30th April 2024

A 45-year-old male reports a 4-month history of frequent heartburn, especially at night, and a sensation of acid regurgitation into his throat.

A 45-year-old male reports a 4-month history of frequent heartburn, especially at night, and a sensation of acid regurgitation into his throat. These symptoms often occur after large meals and are partially relieved by over-the-counter antacids. He denies any difficulty swallowing, weight loss, or gastrointestinal bleeding. He is a non-smoker and drinks alcohol socially. His BMI is 30 kg/m^2.

Which investigation is most likely to confirm the diagnosis?