I. Initial Approach to the patient with Chest painChest pain is one of the most feared symptoms in primary care. While the priority in any patient who presents with chest pain is to exclude catastrophic or life threatening (cardiac) causes, non-life-threatening etiologies, which may be functionally disabling, are much more common in the primary care setting and require a cost-effective approach to diagnosis. The correct diagnosis is most often derived from a detailed history that is supported by specific physical findings, an electrocardiogram, and/or chest x-ray. Causes of chest pain in the outpatient clinic(See Table 1).The prevalence of chest pain etiologies varies according to the population studied. The presence of risk factors and the age of the patient population are important contributors to coronary artery disease (CAD) prevalence. (See Chapter on Overview of the Risk Factors for Cardiovascular Disease- DFH-IM-50). Emergency response to chest pain in the outpatient clinicChest pain due to myocardial infarction, pulmonary embolus, aortic dissection, or tension pneumothorax may result in sudden death. Any patient with a recent onset of chest pain, especially when the symptoms are ongoing, who may be potentially unstable based upon history, appearance, or vital signs, should be transported immediately to an emergency department preferably in an ambulance equipped with a defibrillator. Stabilization of such patients should begin in the prehospital setting and includes supplemental oxygen, intravenous access, and placement of a cardiac monitor. A 12-lead electrocardiogram should be obtained if possible. Patients who are thought to be experiencing a myocardial infarction should chew a 325 mg aspirin tablet. Sublingual nitroglycerin should be withheld if the patient has relatively low blood pressure without intravenous access or has recently taken sildenafil (Viagra). Evaluation of patients with chest pain The initial goal in the office evaluation of chest pain in stable individuals is to exclude CAD and other potentially life-threatening conditions. The history and physical examination, complemented by selected tests such as an electrocardiogram or chest radiograph, allow the physician to accurately diagnose most causes of chest pain, especially CAD, and to judge which patients likely have a benign etiology. The need for a good history and physical examination is emphasized by the fact that, the accuracy of the clinical examination for determining the presence of CAD is improved only marginally, if at all, by exercise testing. In a study which found that the predictive accuracy for CAD using clinical factors was 84 percent; inclusion of exercise test results increased the predictive accuracy to only 87 percent.