In a patient with severe heartburn and negative H. pylori stool test, what should be the next step in investigation?

Considering the scenario where a patient presents with severe heartburn and has already undergone a stool test for H. pylori that returned negative, the most appropriate next step in investigation would be oesophageal manometry.

Oesophageal manometry is a test that measures the functionality of the esophagus and assesses the muscular contractions during swallowing. It is particularly relevant in cases of severe heartburn where gastroesophageal reflux disease (GERD) is suspected, but where typical treatment or findings (like a negative H. pylori test) do not adequately explain the symptoms. This investigation can reveal motility disorders such as achalasia or esophageal spasm, which could contribute to the patient's heartburn symptoms.

By contrast, endoscopy could be considered in cases where there are more concerning symptoms or in the presence of potential complications, such as ulcers or strictures, but it might not be the immediate next step if the primary concern is to evaluate functional motility. Similarly, an ultrasound isn’t pertinent in this context since it pertains more to abdominal organ evaluation rather than esophageal function. Initiating pantoprazole therapy may be appealing for symptom relief; however, it doesn't investigate the underlying cause of the severe heartburn and could mask other significant conditions if not appropriately