Worldwide, ischemic heart disease remains the leading cause of death [1]. In the majority of developed countries, cardiovascular disease is the major cause of death, disability, lost productivity and reduced quality of life in adults [2]. In the US, acute myocardial infarction has remained the leading cause of death since the beginning of the century, presently resulting in more than 500 000 deaths annually [3]. Acute myocardial infarctions also result in consequential morbidity in the form of additional complications, such as congestive heart failure, cardiogenic shock and dysrhythmias. Unstable angina presents as frequently as acute myocardial infarctions, has a high risk of progression to myocardial infarction or death, and has a comparable impact on healthcare resources. However, unstable angina also offers the opportunity to intercede and minimize or even avoid progression to myocardial infarction.
Despite significant advances in the diagnosis and management of heart disease, which have produced dramatic improvements in the patient's prognosis, the mortality and morbidity associated with myocardial infarctions remain high. Key to the success of current treatments is early intervention and rapid initiation of therapy. The earlier one can detect the development of a potential cardiac event, the greater the likelihood that one can intervene successfully, reducing or avoiding the crisis event. Once a cardiac event occurs, shortening the interval between onset of symptoms and initiation of treatment correlates directly with smaller infarct size, reduced complications, and ultimately higher survival. Mortality for patients receiving treatment within 70 min of the cardiac event is 1.6%, as compared with 6% for patients treated within 6 h [4].
Unfortunately, medical intervention in acute coronary syndromes is frequently ineffective because treatment, for various reasons, is delayed. The first barrier to effective treatment can occur when a patient waits too long after symptom onset to present to the emergency department - whether from ignorance of the symptomatology or reluctance to admit a cardiac origin. The median time from onset of chest pain to arrival at the emergency department exceeds 2 h [5]. The second barrier can be found in a busy emergency department; if the patient is not in obvious distress, a significant amount of time may elapse between the patient's arrival at the emergency department and initiation of treatment [6]. Finally, patients may not receive timely treatment when they are mistakenly sent home. Approximately 5% of patients with myocardial infarctions (in the US, this is more than 35 000 annually) are incorrectly diagnosed and mistakenly discharged from the hospital - only to be later admitted with severe and possibly fatal infarctions [7-10].
Therefore, achieving optimal clinical outcomes requires informed patients recognizing cardiac symptoms and seeking treatment immediately and physicians rapidly and accurately diagnosing and treating the patients. Chest pain centers were developed specifically to overcome the previously mentioned barriers and provide better care [11, 12].
Working within the emergency department, chest pain centers provide highly trained specialists to evaluate and treat patients who present with chest pain, distinguishing them from the emergency departments, which have a more trauma-oriented focus. Chest pain centers seek to reduce the mortality and morbidity currently associated with myocardial infarctions by improving patient response to chest pain, improving diagnosis and reducing the 'door-to-needle time,' promoting earlier intervention for patients with prodromal symptoms, and reducing or eliminating the release of patients at risk [11-13]. Chest pain centers often provide programs to educate the community to identify early heart attack symptoms (prodromal symptoms) and encourage them to present promptly for evaluation at the clinic - rather than waiting until the pain is severe and life threatening. As patients and physicians recognize the importance of anginal pain as a prodromal symptom of infarction, the treatment paradigm may be shifted from damage control using thrombolytic therapy to preventive intervention - the use of antithrombotic and antiplatelet agents, possibly including the new glycoprotein GP Ilb/Illa receptor antagonists. Additionally, cardiac care at chest pain clinics is enhanced by a willingness to treat and manage patients with ischemic disease who do not present with an acute myocardial infarction [11-13]. This represents the majority of chest pain patients, since only 10-15% of those presenting to the emergency department are diagnosed as having a myocardial infarction [14-16]. A patient who presents with chest pain and is curtly dismissed from a busy emergency department will be unwilling to risk such embarrassment the next time chest pain develops. Ironically, by providing earlier and improved care for chest pain patients, the clinics are also proving to be very cost-effective - patients who previously would have been admitted to rule out the possibility of myocardial infarction (ROMI) are now evaluated and often released for later follow-up by the clinic.
