Retrospective analysis for HRM measurements using liquid swallows and a test meal for the presence of hiatal hernia. The investigators will correlate hernia descriptions with presence of acidic reflux and clinical complaints.

We will retrospectively analyze all patients referred to hour unit for high-resolution esophageal manometry. These patients have been tested using liquid swallows and a test meal. We will analyze the HRM measurements for presence of manometric signs of hiatal hernia and determine predictive factors for hernia presence. We will correlate hernia description versus presence of acid reflux, clinical complaints and HRM measurements.

Inclusion Criteria:

• All patients referred to our functional lab for esophageal high-resolution manometry from January 2013 - December 20165
• Lack of documentation of patient preferences against usage of medical data for biomedical research
• Male and female patients ≥18 years of age

Exclusion Criteria:

• Age under 18 years
• Patient's wishes against scientific use of their clinical data

Patients referred to hour unit for high resolution manometry (patients with dysphagia, reflux or other complaints)