What is the initial emergency treatment for a heart attack?

Emergency Treatment for Heart Attack

The immediate emergency treatment for a heart attack centers on rapid defibrillation capability, aspirin administration, adequate analgesia with intravenous opioids, oxygen if hypoxic, and thrombolytic therapy within 90 minutes of calling for help—or primary percutaneous coronary intervention (PCI) if available within 30 minutes of hospital arrival. 1

Immediate Pre-Hospital Actions

Call emergency services immediately rather than attempting self-transport, as ambulances equipped with defibrillators and trained personnel significantly improve survival. 1

• All patients with chest pain require an emergency response with a vehicle containing a defibrillator and staff trained in its use. 1
• The most critical period is the very early phase when patients are liable to cardiac arrest, making immediate access to defibrillation life-saving. 1
• Paramedic-staffed ambulances should be equipped with defibrillators, with at least one person trained in advanced life support. 1

Initial Medical Treatment (First Contact)

Aspirin

Administer aspirin 160-325 mg orally immediately upon first medical contact, even before ECG confirmation. 2, 3

Pain Relief

Intravenous diamorphine (or morphine) with an antiemetic is the analgesic of choice for acute myocardial infarction. 1

• Adequate analgesia is essential and should not be delayed. 1
• Meperidine can be used as an alternative opioid analgesic. 3

Oxygen Therapy

Provide oxygen only if arterial oxygen saturation is <90%. 2

• Routine oxygen administration is not recommended for non-hypoxic patients. 2

Nitroglycerin

Give sublingual nitroglycerin unless systolic blood pressure is <90 mmHg or heart rate is <50 or >100 bpm. 2

• Nitroglycerin helps treat chest pain and reduces myocardial oxygen demand. 1, 3

Critical Time Targets

The goal is thrombolytic treatment within 90 minutes of alerting medical services (call-to-needle time) or door-to-needle time ≤30 minutes once in hospital. 1, 2

Why Time Matters

• Treatment within the first hour saves 65 lives per 1,000 patients treated. 1
• Treatment in the second or third hour saves 27 lives per 1,000 patients. 1
• Treatment in the fourth to sixth hour saves only 25 lives per 1,000 patients. 1
• This dramatic time-dependent benefit makes every minute count. 4

Hospital Emergency Department Protocol

Immediate Assessment (Within 10 Minutes)

Obtain a 12-lead ECG within 10 minutes of arrival to identify ST-segment elevation ≥1 mm in contiguous leads or new left bundle branch block. 1, 2

• Patients with clear ST-elevation or left bundle branch block should enter a "fast-track" system. 1
• ECG monitoring should begin immediately upon entry to detect life-threatening arrhythmias. 1

Reperfusion Strategy Decision

Primary PCI is the preferred reperfusion strategy when available without excessive delay. 1, 2

• For patients with cardiac arrest and ST-segment elevation, primary PCI is specifically recommended. 2
• If PCI is not immediately available, administer thrombolytic therapy (tissue plasminogen activator, streptokinase, or urokinase) within 3 hours of symptom onset. 3

Door-to-needle time for fibrinolytic therapy must be ≤30 minutes. 2

Additional Medications

Beta-Blockers

For hemodynamically stable patients, initiate intravenous metoprolol (three 5 mg bolus injections at 2-minute intervals), followed by oral metoprolol 50 mg every 6 hours starting 15 minutes after the last IV dose. 5

• Monitor blood pressure, heart rate, and ECG during IV administration. 5
• Beta-blockers reduce cardiovascular mortality in definite or suspected acute myocardial infarction. 5
• Do not administer if patient shows signs of hypotension, bradycardia, peripheral shock, or significant pulmonary congestion. 5

ACE Inhibitors

Long-term ACE inhibitor therapy (4-5 years) provides benefit even without ventricular dysfunction. 1

Critical Pitfalls to Avoid

Patient Delay

The median delay from symptom onset to seeking care is 2 hours, with many patients waiting much longer. 6, 7

• Patients delay because they think symptoms will resolve, symptoms aren't severe enough, or they attribute symptoms to another cause. 7
• Up to 30% of patients with myocardial infarction have known coronary disease—these high-risk patients should receive explicit instructions on when to call for help. 1

Atypical Presentations

Recognize that throat pain, jaw pain, neck pain, fatigue, dyspnea, or syncope can represent myocardial infarction, especially in elderly patients, women, and diabetics. 8, 2

• Atypical symptoms are associated with delayed diagnosis and worse outcomes. 8
• Pain lasting >20 minutes that doesn't respond to nitroglycerin is high-risk regardless of location. 8, 2

Transportation Errors

Patients should not self-transport or wait for their general practitioner if this causes delay. 1, 7

• The main reason patients don't call 911 is thinking self-transport will be faster due to proximity to hospital—this is a dangerous misconception. 7
• Ambulance transport provides immediate access to defibrillation and advanced life support. 1

Monitoring and Ongoing Care

Continuous ECG monitoring should continue for at least 24 hours to detect arrhythmias. 1

• More prolonged monitoring is appropriate for patients with heart failure, shock, or serious arrhythmias. 1
• Arterial pressure monitoring should be undertaken in patients with cardiogenic shock. 1

Special Populations

Cardiogenic Shock

Immediate revascularization of the infarct-related coronary artery is the only treatment supported by randomized trials for cardiogenic shock after myocardial infarction. 9

• Culprit lesion-only revascularization is superior to multivessel PCI (45.9% vs 55.4% for 30-day death or kidney replacement therapy). 9
• Despite lack of trial evidence, mechanical circulatory support devices are frequently used. 9

Cardiac Arrest Survivors

Resuscitated cardiac arrest patients with ECG consistent with STEMI should receive primary PCI. 2

• Targeted temperature management is indicated for patients who remain unresponsive after resuscitation. 2