Key Clinical Questions
What signs and symptoms point to a serious cause of cardiogenic chest pain?
What key historical elements will help to narrow the differential diagnosis?
What studies should be ordered to evaluate a patient presenting with suspected cardiac ischemia?
According to the 2006 National Hospital Ambulatory Medical Care Survey, 6,392,000 patients presented to emergency departments (ED) with a chief complaint of chest pain or related symptoms. Of those, 1,976,000 patients were admitted to the hospital, with a mean length of stay of 3.7 days. Chest pain was the principal admitting diagnosis in 5.4% of all admitted patients.
Because morbidity and mortality is high if clinicians “miss” a cardiac presentation of chest pain, a significant portion of these admissions are specifically for the purpose of ruling out myocardial ischemia or infarction. In one study of patients presenting to an emergency department with complaints consistent with cardiac ischemia, 17% ultimately had cardiac ischemia, while 27% had stable angina or other cardiac conditions. Fifty-five percent had noncardiac conditions diagnosed as the cause of their symptoms. The wide differential diagnosis for this heterogeneous group of patients includes nonischemic life-threatening etiologies as well as more benign causes. Despite the focus on cardiac causes, in this study, 2.1% of the patients with acute myocardial infarction were erroneously discharged; this figure and the concern it generates may play prominently in the low threshold to admit patients with chest pain.
Chest pain also occurs in patients already admitted to the hospital for other reasons. These patients have already suffered some degree of physical decompensation and an occurrence of chest pain may indicate illness, a complication of hospitalization, or a patient’s response to a very stressful situation. The hospitalist must evaluate the possibility of an immediate life-threatening event, consider the entire differential of possible etiologies, and integrate this information with the patient’s prior clinical diagnoses and course. The focus of this chapter will be on the initial evaluation of patients presenting with chest pain, specifically targeting the investigation of cardiac ischemia in those patients.
The initial evaluation of a patient reporting chest pain requires the rapid identification and treatment of any life-threatening conditions. These include the five “do-not-miss” causes of chest pain: (1) aortic dissection, (2) acute myocardial infarction (MI), (3) pulmonary embolism (PE), (4) pneumothorax, and (5) esophageal rupture (Table 79-1). The electrocardiogram (ECG) is one of the most important screening tests for early risk stratification and is often performed at the point of triage as one of the “vital signs.”
TABLE 79-1Life-Threatening Causes of Chest Pain ||Download (.pdf) TABLE 79-1 Life-Threatening Causes of Chest Pain
|Diagnosis ||Risk Factors ||Characteristic Findings ||Diagnostic Testing |
|Aortic dissection ||Hypertension, connective tissue disease, vasculitis, prior heart or valvular surgery, Turner syndrome, ...|