This is an observational retrospective study to describe the association between cardiorespiratory (CR) and gastroesophageal reflux (GER) events in infants who underwent synchronized 24h Multichannel Intraluminal Impedance/pH-metry (MII/pH) and CR monitoring for GER disease symptoms and CR events. Data are collected from medical records and database of the University Neonatal Intensive Care Unit of the Sant'Anna-Regina Margherita Children Hospital (Turin).