🚨 Acute Coronary Syndrome
Overview
A spectrum of conditions including unstable angina, NSTEMI, and STEMI, resulting from acute myocardial ischaemia due to reduced coronary blood flow. It presents with chest pain and can lead to myocardial damage and life-threatening arrhythmias. Prompt diagnosis and reperfusion are vital.
Recognition
Sudden onset of central crushing chest pain, often radiating to the left arm, jaw, or back, not relieved by rest. May be associated with dyspnoea, nausea, vomiting, diaphoresis, and palpitations. Atypical presentations are common in women, elderly, and diabetics.
Initial Assessment (ABCDE)
Assess airway and breathing, noting respiratory rate and oxygen saturation. Evaluate circulation (heart rate, blood pressure, capillary refill time). Assess disability (GCS) and expose to check for pallor or diaphoresis. Obtain a 12-lead ECG immediately.
Red Flags
Persistent or worsening chest pain despite initial therapy, new or worsening haemodynamic instability (hypotension, shock), new arrhythmias, signs of heart failure (crackles, S3 gallop), or evolving ECG changes (e.g., new ST elevation).
Investigations
Immediate 12-lead ECG is crucial to differentiate STEMI from NSTEMI/unstable angina. Cardiac troponins (high-sensitivity) are essential, measured on presentation and repeated at 1-3 hours. FBC, U&Es, LFTs, and coagulation screen. Chest X-ray to rule out other causes of chest pain.
Immediate Management
Administer oxygen if hypoxic (saturations <94%). Give aspirin immediately. Consider nitrates for pain relief. For STEMI, immediate reperfusion therapy (primary PCI or fibrinolysis) is paramount. For NSTEMI/unstable angina, risk stratification guides management, including antiplatelets and anticoagulants. Pain relief with opioids if needed.
Escalation Triggers
Any patient with suspected ACS, especially STEMI, requires immediate senior medical and cardiology input. Haemodynamic instability, persistent arrhythmias, or signs of cardiogenic shock necessitate urgent ICU review and potential advanced interventions.
MLA High-Yield Notes
Time is myocardium! For STEMI, the goal is reperfusion within 90-120 minutes. Remember the 'MONA' acronym (Morphine, Oxygen, Nitrates, Aspirin) but prioritise aspirin and reperfusion. Troponin levels rise later, so ECG is the initial diagnostic tool. Atypical presentations are common; maintain a high index of suspicion.
References
- NICE Guideline CG172: Acute coronary syndromes
- Resuscitation Council UK: Adult Advanced Life Support Guidelines
- European Society of Cardiology Guidelines for the management of acute coronary syndromes