Introduction
Chest pain is a common symptom prompting people to present
at an emergency department (ED), estimated to constitute
700,000 cases annually in England and Wales.1 A study
conducted in the UK found that of those visiting an ED
with chest pain, 11% had electrocardiogram (ECG) markers
of acute coronary syndrome (ACS) and 34.5% had diagnosed
ACS.2 Patients with symptoms indicative of ACS
pose a challenge to practitioners. Immediate assessment of
their clinical condition and ECG findings is essential.3
Those with persistent symptoms and ST-segment elevation
(STEMI) on the ECG have a well-defined pathway for
achieving rapid opening and reperfusion of the infarctrelated
artery by primary percutaneous coronary intervention
(PCI) or thrombolytic therapy. Patients without
ST-elevation on the ECG are more difficult. Their ECG
may have no ischaemic changes or they may have persistent
or transient ST-segment depression, T-wave inversion
or flat or pseudo-normalised T-waves.3 These individuals
should be further assessed in terms of history, physical
examination and biomarkers (chiefly troponin).