Millions of patients present to emergency departments (EDs) each year with acute nontraumatic chest pain. Varied clinical presentations coupled with a wide differential diagnosis make patients with chest pain some of the most challenging cared for by emergency care providers. An organized approach will assist clinicians when differentiating acute coronary syndrome (ACS) from other causes of chest pain.
Classically described cardiac chest pain is retrosternal in the left anterior chest with crushing, tightness, squeezing, or pressure that is often brought on by exertion and relieved with rest. Patients may also complain of dyspnea, diaphoresis, and nausea with pain radiating to the left shoulder, jaw, arm, or hand. Some patients, such as premenopausal and early menopausal women, racial minorities, diabetics, the elderly, and patients with psychiatric disease or altered mental status, may have nonclassic presentations of ACS that may or may not be associated with chest pain. Patients with acute myocardial infarction (AMI) who present without chest pain have diagnostic and treatment delays and a higher mortality rate compared to AMI patients who do have chest pain. The onset of symptoms attributed to cardiac disease may be sudden or gradual, and traditionally angina pain lasts 2 to 10 minutes, unstable angina lasts 10 to 30 minutes, and AMI pain often lasts longer than 30 minutes. Dyspnea at rest or with exertion, nausea, light-headedness, generalized weakness, acute changes in mental status, diaphoresis, or shoulder, arm, or jaw discomfort may be the only presenting symptoms for ACS for some patients.
Cardiac risk factors are useful in predicting coronary artery disease in patient populations but may be less useful when applied to an individual patient. Cocaine abuse and HIV infection can accelerate atherosclerosis. Classic symptoms such as radiation of pain to the arms, an exertional component, associated diaphoresis, nausea, and vomiting increase the likelihood that a patient is suffering from an AMI while other symptoms such as pain that is pleuritic in nature, positional, sharp and reproducible with palpation/positioning decrease the likelihood of disease. Unfortunately, there is no identifiable symptom complex that definitively rules in or out the disease without objective testing.
DIAGNOSIS AND DIFFERENTIAL
Patients with ACS often have a normal physical exam but may present with abnormal vital signs. Tachycardia may result from increased sympathetic tone and decreased left ventricular stroke volume. Bradycardia may result from ischemia to the conduction system. The degree of hemodynamic instability is dependent on the amount of myocardium at risk, associated dysrhythmias, or preexisting valvular or myocardial dysfunction. Patients with acute ischemia may have a third or fourth heart sound from changes in ventricular compliance, a new murmur from ruptured cordae tendineae or an aortic root dissection, or crackles on lung auscultation from congestive heart failure. Chest wall tenderness has been demonstrated in up to 15% of patients with AMI, making this physical examination finding unlikely to be useful by ...