24-hour oesophageal multichannel impedance and pH monitoring is the gold standard in the diagnostic process of gastroesophageal reflux disease. Together with oesophagogastroduodenoscopy, it enables to distinguish different kinds of this disease and implement appropriate treatment. Recently, thanks to impedance, it was attempted to evaluate new parameters that could be helpful in diagnosis of gastroesophageal reflux disease and its differentiation from functional heartburn. One of these parameters is baseline impedance. It is measured when no swallows and refluxes occur in the oesophagus, i.e. when the oesophageal wall stays still. Postreflux swallow-induced peristaltic wave (PSPW) index is another parameter measured in 24-hour oesophageal multichannel intraluminal impedance and pH-monitoring. It is a quotient of the number of reflux episodes with postreflux swallow-induced peristaltic wave and the total number of reflux episodes. It was proven that baseline impedance and postreflux swallow-induced peristaltic wave index are correlated with oesophageal mucosa integrity. Values of these parameters differ in healthy volunteers, patients with functional heartburn as well as with erosive and nonerosive gastroesophageal reflux disease. They may be useful in the diagnosis, but also in making decisions about pharmacological or surgical treatment. These parameters are not evaluated during 24-hour oesophageal multichannel impedance and pH-monitoring on a routine basis. Since the available studies have been carried out on small groups of patients, there is a need for further investigation to assess the diagnostic value of baseline impedance and PSPW.

gastroesophageal reflux disease, reflux, baseline impedance, postreflux swallow-induced peristaltic wave