Time-critical presentations
Chest pain — emergency assessment
Overview and approach
ACS is time-critical myocardial ischaemia and includes infarction and unstable angina; use the current Australian ACS pathway.
Assessment and clinical features
ABCDE, pain/equivalent symptoms, onset, haemodynamics and bleeding/dissection clues; obtain prompt ECG and repeat if symptoms continue.
Differentials and investigations
Serial high-sensitivity troponin with assay-specific timing, ECG and selected echo/imaging; recognise posterior/right-ventricular or other occlusion patterns.
Management and follow-up
Activate urgent cardiology/reperfusion pathways when indicated; antithrombotics and anti-ischaemic treatment require contraindication checks and local guidance.
- Your scenario (65-year-old man, anterior STEMI, cath lab delayed, then VT with a pulse, VF, VT and PEA arrests, then ROSC) is kept in the toggle below. Unstable tachycardia with a pulse needs synchronised cardioversion; pulseless VF/VT needs CPR and defibrillation; PEA needs CPR and adrenaline without defibrillation. See the Cardiac arrest, Arrhythmias and Acute MI pages.
- Post-ROSC (ANZCOR 11.7) (1): oxygen 100% until reliable SpO2 then 94 to 98%; PaCO2 normal; MAP at least 60 to 65 mmHg or SBP above 100 mmHg; prevent fever (37.5 °C or below) in comatose patients; ST elevation needs early angiography.
Red flags and clinical pearls
Normal initial ECG or troponin does not exclude ACS. Routine oxygen is not indicated without hypoxaemia; aortic dissection can mimic infarction.
Notes and images (STEMI arrest scenario)
Scenario summary
A 65-year old man presents to the ED via EMS with chest pain. He is initially mildly hypotensive and tachycardic. An ECG will show an anterior STEMI. The team will need to activate the cath lab, which will be delayed by 20 minutes. The patient will go into VT with a pulse, and the team will need to provide synchronized cardioversion. The patient will then go into VFib arrest followed by VT arrest, and the team will need to perform CPR and defibrillate for both scenarios. The patient will subsequently go into a PEA rhythm, at which time the team should continue to give CPR, epinephrine and not defibrillate. Lastly, the patient will have ROSC and the team will need to provide post-ROSC care. The case ends with the cath lab calling to say they are ready for the patient.
Case
A 65-year-old male presents to the ED from a local fitness centre via EMS with chest pain. He was given 325 mg ASA PO in the ambulance. He arrives alert and oriented, distressed and clutching his chest.
Baseline management
A: patent airways, clear
B: breathing normal, RR, auscultation
C: cap refill, vitals, IV access, bloods (CRP, CK, ESR, FBC, UEC, LFT, cap glucose), bolus given, ECG, CXR
D: no defib -activate cath lab
GCS
Progression 1 - VT with a pulse
sync cardioversion
- Cardioversion refers to the delivery of an electrical shock that is timed to the peak of the R wave on the EKG. This synchronization ensures that the electrical stimulation occurs only during the refractory period of the cardiac cycle minimizing the risk of iatrogenic arrhythmias
- Synchronized cardioversion is a procedure similar to electrical defibrillation in that a transthoracic electrical current is applied to the anterior chest to terminate a life-threatening or unstable tachycardic arrhythmia.
- Sync cardioversion is different to defib due to the less energy given and the different time in cycle that it is given
- Rhythms that require sync cardioversions
- Unstable Atrial fibrillation (AF)
- Atrial flutter (types I and II)
- Atrial tachycardia.
- Ventricular tachycardia with a pulse.
- Supraventricular tachycardia.
Progression 2 - V fib arrest
pulseless and unresponsive
30 CPR - 2 breaths
Defib
Amiodarone 300mg IV
Notes
Last updated from Sen’s notes on 9 October 2026.