Study Hypothesis:

This study is designed as an integral part of the development of new or improved features or components of the Bravo® pH Monitoring System and may serve verification and validation purposes The study population will include a group of healthy volunteers (Group A) and a group of symptomatic patients with known or suspected gastroesophageal reflux disease (Group B).

Group A: Healthy volunteers will not undergo invasive procedure. These volunteers may be asked to carry the capsule and\or Bravo Recorder. These procedures will serve to evaluate different technical matters such as human interface, ergonomic aspects and communication performances of the system Group B: Symptomatic patients will undergo invasive procedure, including Bravo capsule delivery, positioning and attachment. Confirmation of capsule attachment may be done by endoscopically.

These procedures will serve to evaluate overall system performance in actual clinical setup, for instance: Bravo Recorder performance including communication quality, human interface and similar, ergonomics of delivery device, pH Capsule performance, etc.

Subjects from both study groups as well as physician may be asked to provide feedback on the procedure and/or document their activities during the procedure.

Up to a total of 220 subjects will participate in this study. The study will include two separate population groups. Group A of up to 170 healthy volunteers and Group B of up to 50 symptomatic patients with known or suspected gastro esophageal reflux disease.

Inclusion Criteria:

1. Subject age ≥ 18 years old

2. Subject received an explanation about the nature of the study and agrees to provide written informed consent.

   Group A (healthy volunteers) Only

3. Subject is an healthy volunteer

Group B (symptomatic patients) Only 1. The subject was referred for pH monitoring procedure to detect acid reflux for at least one of the following reasons:

• Burning substernal chest pain (heartburn)
• Regurgitation of food or stomach contents
• Dysphagia
• Epigastric pain
• Non-erosive reflux disease (NERD)

Exclusion Criteria:

Group A and B-

1. Subject has a cardiac pacemaker or other implanted electromedical device.

2. Subject has any condition, which precludes compliance with study and/or device instructions.

3. Women who are either pregnant or nursing at the time of screening, or are of child-bearing potential and do not practice medically acceptable methods of contraception.

4. Subject suffers from life threatening conditions

5. Subject currently participating in another clinical study which may interfere with study objectives, per physician discretion

   Additional exclusion criteria for Group B only

6. Subject has prior abdominal surgery other than uncomplicated procedures that would be unlikely to lead to bowel obstruction based on the clinical judgment of the investigator

7. Subject is schedule to undergo MRI examination within 30 days from pH monitoring procedure.

8. Subject has known bleeding diathesis, strictures, severe esophagitis, varices and or obstructions -