Undifferentiated chest pain is a presenting complaint facing the emergency medicine clinician with ever increasing frequency.1 Increasing public awareness regarding ischaemic heart disease has helped contribute towards understandable increasing concern. The net result is that patients hold a lower threshold to present to the emergency department (ED) for assessment.

With these patients holding a lower pretest probability for acute coronary syndrome, the art of emergency medicine is being able to risk-stratify patients into those requiring admission for further assessment for a possible acute coronary syndrome and discharging home those patients whose likelihood of the disease is under the test threshold. Setting your threshold too high for investigation leads to unacceptable low pick up of cases and a missed opportunity to treat a disease with a significant morbidity and mortality; set your threshold too low for investigation and not only do you exposure patients to the elevated risk of false positives and unnecessary and potentially harmful treatment but you also increase the burden of over investigation upon an acute healthcare system already bursting at the seams.

It is well documented that clinicians are not able to accurately estimate the pretest probability for acute coronary syndrome accurately, with …