Immediate Management of Chest Heaviness

Call emergency services (9-1-1) immediately and chew 162–325 mg aspirin while waiting for transport—do not self-drive to the hospital. 1, 2, 3

Pre-Hospital Actions (First 5 Minutes)

If you have previously been prescribed nitroglycerin, take ONE sublingual dose; if chest discomfort is unimproved or worsening 5 minutes after taking nitroglycerin, call 9-1-1 immediately. 1, 2
Patients should call emergency services rather than self-transport because approximately 1 in 300 patients with chest pain transported by private vehicle experiences cardiac arrest en route. 1, 2, 3
Chew aspirin 162–325 mg immediately while waiting for ambulance—this is the single most important early drug therapy for suspected heart attack. 2, 3
Sit down and remain still to minimize oxygen demand on the heart. 4

A 12-lead ECG must be obtained within 10 minutes of arrival to detect ST-segment elevation ≥1 mm in contiguous leads or new left bundle branch block, which indicates need for immediate reperfusion therapy. 1, 2, 3
Continuous cardiac monitoring with immediate defibrillator availability must be initiated to detect life-threatening arrhythmias. 2, 3
Aspirin 160–325 mg should be administered orally (chewed if possible) if not already given pre-hospital. 2, 3

Sublingual nitroglycerin should be given (up to 3 doses, 5 minutes apart) unless systolic blood pressure is <90 mmHg or heart rate is <50 or >100 bpm. 2, 3, 4
Supplemental oxygen should be provided ONLY if oxygen saturation is <90% or arterial PaO₂ <60 mmHg—routine oxygen in patients with adequate saturation may increase myocardial injury and is classified as harmful. 2, 3
Intravenous morphine may be administered for pain control, titrated to effect, though be aware this may delay absorption of oral antiplatelet medications. 2, 3

Primary percutaneous coronary intervention (PCI) is preferred when it can be performed within 90 minutes of first medical contact (door-to-balloon ≤90 minutes). 2, 3
If primary PCI cannot be achieved within 120 minutes, fibrinolytic therapy should be administered with door-to-needle time ≤30 minutes. 2, 3
The greatest mortality benefit occurs within the first hour of symptom onset, saving approximately 35 lives per 1,000 patients treated—benefit declines markedly after 12 hours. 2, 5
A P2Y12 inhibitor (ticagrelor or prasugrel preferred over clopidogrel) should be administered immediately. 2, 6

Patients with suspected acute coronary syndrome should be transported directly to hospitals with 24-hour catheterization capability, bypassing physician offices and non-PCI-capable facilities. 1, 3, 5
Critically ill patients (cardiac arrest, recurrent ventricular arrhythmias, severe bradycardia, cardiogenic shock) should be taken to facilities equipped with both catheterization labs and cardiac surgery capabilities. 1, 2, 3
Administrative delays such as waiting for insurance authorization must not postpone definitive therapy. 3, 5

Do not wait for cardiac biomarkers in patients with ST-elevation or new left bundle branch block—ECG findings alone warrant immediate reperfusion therapy. 2, 5
Do not withhold nitroglycerin from patients with right ventricular infarction (identified by right-sided ECG leads V1R-V6R in inferior MI), as these patients depend on high preload and nitrates can cause severe hypotension. 2
Do not delay treatment beyond 12 hours from symptom onset unless there is evidence of ongoing ischemia or mechanical complications—reperfusion benefit is minimal after this window. 5
Do not send patients to a physician's office for evaluation—transport directly to an emergency department with cardiac capabilities. 3, 5

Severe epigastric pain, unexplained dyspnea, or indigestion should trigger the full myocardial infarction protocol, especially in elderly patients, women, and diabetics. 2, 3
One-third of MI patients present without chest discomfort; this group has 2.2-fold higher in-hospital mortality (23.3% vs 9.3%). 3