Chest pain in the emergency department: role of cardiac imaging

Millions of patients with acute chest pain, or other symptoms suggestive of acute coronary syndrome (ACS), are evaluated daily in emergency departments (EDs) around the world.

These patients comprise a broad spectrum of cardiac risk. At one end of the spectrum are patients with abnormal ECG and thus definite ACS who require immediate invasive diagnostic procedures and possibly coronary intervention. At the other end of the spectrum are patients with atypical and non-cardiac chest discomfort and normal ECG who can be sent home safely. In between these two extremes are numerous patients with atypical presentation of ischaemic chest pain and normal or non-diagnostic ECG who might have ACS. Cardiac imaging may play an important role in triaging and directing clinical management of these patients.

Until the institution of ED based chest pain centres (CPCs) in the USA, about two thirds of these patients with acute chest pain and normal or non-diagnostic ECG usually were admitted to the hospital for further evaluation, whereas the remaining one third of the patients was sent home. Of those admitted, as much as one half of patients are labelled with the vague admission diagnosis of “chest pain” or “rule-out-infarction” (fig 1). In the latter group of patients, complete diagnostic work-up typically confirms a cardiac cause for the symptoms in only about 10%. Thus, about 90% of these hospitalisations were in retrospect unnecessary.1 On the other hand, some studies have indicated that of the patients sent home, about 2–4% had unrecognised acute myocardial infarctions (MIs). Missed MI is a major cause for legal action against ED physicians in the USA.