Emergency Management of Acute Coronary Syndromes in Adults

Initial Assessment

• Obtain a 12‑lead electrocardiogram within 10 minutes of first medical contact to classify the presentation as ST‑elevation or non‑ST‑elevation ACS. (European Society of Cardiology guideline) 1
• Establish intravenous access and draw initial laboratory studies—including high‑sensitivity troponin, a complete blood count, and a basic metabolic panel—at presentation. (European Society of Cardiology guideline) 2
• Provide supplemental oxygen (2–4 L/min) only when oxygen saturation is < 90 % or the patient is dyspneic or shows signs of heart failure. (European Society of Cardiology guideline) 3
• Administer intravenous morphine 4–8 mg, with additional 2 mg doses every 5 minutes as needed for pain relief, because uncontrolled pain increases sympathetic drive and myocardial workload. (European Society of Cardiology guideline) 4

ST‑Elevation Myocardial Infarction (STEMI) Management

• Activate the catheterisation laboratory immediately and achieve primary percutaneous coronary intervention (PCI) within 120 minutes of diagnosis; this strategy lowers in‑hospital mortality from 9 % to 7 %. (European Society of Cardiology guideline) 2
• Do not await troponin results before initiating reperfusion therapy in patients with ST‑segment elevation or new left bundle‑branch block. (European Society of Cardiology guideline) 2

Non‑ST‑Elevation ACS Management

• Give aspirin 75–150 mg daily (if not already administered) as part of antiplatelet therapy. (European Society of Cardiology guideline) 5
• Give a clopidogrel loading dose of 300–600 mg in addition to aspirin. (European Society of Cardiology guideline) 5
• Administer low‑molecular‑weight heparin (e.g., enoxaparin) or unfractionated heparin for anticoagulation. (European Society of Cardiology guideline) 5
• Start a beta‑blocker unless contraindicated by heart failure, bradycardia, or hypotension. (European Society of Cardiology guideline) 5
• Provide oral or intravenous nitrates for ongoing chest pain when systolic blood pressure permits. (European Society of Cardiology guideline) 5
• Perform serial electrocardiograms whenever the patient experiences recurrent chest pain. (European Society of Cardiology guideline) 5

Risk Stratification and Early Invasive Strategy

• Identify high‑risk features—recurrent chest pain or dynamic ST changes, elevated troponin, haemodynamic instability, major ventricular arrhythmias, and diabetes mellitus—that mandate coronary angiography within 24–48 hours. (European Society of Cardiology guideline) 5
• Early invasive evaluation of high‑risk patients reduces mortality from 6.5 % to 4.9 %. (European Society of Cardiology guideline) 1
• Patients without high‑risk features and with normal serial troponins may undergo stress testing or coronary CT angiography before discharge or as an outpatient strategy. (American College of Cardiology guideline) 6

Diagnostic Adjuncts

• Consider cocaine use as a precipitating factor for ACS in the appropriate clinical context. (European Society of Cardiology guideline) 3
• Consider spontaneous coronary artery dissection, especially in patients with minimal traditional risk factors. (European Society of Cardiology guideline) 4
• Perform a two‑dimensional echocardiogram within 24–48 hours to evaluate left‑ventricular function, detect regional wall‑motion abnormalities, and rule out alternative life‑threatening diagnoses such as aortic dissection, pericardial effusion, or pulmonary embolism. (European Society of Cardiology guideline) 4

Monitoring and Observation

• Observe patients for a minimum of 6–12 hours with continuous telemetry, repeat ECGs for any recurrent symptoms, and a repeat troponin measurement. (European Society of Cardiology guideline) 5
• Document haemodynamic stability—including blood pressure, heart rate, presence of a third heart sound, and pulmonary rales—throughout the observation period. (European Society of Cardiology guideline) 2

Management of Severe Sudden Onset Chest Pain

Initial Assessment and Actions

• The American College of Cardiology recommends that patients experiencing severe sudden onset chest pain should be instructed to call emergency services immediately, especially when the discomfort is moderate to severe or sustained 7, 8
• The American College of Cardiology advises healthcare providers receiving calls about chest pain to direct patients to seek immediate medical attention, as evaluation cannot be performed via telephone 9, 10
• Patients with known coronary artery disease who experience worsening or recurrent symptoms should proceed rapidly to an emergency department equipped to perform prompt reperfusion therapy, as recommended by the American College of Cardiology 7, 8
• Upon arrival at a healthcare facility, the patient should be placed on cardiac monitor immediately with emergency resuscitation equipment nearby, according to the American College of Cardiology 11

Immediate Management Protocol

• The American College of Cardiology recommends performing and evaluating ECG within 10 minutes of arrival to identify potential ST-elevation myocardial infarction or other acute cardiac conditions 11
• Obtaining vital signs and a focused history is crucial to identify potential causes of chest pain, as recommended by the American College of Cardiology 11
• Administering fast-acting aspirin (250-500mg) is recommended if not contraindicated, according to the American College of Cardiology 11

Transport Decisions

• The American College of Cardiology suggests that every community should have a written protocol guiding EMS personnel in determining where to take patients with suspected or confirmed acute coronary syndrome 7, 9
• Patients with suspected acute coronary syndrome should generally be taken to the nearest appropriate hospital, as recommended by the American College of Cardiology 7, 10
• Patients with known ST-elevation myocardial infarction and/or cardiogenic shock should be sent directly to hospitals with interventional and surgical capability, according to the American College of Cardiology 7, 9

Differential Diagnosis Considerations

• Chest pain may indicate various life-threatening conditions, including myocardial infarction, unstable angina, aortic dissection, pulmonary embolism, or pneumothorax, as noted by the American College of Cardiology 11
• Sudden onset of ripping chest pain with radiation to the back is highly suspicious for acute aortic syndrome, according to the American College of Cardiology 12

Special Considerations

• Elderly patients or those with diabetes may present with atypical symptoms and require heightened vigilance, as recommended by the American College of Cardiology 11, 12
• In a large study, one-third of patients with chest pain suspected to be of cardiac origin had a final diagnosis of myocardial infarction, one-third had unstable angina, and one-third had a noncardiac cause, according to the American College of Cardiology 7, 8

Important Pitfalls to Avoid

• The American College of Cardiology advises against relying solely on pain severity to determine urgency, as severity is a poor predictor of imminent complications such as cardiac arrest 11
• Delaying treatment while waiting for definitive diagnosis in patients with red flags should be avoided, as recommended by the American College of Cardiology 11
• Dismissing symptoms over the telephone is not recommended, as proper evaluation requires physical examination, ECG, and appropriate blood tests, according to the American College of Cardiology 7, 8