As living standards improve, the incidence of coronary heart disease is increasing. In daily life, many people experience unexplained chest pain, especially at night, and many patients are so severe that they need to see the emergency room again and again. Most patients with chest pain first think of heart problems, and many cardiologists have difficulty in distinguishing whether this chest pain is of cardiac origin, because this chest pain responds well to nitroglycerin, which is an effective drug for angina pectoris, so it is not easy to exclude non-cardiac chest pain without specialist examination for gastroesophageal reflux, and some patients are “misdiagnosed and mistreated” for this reason. Some patients have been “misdiagnosed and mistreated” for many years. Chest pain of esophageal origin is closely related to esophageal acid exposure: 10-70% of these patients are found to have esophageal mucosal erosion during gastroscopy. The application of anti-reflux therapy based on proton pump inhibitors (PPI) is effective in the treatment of 80% of patients with reflux esophagitis or abnormal 24-hour intraesophageal pH monitoring (pH < 4), suggesting that acid reflux is an important pathophysiological basis for the development of non-cardiogenic chest pain symptoms. However, a significant number of patients with non-erosive gastroesophageal reflux have no abnormalities on gastroscopy, and further studies have identified a number of patients with atypical chest pain associated with weak acid (ph > 4) and acid-free (pH > 7) reflux. The characteristics of esophageal-derived chest pain include: pain lasting more than 1 hour, mostly appearing after meals, no radiation, and may be accompanied by gastrointestinal symptoms such as heartburn, acid reflux, and dysphagia, and the chest pain symptoms can be relieved by the application of acid suppressants or antacids, but patients with predominantly weak acid or acid-free reflux have atypical chest pain symptoms or only present with symptoms such as chest tightness, pharyngeal discomfort, and foreign body sensation in the pharynx, and this group of patients is not effective against acid suppressants or The effect of antacids is also not satisfactory. A 36-year-old patient with chronic pharyngitis and frequent chest tightness was not cured for a long time, and the pH of the esophagus was found to be normal after examination, but the patient had 70 refluxes, basically weak acid reflux, and nearly 30% of the reflux range reached the pharynx. Reflux is predominant. Esophageal pH measurement is the gold standard for the diagnosis of GERD: however, it is only diagnostic for reflux with pH < 4 and reflux time more than 5 minutes, and it is not sensitive enough for many patients with weak acid reflux with pH > 4 or combined with alkaline reflux, and for short time reflux. The diagnosis rate of GERD can be greatly improved. Combined esophageal pH and impedance measurement: It is a good method to detect and diagnose GERD, the measurement process is relatively simple, only a catheter with a diameter as thick as a thin noodle is inserted into the esophagus through the nasal cavity and fixed at 5 cm above the lower esophageal sphincter, the patient only has a slight foreign body sensation in the pharynx, during the measurement period the patient During the measurement period, the patient can eat and drink normally, rest normally, and do not engage in strenuous activities, which is a simple and easy way to check GERD.