Inclusion Criteria:  18 to 65 years old; History of typical GERD symptoms (heartburn or regurgitation) during PPI treatment, at least 3 times per week for 12 weeks ('refractory GERD') or unwillingness to take/continue PPIs. The symptoms can be de novo (onset after sleeve gastrectomy) or pre-existing (as documented by medication use, findings during endoscopy or medical history); In case of refractory GERD symptoms during PPI treatment the following criteria need to be fulfilled: Pathological catheter-based 24h pH-MII monitoring off-PPI (>6% of total time pH<4 and/or number of reflux episodes >80 (irrespective of acidity) or positive symptom association probability (SAP) for typical reflux symptoms) based on the Lyon consensus (23); More than 12 months after sleeve gastrectomy; Willing to take contraceptive measurements.  Exclusion Criteria:  Hiatal hernia of >2cm as determined during HRiM (based on Chicago Classification v3.0. (24)) and/or endoscopy or hiatal hernia repair; Esophagitis LA classification grade C or D during gastroscopy off-PPI; Circumferential Barrett's esophagus >1cm (columnar lined esophageal mucosa with intestinal metaplasia) or history of ablation of Barrett's esophagus; Esophageal or fundus varices during gastroscopy; Esophageal strictures during gastroscopy; Abnormalities in sleeve (e.g. sleeve migration) observed during gastroscopy and/or barium test; Known cirrhosis or portal hypertension from other causes; History of surgery to the upper gastrointestinal tract other than sleeve gastrectomy, including redo after previous bariatric surgery; Autoimmune or a connective tissue disorder (scleroderma, dermatomyositis, Calcinosis-Raynaud's-Esophagus Sclerodactily Syndrome (CREST), Sjogren's Syndrome, etc.); Achalasia, EGJ-outflow obstruction, jackhammer esophagus or absent contractility as defined by the 3rd revision of the Chicago classification for primary esophageal motility disorders24 assessed during HRiM with meal (see study protocol (25)); Significant cardiopulmonary or other comorbidity precluding safe sedation; Pacemaker or implanted cardiac defibrillator; Coagulopathy or use of anticoagulants; Pregnancy or breastfeeding Unable or unwilling to consent for an invasive procedure.