What is the initial treatment for chest pain suspected to be of cardiac origin?

Initial Treatment for Chest Pain Suspected to be of Cardiac Origin

Call 9-1-1 immediately and administer aspirin 325 mg (or 2-4 baby aspirins of 81 mg each) chewed and swallowed while waiting for EMS, provided the patient has no aspirin allergy or recent bleeding. 1

Immediate Actions (First 5 Minutes)

• Activate EMS immediately rather than attempting self-transport, as patients with suspected acute coronary syndrome have a 1.5% risk of cardiopulmonary arrest before hospital arrival 1
• Administer aspirin as soon as cardiac origin is suspected: one 325-mg tablet or 2-4 low-dose 81-mg tablets, chewed and swallowed 1
• Early aspirin administration (within first few hours) significantly reduces mortality from myocardial infarction compared to delayed administration 1, 2
• Do not give aspirin if chest pain does not suggest cardiac origin, if uncertain about the diagnosis, or if the patient has aspirin allergy or contraindications such as recent bleeding 1

While Waiting for EMS (Within 10 Minutes)

• Position the patient at rest in a comfortable position to minimize cardiac workload 1
• Obtain 12-lead ECG within 10 minutes of first medical contact if equipment and trained personnel are available 1
• Monitor vital signs continuously including blood pressure, heart rate, and oxygen saturation 1
• Assess for high-risk features suggesting alternative diagnoses like aortic dissection (sudden tearing pain radiating to back, pulse deficits, blood pressure differentials >20 mmHg between arms) - if present, do not give aspirin or anticoagulants 3

Key Clinical Indicators of Cardiac Origin

Look specifically for these features that suggest myocardial infarction rather than other causes 1:

• Shortness of breath accompanying chest discomfort
• Nausea or diaphoresis (sweating)
• Pain radiating to arm(s) or back
• Pressure, squeezing, or tightness quality of pain

Common Pitfalls to Avoid

• Do not delay EMS activation to "see if it gets better" - median delay from symptom onset to treatment in successful outcomes is 8 hours, but earlier is better 4
• Do not withhold aspirin in clear cardiac presentations due to theoretical bleeding concerns - the mortality benefit far outweighs the small bleeding risk in true myocardial infarction 1, 2
• Do not give aspirin for undifferentiated chest pain without features suggesting cardiac origin, as there is no evidence of benefit and potential for harm 1
• Women may present atypically with less typical chest pain and more generalized symptoms - maintain high suspicion 3
• Diabetic patients may have blunted pain perception due to autonomic dysfunction 3

What NOT to Give

• Gabapentin has no role in acute cardiac chest pain as it does not address underlying ischemia 5
• Beta-blockers (like metoprolol) should only be administered by EMS or hospital personnel after hemodynamic stability is confirmed, not by first aid providers 4
• Nitroglycerin administration is an EMS/hospital decision, not a first aid intervention 6

EMS and Hospital Handoff

• EMS should transmit 12-lead ECG to receiving hospital if STEMI is identified 1
• Target door-to-balloon time ≤90 minutes (preferred) or ≤120 minutes (acceptable) for STEMI 1
• Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) will be initiated by hospital providers 6