Cardiac arrhythmia affects more than 700 000 people in England, and is consistently in the top ten reasons for admission, placing a significant strain on emergency department time and bed availability (DH, 2005). Following the introduction of pre-hospital thrombolysis as part of the National Service Framework (NSF) for Coronary Heart Disease (CHD), the acquisition and interpretation of 12 lead ECGs has become a routine part of UK paramedic practice. Although training models have varied nationally, the main focus has been on the use of 12 lead ECGs to identify changes associated with ST elevation myocardial infarction (STEMI) in order to facilitate early reperfusion measures.