Acute Coronary Syndrome

What Is Acute Coronary Syndrome?

Acute coronary syndrome (ACS) is an umbrella term for conditions caused by sudden, reduced blood flow to the heart muscle: ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), and unstable angina. Patients typically present with substernal chest pressure or pain (often radiating to the arm, jaw, or back), diaphoresis, nausea, and shortness of breath — though presentation can be atypical in women, diabetics, and older adults. For fire-based EMS providers, the priority is early recognition, a 12-lead ECG within 10 minutes of patient contact, and rapid transport to a PCI-capable facility, since 'time is muscle' once ischemia begins.

Why Acute Coronary Syndrome Matters on the Fireground

ACS is one of the most common life-threatening medical calls a fire-EMS crew will run, and it's also an occupational hazard within the fire service itself — cardiac events remain a leading cause of firefighter line-of-duty deaths. Crews need to recognize ACS quickly in patients, act fast on STEMI protocols, and stay alert to the same warning signs in themselves and their partners after physically demanding calls.

Relevant NFPA Standards

• AHA Guidelines: Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
• NFPA 455: Standard for Emergency Medical Services (EMS)

Field Procedures & Tactical Steps

1. Perform a primary assessment; apply supplemental oxygen only if SpO2 is below 90%.
2. Obtain a 12-lead ECG as early as possible and transmit it to medical direction or the PCI-receiving facility to activate the cath lab en route.
3. Give 324 mg of chewable, non-enteric aspirin (four 81 mg tablets) unless contraindicated by allergy, active bleeding, or recent GI hemorrhage.
4. Assist with sublingual nitroglycerin (0.4 mg), repeated every 5 minutes as needed, only if systolic blood pressure remains above 100 mmHg and there is no suspicion of right-sided MI or recent PDE-5 inhibitor use.
5. Establish IV access, place on a cardiac monitor, and reassess vitals frequently for arrhythmias or hemodynamic decline en route.

Common Context & Application

Encountered on prehospital EMS calls involving chest pain, sudden shortness of breath, or collapse — and occasionally as an occupational medical concern for firefighters during or after strenuous fireground operations.

Frequently Asked Questions about Acute Coronary Syndrome