ACS is a time-critical loss of coronary blood flow. Acute coronary syndrome includes unstable angina, NSTEMI and STEMI. Plaque rupture, thrombosis or coronary spasm reduces myocardial oxygen supply; irreversible muscle injury begins quickly. EMTs must recognise typical and atypical symptoms, obtain and interpret an early 12-lead ECG, give appropriate first-line care, avoid harmful delays and activate reperfusion pathways. Use current Uganda cardiac protocols and senior clinician direction.
1. Learning objectives
- Define unstable angina, NSTEMI and STEMI within ACS.
- Recognise typical, atypical and high-risk presentations.
- Perform focused history, ABCDE, 12-lead ECG and serial reassessment.
- Explain aspirin, nitrates, oxygen, analgesia, antithrombotic therapy and reperfusion principles.
- Manage complications including dysrhythmia, cardiogenic shock, pulmonary oedema and cardiac arrest.
- Provide nursing care, secondary prevention, discharge education and referral.
2. What is ACS?
ACS occurs when acute reduction in coronary blood flow causes myocardial ischaemia. Unstable angina has ischaemic symptoms without detectable myocardial necrosis; NSTEMI has myocardial injury without persistent ST elevation; STEMI usually reflects complete or near-complete occlusion with ST elevation or an equivalent pattern. ECG and serial cardiac troponin help classify the syndrome.
| Pattern | Typical finding | Priority |
|---|---|---|
| Unstable angina | New, worsening or rest pain without diagnostic troponin rise. | Monitor, serial ECG/troponin and cardiology assessment. |
| NSTEMI | Ischaemic symptoms and dynamic troponin rise/fall without persistent ST elevation. | Antithrombotic/risk-directed care and early invasive assessment where indicated. |
| STEMI | Persistent ST elevation or equivalent ECG pattern with compatible symptoms. | Immediate reperfusion pathway—PCI if available or approved fibrinolysis. |
3. Risk factors and triggers
- Hypertension, diabetes, smoking, dyslipidaemia, obesity, chronic kidney disease and family history.
- Previous MI, stroke, peripheral arterial disease, known coronary disease or prior stent.
- Stress, infection, anaemia, severe hypoxia, stimulant use, cocaine/amphetamines and intense exertion.
- Pregnancy/postpartum, severe hypertension and spontaneous coronary dissection require specialist input.
4. Symptoms and atypical presentations
| Presentation | Possible symptoms | High-risk clue |
|---|---|---|
| Typical | Pressure, heaviness or tightness in the centre of chest; pain to arm, jaw, back or shoulder. | Persists >10 minutes, occurs at rest or with sweating/nausea. |
| Respiratory | Dyspnoea, fatigue, pulmonary oedema or unexplained reduced exercise tolerance. | Hypoxia, crackles, frothy sputum or inability to lie flat. |
| Gastrointestinal | Epigastric discomfort, nausea, vomiting or indigestion-like pain. | Older adult, diabetic or associated sweating/weakness. |
| Atypical/quiet | Syncope, confusion, weakness, jaw pain or no pain. | Women, older adults and people with diabetes may lack classic chest pain. |
5. Focused history
- Use OPQRST: onset, provocation, quality, region/radiation, severity and time course.
- Ask associated dyspnoea, sweating, nausea, palpitations, syncope, orthopnoea and neurological symptoms.
- Record previous ACS/PCI/CABG, bleeding, stroke, ulcer, anticoagulants, erectile-dysfunction medicines and allergies.
- Ask about aspirin already taken, time of onset and contraindications to antiplatelet/nitrate therapy.
- Assess pregnancy possibility, renal disease and risk of aortic dissection or pulmonary embolism.
6. ABCDE and immediate actions
| Step | Assess | Action |
|---|---|---|
| A – Airway | Patency, speech, consciousness and aspiration risk. | Open/protect airway, suction and prepare support if pulmonary oedema or arrest. |
| B – Breathing | RR, SpO₂, effort, crackles, wheeze and pulmonary oedema. | Oxygen only when hypoxaemic/distressed, upright position and ventilatory support if failing. |
| C – Circulation | Pulse, BP, perfusion, ECG rhythm and shock. | 12-lead ECG rapidly, cardiac monitor, IV access, aspirin if safe and urgent transport. |
| D – Disability | AVPU/GCS, glucose, syncope and stroke signs. | Check glucose, protect airway and assess cardiogenic hypoperfusion. |
| E – Exposure | Skin, sweating, oedema, medication patches and trauma. | Keep warm, identify dissection/PE clues and preserve dignity. |
7. ECG and diagnosis
- Obtain a 12-lead ECG as early as possible—often within 10 minutes of arrival—and repeat it when pain persists, recurs or the first ECG is nondiagnostic.
- Look for ST elevation/depression, T-wave inversion, new bundle-branch patterns, posterior/inferior changes and dysrhythmia.
- Do not wait for troponin to activate a STEMI reperfusion pathway when the ECG and clinical picture are diagnostic.
- Serial high-sensitivity troponin, FBC, electrolytes, renal function, glucose, coagulation and chest imaging are guided by the clinician.
- Consider aortic dissection, PE, pneumothorax, pericarditis, oesophageal rupture, pneumonia and reflux in the differential.
8. Initial medicines and precautions
- Aspirin: give the protocol loading dose promptly if ACS is suspected and there is no true allergy, active major bleeding or other contraindication; do not delay ECG/transfer.
- Nitrates: may relieve ischaemic pain when BP is adequate; avoid in hypotension, suspected right-ventricular infarction, severe aortic stenosis or recent PDE-5 inhibitor use.
- Oxygen: not routine for normal saturation; give for hypoxaemia, respiratory distress or shock.
- Analgesia: use prescribed, carefully monitored analgesia; severe pain and anxiety increase sympathetic demand.
- Anticoagulants/P2Y12 inhibitors/statins: selected by the senior clinician/cardiology pathway after bleeding, renal and reperfusion assessment.
- Record medicine, dose, time, contraindication check and response.
9. Reperfusion and hospital management
- Activate the nearest PCI/cardiology pathway for STEMI or high-risk ACS and pre-alert the receiving facility.
- Primary PCI is preferred when timely available; approved fibrinolysis may be considered when PCI delay exceeds the local threshold and no contraindication exists.
- For NSTEMI/unstable angina, use risk stratification, serial ECG/troponin, antithrombotic treatment and invasive assessment according to current guideline.
- Search for and treat precipitating anaemia, infection, hypoxia, arrhythmia, severe hypertension or stimulant exposure.
- Transfer with continuous ECG/SpO₂ monitoring, IV access, defibrillator availability and a clear time-stamped handover.
10. Complications and emergency responses
| Complication | Clues | Immediate direction |
|---|---|---|
| Ventricular dysrhythmia | Palpitations, collapse, irregular pulse or pulselessness. | Monitor, defibrillate/CPR for arrest and correct hypoxia/electrolytes. |
| Cardiogenic shock | Hypotension, cold mottled skin, confusion, oliguria. | Urgent cardiology/critical care; cautious fluids and vasoactive support by experts. |
| Acute pulmonary oedema | Severe dyspnoea, crackles, pink froth, hypoxaemia. | Upright, oxygen/CPAP as indicated, nitrates only if BP permits and urgent escalation. |
| Bradyarrhythmia/heart block | Syncope, slow pulse, inferior infarct pattern. | Monitor, atropine/pacing pathway and cardiology support. |
| Mechanical complication | New murmur, acute failure, persistent shock or tamponade signs. | Urgent echocardiography and specialist intervention. |
11. Nursing and EMT care plan
| Problem | Interventions | Evaluate |
|---|---|---|
| Myocardial ischaemia/pain | Rest, ECG monitoring, prescribed medicines, reduce exertion and reassess pain. | Pain, ECG changes, BP and rhythm. |
| Reduced cardiac output | Frequent vitals, urine, mental state, perfusion and fluid balance. | BP, refill, skin, urine, lactate and consciousness. |
| Respiratory compromise | Upright position, oxygen when indicated, pulmonary-oedema precautions and airway readiness. | SpO₂, RR, crackles, work of breathing and gas exchange. |
| Bleeding risk | Check puncture sites, stool/urine, bruising, haemoglobin and medication reconciliation. | No major bleeding; timely escalation. |
| Anxiety/education | Explain ECG/reperfusion, involve family appropriately and teach risk-factor control. | Understanding and adherence to follow-up. |
12. Special populations
- Women and older adults: fatigue, dyspnoea, nausea, jaw/back pain or confusion may replace classic chest pain.
- Diabetes: autonomic neuropathy may produce silent or atypical infarction; maintain a low threshold for ECG.
- Pregnancy: involve obstetric/cardiology specialists; balance antithrombotic and imaging decisions with maternal urgency.
- Renal disease: adjust medicines and contrast decisions; monitor potassium and fluid status.
- Bleeding/anticoagulation: document history and avoid unapproved antithrombotic duplication.
13. Discharge and secondary prevention
- Confirm the diagnosis, medication plan, follow-up and rehabilitation referral before discharge.
- Teach adherence to prescribed antiplatelet, statin, beta-blocker/ACE-inhibitor and other therapy; never stop dual antiplatelet therapy without cardiology advice.
- Stop smoking, control BP/diabetes/lipids, improve diet, resume activity through cardiac rehabilitation and recognise recurrent symptoms.
- Explain when to call emergency services: chest pressure, severe dyspnoea, syncope, palpitations or new weakness.
14. Clinical scenarios
Scenario 1 – STEMI. A 58-year-old has crushing chest pressure, sweating and ST elevation on ECG. Give aspirin if safe, monitor, activate the reperfusion pathway, pre-alert PCI/fibrinolysis-capable care and avoid delaying transfer for nonessential tests.
Scenario 2 – atypical diabetic ACS. A diabetic patient has sudden breathlessness, nausea and weakness without pain. Obtain an ECG promptly, check glucose and treat as possible ACS until excluded.
Scenario 3 – ACS with pulmonary oedema. A patient has chest pressure, BP 190/110, crackles and pink froth. Sit upright, oxygen/positive-pressure support as indicated, urgent cardiology review and nitrates only if appropriate.
Scenario 4 – shock after infarction. A patient is cold, confused and hypotensive after chest pain. Monitor, obtain IV access, avoid indiscriminate fluids and urgently escalate for cardiogenic shock/revascularisation care.
15. Common errors to avoid
- Assuming a normal first ECG excludes ACS; repeat when symptoms continue.
- Giving oxygen routinely to every patient or withholding it from hypoxaemia/shock.
- Giving nitrates in hypotension, right-ventricular infarction or recent PDE-5 inhibitor use.
- Delaying STEMI reperfusion for troponin or nonessential imaging.
- Missing atypical ACS in women, older adults and people with diabetes.
- Stopping antiplatelet therapy or failing to assess bleeding risk.
ACS emergency check – “ECG FAST”
E – Evaluate ABCDE and pain
C – Cardiac monitor and 12-lead ECG
G – Give aspirin if safe and guideline-approved
F – Find STEMI/shock/pulmonary oedema
A – Activate reperfusion/cardiology pathway
S – Serial ECG, troponin and observations
T – Transfer with time-stamped handover
E – Evaluate ABCDE and pain
C – Cardiac monitor and 12-lead ECG
G – Give aspirin if safe and guideline-approved
F – Find STEMI/shock/pulmonary oedema
A – Activate reperfusion/cardiology pathway
S – Serial ECG, troponin and observations
T – Transfer with time-stamped handover
16. Revision questions
- Differentiate unstable angina, NSTEMI and STEMI.
- List six atypical ACS symptoms.
- Why is early 12-lead ECG important?
- When should aspirin, oxygen and nitrates be avoided?
- Describe the first five minutes of suspected STEMI management.
- List five complications and their emergency responses.
17. Key take-home points
- ACS requires immediate assessment, ECG and monitored referral.
- Symptoms may be atypical or painless, especially in diabetes, women and older adults.
- Aspirin is commonly first-line when safe; oxygen is targeted to hypoxaemia, not given automatically.
- STEMI requires immediate reperfusion activation; do not wait for troponin.
- Recognise dysrhythmia, pulmonary oedema and cardiogenic shock early.
Safety note: This is educational content for EMT students. Aspirin, nitrates, anticoagulants, thrombolysis, oxygen targets and reperfusion decisions must follow current Uganda protocols, contraindication checks and senior/cardiology supervision.