Endoscopy Clinical Trials

The goal of this observational study is to learn whether heterotopic gastric mucosa (HGM) in the upper esophagus is associated with swallowing difficulties (dysphagia) in adults undergoing a medically indicated gastroscopy. The main questions it aims to answer are: * Is the presence of HGM associated with dysphagia? * Is the presence of HGM associated with dyspepsia and reduced health-related quality of life? Among participants reporting dysphagia, what is the distribution of oropharyngeal versus esophageal dysphagia, and is this related to the presence of HGM? If there is a comparison group: Researchers will compare participants with endoscopically confirmed HGM to participants without HGM to determine whether dysphagia, dyspepsia symptoms, and quality-of-life measures differ between groups. Participants will: Complete pseudonymised questionnaires about dysphagia, dyspepsia symptoms, and quality of life before the gastroscopy. Undergo the medically indicated gastroscopy as planned; the endoscopist will assess whether HGM is present based on the endoscopic appearance, and routine endoscopy findings will be documented.