambulation the next day 1
• Those with heart failure, shock, or serious arrhythmias should have more gradual physical activity progression 1
• Before discharge, patients should undergo exercise testing (submaximal at 4-7 days or symptom-limited at 10-14 days) 1
• Long-term management should include aspirin, β-blockers, and ACE inhibitors indefinitely 1
• Lipid management is essential, with a goal of reducing LDL to less than 100 mg/dL 1
• Smoking cessation, dietary modifications, and participation in cardiac rehabilitation are crucial 1

Common Pitfalls to Avoid

• Delaying ECG assessment beyond 10 minutes of arrival 1, 2
• Withholding aspirin administration while waiting for definitive diagnosis 2, 4
• Administering thrombolytics to patients without ST-elevation or with contraindications 1, 2
• Failing to provide adequate analgesia, which can increase sympathetic activation 2
• Delaying reperfusion therapy, as benefit is time-dependent with greatest advantage in the first hour 1, 2, 5
• Underestimating the importance of patient education to reduce delays in seeking treatment for future events 4, 6