CHEST PAIN 2

Approach to the Patient

The evaluation of the patient with chest discomfort must accommodate two goals¾determining the diagnosis and assessing the safety of the immediate management plan. The latter issue is often dominant when the patient has acute chest discomfort, such as patients seen in the emergency department. In such settings, the clinician must focus on questions such as the safety of discharge to home, admission to a non-coronary care unit facility, or immediate exercise testing. displays a sequence of questions that can be used in the evaluation of the patient with chest discomfort, with the diagnostic entities that are most important for consideration at each stage of the evaluation.

Acute Chest Discomfort In patients with acute chest discomfort, the clinician must first assess the patient's respiratory and hemodynamic status. If either is compromised, initial management should focus on stabilizing the patient before the diagnostic evaluation is pursued. If, however, the patient does not require emergent interventions, then a focused history, physical examination, and laboratory evaluation should be performed to assess the patient's risk of life-threatening conditions, including acute ischemic heart disease, aortic dissection, and pulmonary embolism.

The history should include questions about the quality and location of the chest discomfort. The patient should also be asked about the nature of onset of the pain and its duration. Myocardial ischemia is usually associated with a gradual intensification of symptoms over a period of minutes. Pain that is fleeting or that lasts hours without being associated with electrocardiographic changes is not likely to be ischemic in origin.

The physical examination should include evaluation of blood pressure in both arms and of pulses in both legs. Poor perfusion of a limb may be due to an aortic dissection that has compromised flow to an artery branching from the aorta. Chest auscultation may reveal diminished breath sounds; a pleural rub; or evidence of pneumothorax, pulmonary embolism, pneumonia, or pleurisy. The cardiac examination should seek pericardial rubs, systolic and diastolic murmurs, and third or fourth heart sounds.

An electrocardiogram is an essential test for adults with chest discomfort that is not due to an obvious traumatic cause. The presence of electrocardiographic changes consistent with ischemia or infarction is associated with high risks of acute myocardial infarction or unstable angina such patients should be admitted to a unit with electrocardiographic monitoring and the capacity to respond to a cardiac arrest. The absence of such changes does not exclude acute ischemic heart disease, but the risk of life-threatening complications is low for patients with normal electrocardiograms or only nonspecific ST-T-wave changes. If these patients are not considered appropriate for immediate discharge, they are often candidates for early or immediate exercise testing.

Markers of myocardial injury are often obtained in the emergency department evaluation of acute chest discomfort. The most commonly used markers are creatine kinase (CK), CK-MB, and the cardiac troponins (I and T). Single values of these markers do not have high sensitivity for acute myocardial infarction or for prediction of complications. Hence, decisions to discharge patients home should not be made on the basis of single negative values of these tests.

Provocative tests for coronary artery disease are not appropriate for patients with ongoing chest pain. In such patients, rest myocardial perfusion scans can be considered; a normal scan reduces the likelihood of coronary artery disease. Clinicians frequently employ therapeutic trials with sublingual nitroglycerin or antacids, and a common error is to assume that a response to either of these interventions clarifies the diagnosis. While such information is often helpful, the patient's response may be due to the placebo effect. Hence, myocardial ischemia should never be considered excluded solely because of a response to antacid therapy. Similarly, failure of nitroglycerin to relieve pain does not exclude the diagnosis of coronary disease.

If the patient's history or examination is consistent with aortic dissection, imaging studies to evaluate the aorta must be pursued promptly because of the high risk of catastrophic complications with this condition. A chest x-ray is not sufficient to exclude this diagnosis. Appropriate tests include a chest computed tomography scan with contrast or a magnetic resonance imaging scan in patients who are hemodynamically stable, or a transesophageal echocardiogram in patients who are less stable. Aortic angiography is no longer a first test at most institutions.

Acute pulmonary embolism should be considered in patients with respiratory symptoms, pleuritic chest pain, hemoptysis, or a history of venous thromboembolism or coagulation abnormalities. Initial tests usually include a lung scan and/or pulmonary arteriography.

If patients with acute chest discomfort show no evidence of life-threatening conditions, the clinician should then focus on serious chronic conditions with the potential to cause major complications, the most common of which is stable angina. Early use of treadmill exercise testing for such patients, whether in the office or the emergency department, is now an accepted management strategy for low-risk patients. Exercise testing is not appropriate, however, for patients who (1) report pain that is believed to be ischemic occurring at rest or (2) have electrocardiographic changes consistent with ischemia not known to be old.

Patients with sustained chest discomfort who do not have evidence for life-threatening conditions should be evaluated for evidence of conditions likely to benefit from acute treatment. Pericarditis may be suggested by the history, physical examination, and electrocardiogram . Clinicians should carefully assess blood pressure patterns and consider echocardiography in such patients to detect evidence of impending pericardial tamponade. Chest x-rays can be used to evaluate the possibility of pulmonary disease.