Chest pain of undetermined origin.

Chest pain of undetermined origin (CPUO) can be a diagnostic dilemma for both the primary care physician and subspecialist. This article focuses on the diagnostic tools used in the evaluation of CPUO, which include: prolonged ambulatory intraesophageal pH monitoring; esophageal manometry with provocative testing; ambulatory intraesophageal pressure monitoring; the role of radiology and endoscopy in the evaluation of chest pain; the role of psychological abnormalities and abnormal nociception in the pathogenesis of chest pain; and the clinical approach and treatment rationale for CPUO.