Outcome of patients with a final diagnosis of chest pain of undetermined origin admitted under the suspicion of acute coronary syndrome: a report from the Rochester Epidemiology Project.

STUDY
OBJECTIVES: Patients presenting to the emergency department (ED) with chest pain after a recent negative inpatient evaluation for cardiac pathology represent a dilemma for the emergency physician. The purposes of this study were to assess the outcome of patients discharged with a diagnosis of chest pain of undetermined origin and to identify predisposing factors for further cardiac events.
METHODS: The resources of the Rochester Epidemiology Project were used to identify all admitted ED patients with chest pain with suspected acute coronary syndrome who received a discharge diagnosis of chest pain of undetermined origin from 1985 through 1992. Patient records were reviewed for the occurrence of adverse cardiac events and subsequent ED visits for recurrent chest pain within 12 months of discharge. Associations between patient characteristics and an adverse cardiac event were evaluated univariately and summarized by using odds ratios (ORs). Long-term mortality was also determined.
RESULTS: Among 1,973 admitted ED patients with chest pain, 230 were given a diagnosis of chest pain of undetermined origin. Ten (4.4%) of 230 patients experienced an adverse cardiac event. Factors significantly associated with an adverse cardiac event included an abnormal ECG on admission (OR 9.5; 95% confidence interval [CI] 2.0 to 45.8), preexisting diabetes mellitus (OR 7.1; 95% CI 1.8 to 27.2), and preexisting coronary artery disease (OR 28.4; 95% CI 3.5 to 229.0). Thirty-three (14%) patients returned to the ED within 12 months of discharge; 5 patients were given a diagnosis of a cardiac condition, and 5 were given a diagnosis of a gastrointestinal condition. In long-term follow-up, 46 patients died, with a mean time from hospital discharge to death of any cause of 6.1 years and an estimated 5-year survival of 91.4%.
CONCLUSION: Among patients discharged from the hospital with a diagnosis of chest pain of undetermined origin, those with an initial abnormal ECG, preexisting diabetes, or preexisting coronary artery disease are at higher risk of a subsequent adverse cardiac event. In the absence of such factors, cardiac outcome is excellent.