Acute Coronary Syndrome (ACS): A Guide for Emergency Physicians

Acute Coronary Syndrome (ACS) is a spectrum of urgent, potentially life-threatening heart conditions resulting from ischemia due to reduced coronary blood flow. This guide is crafted to help you, a junior doctor, navigate the essentials of history-taking, examination, investigation, and management of ACS in the Emergency Department (ED). Your approach should be systematic and efficient—so you can quickly identify patients needing immediate intervention.

History Taking: Key Questions to Ask

Start with targeted questions to identify the risk and symptoms of ACS. Here’s a structured way to uncover important information:

Presenting Symptoms:

·       “Can you describe your chest pain?” (Assess for classic ACS pain, usually described as a heavy, crushing, or squeezing central chest pain, often radiating to the left arm, neck, jaw, or back.)

·       “When did the pain start, and how long did it last?” (ACS pain often lasts longer than angina, typically >20 minutes, and may not improve with rest.)

·       “Did anything trigger the pain or make it worse?” (ACS pain can occur at rest or with exertion. Check if it's relieved by rest or nitrates.)

·       “Have you had any other symptoms, like nausea, sweating, or shortness of breath?” (Autonomic symptoms such as diaphoresis, nausea, or vomiting can indicate ACS.)

Risk Factors for ACS:

·       “Do you have any history of heart disease?” (Personal or family history of coronary artery disease increases risk.)

·       “Are you a smoker?” (Smoking significantly increases ACS risk.)

·       “Do you have diabetes, high blood pressure, or high cholesterol?” (These comorbidities are common in ACS patients.)

·       “Have you had previous chest pain, angina, or heart attacks?” (Previous cardiac events increase risk.)

·       “What medications do you take, and do you use recreational drugs?” (Ask about current medications, aspirin use, and use of drugs like cocaine, which can induce vasospasm.)

Examination Findings to Look For

Conduct a focused physical examination to gather clues that either confirm ACS or guide you to other differentials.

General Observations:

·       Appearance: Note if the patient appears distressed, pale, or diaphoretic—signs that suggest severe ischemia.

·       Vital Signs: Check blood pressure in both arms, pulse rate, respiratory rate, and temperature. Hypotension may suggest cardiogenic shock, while tachycardia or hypertension could imply stress or pain.

Cardiovascular Exam:

·       Heart Sounds: Listen for S3 (suggesting heart failure) or murmurs (e.g., new mitral regurgitation due to papillary muscle dysfunction).

·       JVP: Raised JVP may indicate right-sided heart strain or heart failure.

·       Peripheral Pulses: Check for signs of poor perfusion like weak pulses or delayed capillary refill.

Respiratory Exam:

·       Breath Sounds: Assess for crackles, which may indicate pulmonary edema if the patient has left ventricular failure.

Other Observations:

·       Abdominal Examination: Rule out abdominal causes of pain.

·       Peripheral Edema: Look for signs of fluid overload.

Investigations to Order

Quickly initiate diagnostic tests to assess myocardial damage and rule out differentials. Time is myocardium in ACS, so act swiftly.

ECG (Electrocardiogram):

·       Obtain an ECG within 10 minutes of the patient’s arrival.

·       Look for ST-segment elevation (indicative of STEMI) or ST-segment depression/T-wave inversions (possible NSTEMI or unstable angina).

·       Repeat ECGs every 15-30 minutes if symptoms persist, as early changes can be subtle.

Cardiac Biomarkers:

·       Troponins (Troponin I or T): These are the most specific markers of myocardial injury. Troponin elevation confirms myocardial damage, but a single normal value doesn’t rule out ACS—repeat after 3-6 hours if necessary.

·       Other markers (e.g., CK-MB) are less specific and are rarely required with high-sensitivity troponins.

Chest X-ray (CXR):

·       Obtain a CXR to rule out other causes of chest pain (e.g., pneumothorax, pneumonia, or aortic dissection).

·       Also helpful to assess for signs of heart failure like pulmonary congestion.

Other Tests:

·       Blood tests: Full blood count (FBC), renal function, electrolytes, and glucose levels.

·       BNP or NT-proBNP: Consider if heart failure is suspected, though not always essential for initial ACS diagnosis.

·       Echocardiogram: May be needed to assess cardiac function or complications (e.g., wall motion abnormalities) but is often done later in stable patients.

Management Plan

Management of ACS should be prompt, aiming to restore coronary perfusion, relieve pain, and prevent complications. Tailor your approach based on whether the patient is having a STEMI, NSTEMI, or unstable angina.

Immediate Management (First 10 minutes):

·       Oxygen: Only give if oxygen saturation is <90% or the patient is in respiratory distress.

·       Aspirin 300 mg: Chewed and swallowed, as it reduces mortality by inhibiting platelet aggregation.

·       Nitroglycerin: Sublingual nitroglycerin (GTN) for pain relief, unless contraindicated by hypotension or recent PDE5 inhibitor use.

·       Morphine: If pain persists despite nitrates, consider IV morphine (use caution in hypotensive patients).

·       Anti-platelet therapy: In addition to aspirin, give a P2Y12 inhibitor (e.g., clopidogrel, ticagrelor) unless contraindicated.

Further Management Based on Diagnosis:

·       STEMI:

o   Primary PCI (Percutaneous Coronary Intervention): Gold standard within 90 minutes if available; refer immediately.

o   Thrombolysis: If PCI is unavailable within 120 minutes, consider thrombolytic therapy, especially if the patient presents early (within 12 hours of symptom onset).

·       NSTEMI/Unstable Angina:

o   Risk Stratification: Use scores like GRACE or TIMI to determine if urgent invasive management is needed.

o   Anticoagulation: Use agents like low-molecular-weight heparin or fondaparinux, especially if PCI is planned.

o   Beta-blockers: Often given to reduce heart rate and myocardial oxygen demand unless contraindicated (e.g., bradycardia or hypotension).

Key Takeaways

·       Act Fast: Time is crucial; initiate treatment quickly, especially for STEMI patients.

·       Identify Risk Factors: A thorough history can reveal vital clues, and ECG + troponin testing confirm your diagnosis.

·       Know the Pathway: Follow ACS protocols meticulously to ensure rapid intervention and optimal patient outcomes.

·       Always Educate: Ensure patients understand the importance of secondary prevention to reduce recurrence.

Remember, your structured approach to ACS can save lives. A confident, calm demeanor, combined with efficient management, will provide the best outcomes for your patients.

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