REASONING GP · Clinical algorithm · Quick reference

Acute chest pain in adults — triage and diagnostic approach

Daytime GP and OOH/111 face-to-face or remote. Screen for the killers, give the pre-transfer treatment that is allowed, then classify. Ongoing management of each diagnosis is in the full Steps pathway.
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AdultsGP + OOHDiagnosis firstv1.0 · Sep 2026
Core rule. Chest pain present now, or in the last 12 hours, is an acute coronary syndrome until an ECG and troponin in hospital say otherwise (CG95). Response to GTN, chest-wall tenderness, a normal ECG, young age or an anxious patient does not exclude a serious cause. With no 12-lead ECG, no oximeter or no safe transport, the destination is the acute-care route, not a longer history.
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Before any history: is this an emergency now? Stop the consultation and call 999 if any of these is present
Collapse or airway/breathing/circulation compromise · GCS <15 or falling · systolic BP <90, pulse >120 or <40, new SpO₂ <94%, RR ≥30 · cardiac-sounding pain now, or within 12 hours with an abnormal or unavailable ECG (CG95) · sudden tearing pain with pulse deficit, arm-to-arm BP difference or new neurology · acute breathlessness with a silent hemithorax or tracheal deviation. ABCDE, observations, exact onset time, hand over. Do not delay transfer for an ECG, aspirin, bloods, a CXR or a fuller history.
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Define the pain in four lines Enough to place the patient in the table below; the full history can wait

Time

Present now? Exact onset. Hours since last pain: under 12 · 12–72 · over 72 (CG95 sets urgency by this). Sudden or gradual. At rest, on exertion, on breathing, lying flat.

Character

Constricting or heavy in chest, neck, jaw or arms, on exertion, relieved by rest or GTN within about 5 minutes (CG95) · tearing to the back · sharp pleuritic · burning retrosternal · reproducible on pressing.

Context

Age, diabetes, smoking, hypertension, family history, known coronary disease · immobility, surgery, cancer, pregnancy/postpartum, oestrogen · cocaine · anticoagulants · Marfan, known aneurysm · immunosuppression.

Associated

Breathlessness, sweating, nausea, syncope, palpitations · haemoptysis, leg swelling · fever, cough, sputum · dysphagia, reflux, haematemesis, melaena · dermatomal rash.
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Red-flag screen: trigger → concern → destination → what to do before handover One row is enough; do not add up reassuring features
Trigger / red flagLeading concern · destinationDo now · do not delay
Cardiac-sounding pain now or within 12 hours: central heaviness or tightness, radiation to arm, jaw or back, with sweating, nausea or breathlessness; any chest pain with an abnormal ECG or instability; chest pain after cocaine within 48 hours. Pain-free, normal ECG, pain 12–72 hours ago is same-day (CG95). Acute coronary syndrome
999 now Same-day acute assessment if 12–72 h, pain-free, ECG normal		 Record exact onset and whether pain is ongoing. Aspirin 300 mg orally as soon as possible unless allergic; write dose and time on the handover (CG95). ECG only if it will not delay transfer; a normal ECG does not exclude ACS. Response to GTN does not make or exclude the diagnosis. No oxygen unless SpO₂ <94%. Diabetes, age over 75 and women present atypically: breathlessness or epigastric pain alone can be the ACS.
Sudden severe tearing or ripping pain, maximal at onset, radiating to the back or migrating; syncope; pulse deficit or arm-to-arm BP difference; new neurology; Marfan, known aneurysm or aortic surgery; pregnancy. Acute aortic dissection
999 now		 Record both-arm BP, pulses and "suspected aortic dissection" on the handover, so antiplatelet decisions are made in hospital. Do not delay for an ECG: ischaemic changes occur when dissection involves a coronary artery. Do not lower BP with oral drugs.
Pleuritic pain with breathlessness, pulse >100, SpO₂ <94%, haemoptysis, unilateral leg swelling, syncope; recent immobility, surgery, cancer, pregnancy or postpartum, combined hormonal contraception or HRT. Pulmonary embolism / pneumothorax
Same-day acute assessment 999 if hypoxic, hypotensive or syncope		 Observations including RR and SpO₂; two-level PE Wells (NG158). Wells more than 4: immediate CTPA via the acute route, not a D-dimer from primary care. Wells 4 or less: D-dimer only if same-day; interim anticoagulation if delayed. Pregnancy or up to 6 weeks postpartum: no D-dimer, no Wells; direct maternity or acute assessment (RCOG). Tracheal deviation with hypotension = tension pneumothorax → 999.
Haemodynamic or rhythm compromise: breathless at rest, orthopnoea, new oedema or crackles, pulse >120 or <40, syncope, raised JVP, muffled heart sounds, new murmur, BP ≥180/120 with chest pain. Acute heart failure / arrhythmia / tamponade / hypertensive emergency
999 now		 ECG if available without delay; observations. Do not give a diuretic and review. Do not treat BP ≥180/120 with chest pain using oral drugs (NG136): transfer. Do not attribute tachycardia or hypoxia to anxiety.
Fever, cough, purulent sputum, focal chest signs, rigors, confusion; CRB65 — confusion, RR ≥30, systolic BP <90 or diastolic ≤60, age ≥65 (CG191): score ≥3, or 1–2 with hypoxia or frailty, needs hospital. Pneumonia / empyema / sepsis
Same-day acute assessment 999 if sepsis or shock		 Observations including temperature and SpO₂; record CRB65. SpO₂ <94% or NEWS2 ≥5 is an acute-care decision, not oral antibiotic-and-review. Immunosuppressed or asplenic: lower the threshold; neutropenic sepsis is 999.
Epigastric or lower chest pain with rigidity, haematemesis or melaena, pain after forceful vomiting, or severe pain on NSAIDs or anticoagulants. Perforation / upper GI bleed / oesophageal rupture / pancreatitis
Same-day surgical assessment 999 if shock or haematemesis		 Observations, abdominal examination, drug history. Do not give a PPI and review. New epigastric pain with sweating or breathlessness is inferior MI until the ECG says otherwise.
Pregnancy, up to 6 weeks postpartum, or cancer / anticoagulated / immunosuppressed with any new chest pain. PE · spontaneous coronary artery dissection · aortic dissection · pre-eclampsia · neutropenic sepsis
Same-day maternity / acute assessment 999 if unstable		 Record gestation or postpartum interval, BP, SpO₂ and cancer treatment; speak directly to the maternity or acute unit. No D-dimer in pregnancy. A young woman with no risk factors can have ACS: record the ECG decision, not an assumption.
Age 40 and over with unexplained chest pain plus one other unexplained symptom (cough, fatigue, breathlessness, weight loss, appetite loss), or chest pain alone if ever smoked or asbestos-exposed. Lung cancer / mesothelioma
Urgent CXR within 2 weeks · NICE NG12		 Direct-access urgent CXR (NG12). A normal CXR with persisting symptoms still needs a decision on urgent suspected-cancer referral. Do not attribute new chest pain in a smoker aged 40 and over to musculoskeletal strain without a CXR.
Safety rule. Relief with GTN, antacid, analgesia or rest proves nothing (CG95). Chest-wall tenderness, a normal ECG, normal SpO₂ and young age each lower probability; none excludes ACS, PE or dissection when the history fits. If a row applies and the safe destination is unavailable, escalate rather than observe.
Colour is semantic: red = emergency now · amber = same-day acute assessment · blue = define/assess · green = benign diagnosis established · purple = uncertain / specialist route (including 2WW). Continued on page 2: classification, phenotype classifier, routine referral, primary-care treatment, endpoint.
REASONING GP · Acute chest pain in adults — triage and diagnostic approach
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Focused examination and investigation Only after the emergency question is answered; remote assessment that cannot deliver these is an escalation criterion

Observations

BP both arms, pulse rate and rhythm, RR, SpO₂, temperature, GCS; NEWS2 if available. Tachycardia or SpO₂ <94% is never explained by anxiety here.

System examination

JVP; heart sounds, murmur, rub; lung bases, unilateral reduced breath sounds or hyper-resonance, tracheal position; peripheral pulses; calves; epigastrium; skin for zoster.

Targeted signs

Chest-wall tenderness reproducing the pain (supports musculoskeletal; does not exclude ACS) · worse lying flat, eased sitting forward · Marfan habitus · pulse deficit or BP difference · oedema · pain with swallowing or meals.

Investigations

12-lead ECG if pain is present or recent and it does not delay transfer; normal does not exclude. Troponin is a hospital test unless pain was over 72 hours ago, ECG normal and a same-day result can be acted on (CG95). D-dimer only when Wells ≤4 and same-day (NG158). Urgent CXR per NG12. Not in primary care: exercise ECG for angina, GTN as a diagnostic trial, CT coronary angiography.
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Classify: three exits, not two "Not cardiac" is not a diagnosis; name the alternative or name the uncertainty

Serious cause likely

Any red flag, abnormal observations or ECG, cardiac-character pain now or within 12 hours, or a high-risk context with a fitting history. Output: name the leading concern; use the destination in the table above; record treatment given and time.

Benign cause established

No red flags, normal observations, the whole pain explained by one phenotype below with supporting findings, cardiovascular risk considered. Output: record the phenotype, the supporting findings and the onward management pathway.

Unclassified / uncertain

Exertional or atypical pain now settled, first presentation with cardiovascular risk, mixed phenotype, no coherent pattern. Output: do not default to "musculoskeletal", "reflux" or "anxiety". State the uncertainty, exclusions outstanding, the section-6 routine route where one applies, and who reviews when.
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Chest-pain phenotype classifier (CG95, NICE CKS) Only once the red-flag screen is negative
Typical / atypical anginaThree features (typical) or two (atypical) of: constricting discomfort in the front of the chest, neck, shoulders, jaw or arms · precipitated by exertion · relieved by rest or GTN within about 5 minutes (CG95). Stable pattern, not at rest, not new in the last 12 hours. → Rapid access chest pain clinic; CT coronary angiography first-line. Do not use age, sex or risk factors to decide typicality.
Non-anginal chest painOne or none of the three features, normal ECG and observations: continuous or prolonged, unrelated to activity, brought on by breathing, or with dizziness, palpitations or dysphagia (CG95). With resting ECG changes it is referred like angina. Then find the phenotype below.
Musculoskeletal / costochondritisLocalised chest-wall pain reproduced by palpation or movement, often after exertion, coughing or lifting; no exertional pattern, normal observations and ECG. Tenderness supports but never excludes ACS or PE.
Gastro-oesophagealRetrosternal burning after meals or lying flat, with acid regurgitation, relieved by antacids; no exertional pattern (NICE CKS). Oesophageal spasm mimics angina and can respond to GTN: response does not classify (CG95). Dysphagia, weight loss, haematemesis or 55+ with resistant symptoms → NG12 upper GI pathway.
Panic / anxietyDiscrete episodes peaking within minutes with palpitations, breathlessness, tingling and fear; normal observations during and between episodes; no exertional trigger (DSM-5-TR). Only after cardiac and pulmonary causes are addressed.
Do not label by defaultPericarditis (pleuritic, worse lying flat, eased sitting forward, rub) is a same-day hospital diagnosis, not a GP NSAID prescription. Zoster before the rash: dermatomal burning and allodynia; review in 72 hours. Known angina with new rest pain is unstable angina → 999.
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Refer routinely from this consultation Not same-day, not 999 — the cases that leave by letter
Suspected stable angina — typical or atypical angina, or non-anginal pain with resting ECG changes → rapid access chest pain clinic (CG95) · known angina uncontrolled on two anti-anginals → cardiology (CG126) · reflux persisting after 8 weeks of PPI with no NG12 feature → gastroenterology (NICE CKS) · recurrent panic attacks → NHS Talking Therapies (NG113). Mark the letter "routine"; interim advice: stop and rest if pain on exertion, 999 if pain at rest or over 15 minutes. What remains below is what primary care treats today.
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The only treatment decisions that belong in this consultation What primary care treats today; everything else is in the management pathway
Suspected ACSAspirin 300 mg single loading dose orally as soon as possible unless clear evidence of allergy (CG95, NG185); give even if on regular low-dose aspirin. Write drug, dose and time on the handover. Pain relief is GTN and/or IV opioid by the ambulance team. If aortic dissection is the leading concern, withhold aspirin and say so on handover.
OxygenOnly if SpO₂ is below 94% and not at risk of hypercapnic respiratory failure, titrated to 94–98%; if at risk (COPD), 88–92% (CG95, BTS emergency oxygen). Not routine. Record SpO₂ before and after.
Known stable angina, single attack (pattern unchanged)GTN 400–800 micrograms sublingual spray (BNF): stop, sit, repeat after 5 minutes if pain persists; if pain persists 5 minutes after the second dose call 999 (CG126). Not within 24 hours of sildenafil or vardenafil, 48 hours of tadalafil. Not for undiagnosed chest pain: response to GTN does not classify (CG95). Rest pain or pain at lower workload is unstable angina → 999.
Dissection, PE, tension pneumothorax, tamponade, arrhythmia, acute heart failure, perforation, hypertensive emergencyTransfer is the treatment. Do not lower BP with oral drugs; no diuretic and review; no anticoagulant when dissection is possible; no oral antibiotics when CRB65 is 3 or more; no CXR, D-dimer or troponin that delays conveyance. Analgesia is permitted if it does not delay transfer.
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Endpoint and documentation Finish with one of four conclusions and a named owner

1 · Time-critical serious

999 route taken; suspected diagnosis, exact onset, observations, ECG if done, aspirin dose and time, both-arm BP if dissection suspected.

2 · Serious possible

Same-day acute, surgical or maternity assessment arranged; the question being excluded, Wells or CRB65 score, who was spoken to, deadline to be seen.

3 · Benign established

Phenotype and supporting findings; observations and ECG result; cardiovascular risk acknowledged; management pathway; safety-net understood.

4 · Unclassified

Uncertainty stated; chest pain clinic or urgent CXR referral sent, with date; interim advice on exertion and driving; review owner and timeframe; escalation criteria.
Why a benign diagnosis is safe today, in one line: no row on the page-1 screen applies · observations normal including SpO₂ and pulse · ECG normal if pain was present or recent · the whole pain explained by one phenotype · cardiovascular and VTE risk recorded · written safety-net and an agreed review. Safety-net wording: call 999, do not drive, if chest pain lasts more than 15 minutes, comes on at rest, or comes with breathlessness, sweating, nausea, collapse or pain spreading to the arm, jaw or back; same-day contact for pain on less exertion than before, new breathlessness, coughing blood, a swollen painful leg, or black stools.
OOH / remote limitation. Convert to face-to-face or emergency assessment if pain is present during the call; time since the last pain is unclear; BP, pulse, SpO₂ or a 12-lead ECG cannot be obtained; the pain is exertional or cardiac in character with risk factors; the patient is pregnant, immunosuppressed or anticoagulated; or safe transport cannot be guaranteed — the patient must never drive themselves. Under time pressure the default is the safer destination.
Clinical decision support only; follow local emergency-transfer, emergency-medicines and referral policies and check doses against the current BNF. Source hierarchy: NICE guidelines and CKS first, then BNF/MHRA for doses and safety, then national specialty guidance. Sources: NICE CG95 Chest pain of recent onset · NG185 Acute coronary syndromes · CG126 Stable angina management · NG158 Venous thromboembolic diseases · CG191 Pneumonia in adults · NG51 Sepsis · CG187 Acute heart failure · NG136 Hypertension in adults · NG12 Suspected cancer · NG113 Generalised anxiety and panic disorder · NICE CKS Chest pain, Angina, Dyspepsia · BNF · MHRA · BTS Pleural disease guideline 2023 · BTS Emergency oxygen guideline · RCOG Green-top 37b · RCEM Aortic dissection best practice guideline · DSM-5-TR. Review after any guidance or medicines-safety update, otherwise every 6 months. © Reasoning GP · gpreasoning.uk