Diagnostic reasoning case · WHO Basic Emergency Care and HEARTS

Chest pain in an adult

Chest pain can come from the heart, the lungs, the aorta, the oesophagus or the chest wall. Without an ECG you rely on the character of the pain, the risk factors and a careful examination. When a heart attack is likely, the health centre does three things well: aspirin, a calm patient and a fast transfer.

  • Setting: Health centre with oxygen and a pulse oximeter but no ECG, 45 minutes from a hospital
  • For clinical officers, nurses and doctors at first-level facilities
  • Reviewed October 2026

The presentation

Ahmed, 58, runs a shop. An hour ago, while sitting at the counter, he felt a heavy pressure in the middle of his chest that spread to his left arm and jaw. He is sweating and feels sick. He has had high blood pressure for 6 years but takes his tablets only now and then. He smokes about 20 cigarettes a day.

Taken at triage.
Vital signValue
Pulse96 per minute, regular
Blood pressureRight arm 162/98, left arm 158/96 mmHg
Breathing rate22 per minute
SpO295% on air
Temperature36.6 °C
Conscious level (AVPU)Alert, sweaty, anxious

Tests at hand: Pulse oximetry (SpO2) · Blood glucose (finger-prick) · Haemoglobin (Hb)

Starting differential
  • Heart attack or unstable angina (acute coronary syndrome) Must not missStill possible
  • Aortic dissection Must not missStill possible
  • Pulmonary embolism Must not missStill possible
  • Tension pneumothorax Must not missStill possible
  • Pericarditis or pericardial effusion (including TB)Still possible
  • Pneumonia or pleurisyStill possible
  • Oesophageal reflux or ulcer painStill possible
  • Chest wall (musculoskeletal) painStill possible

Work through it

Read each question and decide your own answer first. Then open the model answer and see how the differential changes.

  1. Step 1 of 7 · Look

    ABCDE first. What do you check, and what does Ahmed need straight away?

    Model answer
    A
    Talking in full sentences; airway open.
    B
    Rate 22, SpO2 95%, equal breath sounds on both sides, no crackles.
    C
    Pulse 96 and regular, BP high in both arms, hands warm, capillary refill 2 seconds. No signs of shock.
    D
    Alert. Check glucose.
    E
    Sweaty. No injury.

    He is not in shock and is breathing adequately, but pain like this is an emergency. Sit him at rest, put in an IV cannula, and keep him under observation. Oxygen is not needed while SpO2 is normal: WHO no longer recommends it for every heart attack, only for those in shock or with difficulty in breathing.

    Recognise itPressure, tightness or crushing pain in the chest, with sweating, nausea or breathlessness, and pain moving to the jaw or arms, is a heart attack until shown otherwise.
    Differential now
    • Heart attack or unstable angina (acute coronary syndrome) Must not missLeading (moved up)
    • Aortic dissection Must not missStill possible
    • Pulmonary embolism Must not missStill possible
    • Pericarditis or pericardial effusion (including TB)Still possible
    • Pneumonia or pleurisyStill possible
    • Oesophageal reflux or ulcer painStill possible
    • Chest wall (musculoskeletal) painStill possible
    • Tension pneumothorax Must not missLess likely (moved down)
  2. Step 2 of 7 · Ask

    What do you ask to separate the causes, and which answer would stop you giving aspirin?

    Model answer
    • Character and onset: pressure or crushing (heart); sudden, tearing, going through to the back (aorta); sharp and worse on breathing (lung, pleura, pericardium); burning after food (oesophagus).
    • Radiation: jaw, arm or throat (heart); back or between the shoulder blades (aorta).
    • Previous chest pain on exertion that eased with rest (angina).
    • Breathlessness, coughing blood, a swollen painful leg, recent immobility, travel or surgery (pulmonary embolism).
    • Fever and cough (pneumonia); weight loss, night sweats or TB contact (TB pericarditis).
    • Relief when leaning forward (pericarditis); pain reproduced by pressing the chest wall, or after an injury (musculoskeletal).
    • Bleeding: vomiting blood, black stools, a known stomach ulcer, or a recent stroke.

    The pain is a constant heavy pressure, not tearing, and does not go through to his back. For 2 weeks he has had shorter tightness walking up the hill to his house, which eased when he stopped. No cough, no fever, no leg swelling, no recent travel. No vomiting of blood, no black stools, no ulcer history.

    Differential now
    • Heart attack or unstable angina (acute coronary syndrome) Must not missLeading
    • Pericarditis or pericardial effusion (including TB)Still possible
    • Aortic dissection Must not missLess likely (moved down)
    • Pulmonary embolism Must not missLess likely (moved down)
    • Tension pneumothorax Must not missLess likely
    • Pneumonia or pleurisyLess likely (moved down)
    • Oesophageal reflux or ulcer painLess likely (moved down)
    • Chest wall (musculoskeletal) painLess likely (moved down)
  3. Step 3 of 7 · Look

    What do you look for on the secondary examination, and why?

    Model answer
    • BP in both arms and both radial pulses: a large difference suggests aortic dissection.
    • Neck veins: raised in heart failure, tamponade and tension pneumothorax.
    • Heart sounds: a new murmur, a rub (pericarditis), muffled sounds (effusion).
    • Lungs: breath sounds on both sides (pneumothorax), crackles (heart failure or pneumonia), dullness (effusion).
    • Trachea: pushed to one side in tension pneumothorax.
    • Calves: one swollen and tender (clot).
    • Chest wall: tenderness that reproduces the pain exactly.
    • Neurology: new weakness (dissection can cause a stroke).

    BP is similar in both arms and both pulses are equal. Neck veins not raised. Heart sounds normal, no murmur or rub. Air entry equal, no crackles. Trachea central. Calves soft. Chest wall not tender. No weakness.

    Differential now
    • Heart attack or unstable angina (acute coronary syndrome) Must not missLeading
    • Pulmonary embolism Must not missLess likely
    • Pericarditis or pericardial effusion (including TB)Less likely (moved down)
    • Pneumonia or pleurisyLess likely
    • Oesophageal reflux or ulcer painLess likely
    • Aortic dissection Must not missSet aside for now (moved down)
    • Tension pneumothorax Must not missSet aside for now (moved down)
    • Chest wall (musculoskeletal) painSet aside for now (moved down)
  4. Step 4 of 7 · Test

    You have pulse oximetry, glucose and haemoglobin. What does each add?

    Model answer
    1. Pulse oximetry: SpO2 is the trigger for oxygen. Below 92% or with signs of distress, give oxygen; a low value also raises the chance of pulmonary embolism or heart failure.
    2. Glucose: diabetes is a major risk factor, and low glucose can mimic shock with sweating and confusion.
    3. Haemoglobin: severe anaemia can cause angina-like pain and changes how you give fluids.

    Results: SpO2 95% on air. Random glucose 9.4 mmol/L. Hb 14.6 g/dL.

    There is no ECG or troponin here, and you do not need them to act. The history and risk factors are enough to treat this as a probable heart attack.

    Differential now
    • Heart attack or unstable angina (acute coronary syndrome) Must not missLeading
    • Pericarditis or pericardial effusion (including TB)Less likely
    • Pneumonia or pleurisyLess likely
    • Oesophageal reflux or ulcer painLess likely
    • Aortic dissection Must not missSet aside for now
    • Pulmonary embolism Must not missSet aside for now (moved down)
    • Tension pneumothorax Must not missSet aside for now
    • Chest wall (musculoskeletal) painSet aside for now
  5. Step 5 of 7 · Do

    Do you give aspirin? What is the dose, and when must you not give it?

    Model answer

    Yes. For a suspected heart attack, WHO Basic Emergency Care gives aspirin 300 mg by mouth once, chewed or dispersed in water, as soon as possible.

    When not to give aspirinDo not give aspirin before an advanced provider has seen the patient if there is active bleeding, or if the pain was sudden, maximal at onset, sharp and tearing and goes through to the back (a possible tear in the aorta).

    Ahmed has neither. He chews 300 mg of aspirin at 14:20. Write the time down.

    • Pain relief per your national protocol; reassurance and rest.
    • Give oxygen only if SpO2 falls below 92%, or he becomes breathless or shocked.
    • IV line in place; give fluids only for signs of poor perfusion, and listen for crackles after each small amount.
    Differential now
    • Heart attack or unstable angina (acute coronary syndrome) Must not missLeading
    • Pericarditis or pericardial effusion (including TB)Less likely
    • Aortic dissection Must not missSet aside for now
    • Pulmonary embolism Must not missSet aside for now
    • Tension pneumothorax Must not missSet aside for now
    • Pneumonia or pleurisySet aside for now (moved down)
    • Oesophageal reflux or ulcer painSet aside for now (moved down)
    • Chest wall (musculoskeletal) painSet aside for now
  6. Step 6 of 7 · Do

    How do you arrange the transfer, and what do you hand over?

    Model answer

    He needs an ECG and treatment that may open the blocked artery, which is time-critical: this is an immediate referral.

    • Call ahead so the receiving team is ready.
    • He does not walk: carry him to the vehicle. A health worker goes with him.
    • On the way: pulse, BP, breathing, SpO2 and pain every 15 minutes. Watch for an irregular, very fast or very slow pulse, low BP or breathlessness.
    • Handover: time the pain started, character, BP in both arms, aspirin dose and time, other treatment, risk factors.

    Your pain is probably coming from your heart. The tablet you chewed helps the blood to flow. You need to be at the hospital now, where they can check your heart and treat it. Please stay lying back and do not walk.

  7. Step 7 of 7 · Ask

    When he comes back after the hospital, what is your part in preventing another heart attack?

    Model answer
    • Low-dose aspirin (75 to 100 mg daily) and a statin long term after a heart attack, as the hospital plan states.
    • Blood pressure control on the national HEARTS protocol, with a regimen he can take every day.
    • Help to stop smoking: the single most useful change.
    • Check for diabetes (his random glucose was 9.4 mmol/L): a fasting test at follow-up.
    • Teach him and his family what to do if the pain comes back: rest, and come straight in.

Must-not-miss conditions

ConditionCluesWhat to do at first-level care
Heart attack (acute coronary syndrome)Pressure or crushing central chest pain at rest, to jaw or arm; sweating, nausea, breathlessness; smoker, hypertension, diabetes, high cholesterol, family history.Aspirin 300 mg chewed (unless bleeding or tearing pain to the back); oxygen if SpO2 below 92% or shocked; IV line; immediate transfer.
Aortic dissectionSudden tearing pain radiating to the back or between the shoulder blades; unequal pulses or BP between arms; new stroke.No aspirin; keep calm and still; immediate transfer.
Pulmonary embolismSudden breathlessness, pleuritic pain, coughing blood, fast pulse, low SpO2; recent immobility, travel, surgery, pregnancy, cancer; a swollen leg.Oxygen; immediate transfer.
Tension pneumothoraxDifficulty breathing with low BP, absent breath sounds on one side, raised neck veins, trachea pushed away.Needle decompression, oxygen, IV fluids, then transfer.
Pericardial tamponadeSigns of poor perfusion, raised neck veins, muffled heart sounds; TB, cancer, kidney failure or trauma.IV fluids, rapid transfer for drainage.

Decision at first-level care

Ahmed has a probable acute coronary syndrome: an hour of crushing central chest pain at rest radiating to arm and jaw, with sweating, after two weeks of exertional angina, in a smoker with poorly controlled hypertension. Dissection, pulmonary embolism and pneumothorax are unlikely on examination. He is given aspirin 300 mg chewed and transferred immediately, accompanied.

Source: WHO and ICRC Basic emergency care (2018); IMAI district clinician manual, volume 1 (2011).

Treat here
  • Pain clearly reproduced by pressing the chest wall, after strain or minor injury, with normal vital signs and no risk factors: analgesia and advice.
  • Burning pain after food relieved by antacids, long history, normal examination: treat as reflux and review.
Observe and review
  • Brief pain that has fully settled, normal examination and vital signs, low risk: review the same day or next day, and come back at once if it recurs.
  • Exertional chest pain that eases with rest, now pain-free (stable angina): start treatment, refer routinely for assessment.
Refer (urgently, now)This patient
  • Chest pain at rest suggesting a heart attack: after aspirin, now.
  • Tearing pain to the back, or unequal pulses: now, without aspirin.
  • Chest pain with breathlessness, SpO2 below 92%, shock or an irregular pulse: now.
  • Pleuritic pain with fever and fast breathing, or with coughing blood: the same day or now if hypoxic.

Key learning points

  • ABCDE first, then the character, onset and radiation of the pain: they separate heart, aorta, lung and gut.
  • Without an ECG, typical pain with risk factors is enough to treat as a heart attack.
  • Aspirin 300 mg chewed for a suspected heart attack, except with active bleeding or tearing pain to the back.
  • Oxygen is for low SpO2, shock or difficulty in breathing, not for everyone with chest pain.
  • Measure BP in both arms: a large difference suggests aortic dissection.

Sources

  1. World Health Organization and International Committee of the Red Cross. Basic emergency care: approach to the acutely ill and injured. Participant workbook. 2018 (ISBN 9789241513081). Module 4 and medications: heart attack signs; aspirin 300 mg chewed or dispersed as a single dose; when not to give aspirin (active bleeding, tearing pain to the back); oxygen only for shock or difficulty in breathing; tension pneumothorax and tamponade signs and actions.
  2. World Health Organization. IMAI district clinician manual: hospital care for adolescents and adults, volume 1. 2011. Section 3.3, approach to chest pain: DDx table (stable angina, acute coronary syndrome, pneumonia, pulmonary embolus, reflux, musculoskeletal, oesophageal rupture, aortic dissection with asymmetrical pulses, tension pneumothorax, TB, pericarditis).
  3. World Health Organization, International Committee of the Red Cross and Médecins Sans Frontières. Interagency Integrated Triage Tool (age 12 and over). 2023. SpO2 below 92% as a high-risk vital sign.
  4. World Health Organization. HEARTS technical package for cardiovascular disease management in primary health care: evidence-based treatment protocols. 2018. Aspirin and statin after a heart attack; BP control; tobacco cessation (as summarised in the hypertension and CVD risk protocols).
Adapted from WHO guidance; not endorsed by WHO. This page paraphrases and adapts the WHO publications listed under Sources, which are licensed CC BY-NC-SA 3.0 IGO; the adapted text is shared under the same licence for non-commercial education. Reasoning GP is not affiliated with WHO or any other organisation named here. Use it alongside your national guidelines, essential medicines list and formulary, and your clinical judgement. Doses are given only where they come from a WHO source; otherwise follow your national guideline or formulary.