What are the red flags for acute chest pain?

Life-Threatening Diagnoses Not to Miss

The primary focus in acute chest pain should be exclusion of these potentially fatal conditions:

1. Acute coronary syndrome (AMI, unstable angina): by far the most common life-threatening cause
2. Pulmonary embolism
3. Aortic dissection
4. Spontaneous pneumothorax
5. Oesophageal rupture

Clinical Red Flags (NSW ACI ECAT Protocol)

Historical

• Known cardiac history
• Multiple cardiac risk factors (age >55, family history, hypertension, hyperlipidaemia, diabetes, smoking, Aboriginal and Torres Strait Islander peoples)

Clinical

• Altered level of consciousness
• Syncope
• Shortness of breath
• Active or ongoing chest pain / ischaemic symptoms
• Ischaemic ECG changes
• Arrhythmia
• Hypotension
• Diaphoresis

Associated Symptoms Suggesting Cardiac Origin

• Pain radiating to jaw, shoulder, arm, or epigastrium
• Palpitations
• Nausea/vomiting
• Pallor
• Lethargy/fatigue

Criteria for Immediate ED Referral (Victorian DoH)

Direct to ED via ambulance if suspected ACS with any of the following:

• Severe or ongoing chest pain
• Chest pain lasting ≥10 minutes
• Chest pain at rest or with minimal activity
• Severe dyspnoea
• Syncope or pre-syncope
• RR >30 breaths/min
• HR >120 bpm
• SBP <90 mmHg
• Heart failure or suspected pulmonary oedema
• ST elevation or depression on ECG
• Complete heart block or new LBBB

Also refer immediately for suspected PE or aortic dissection.

High-Risk Features for ACS (NHF/CSANZ 2025)

The 2025 Australian ACS Guideline identifies these high-risk features requiring inpatient evaluation:

• Haemodynamic instability or cardiogenic shock
• Recurrent or ongoing pain refractory to treatment
• Cardiac arrest
• Recurrent dynamic ST-T wave changes
• Sustained ventricular tachycardia or high-degree AV block
• Mechanical complications (e.g. new systolic murmur)
• Acute heart failure

Atypical Presentations

Women, older adults, and people with diabetes may present without classic chest pain. Associated symptoms can include jaw, neck, shoulder or back pain, fatigue, nausea, vomiting, dizziness, indigestion, and breathlessness. Women are more likely to be misdiagnosed with non-cardiac pain and experience delays in receiving life-saving procedures.

GP-Specific Considerations

In primary care, patients with suspected ACS (including new-onset angina) should be referred urgently to the nearest ED. Those with STEMI or ongoing chest pain, dyspnoea, syncope/pre-syncope, or palpitations should be transferred as an emergency via ambulance. An ECG should be recorded within 10 minutes of first clinical contact.