Source:http://linkedlifedata.com/resource/umls/id/C0687483
UMD: Electronic data storage recorders that include catheters (e.g., esophageal, biliary) and an electronic amplifier. There are two basic types of recorders: real time and retrospective, according to the point at which analysis is performed. These recorders are commonly used in ambulatory patients to correlate pH data (e.g., data related to gastroesophageal reflux) to patient symptoms.