The etiology of achalasia is not clearly defined and there is still no cure. All treatment options are to relax the lower esophageal sphincter (LES) and the cardia sphincter to relieve the clinical symptoms of the patient. Available therapeutic agents include smooth muscle relaxants, such as nitrates or calcium antagonists, which have limited action and significant side effects. Endoscopic treatment of achalasia of the cardia is widely used in clinical practice because of its minimal invasiveness, rapid postoperative patient recovery, and significant symptom relief. The pathogenesis of cardia achalasia is mainly related to the imbalance between excitatory and inhibitory nerve levels in the intermuscular plexus of esophageal smooth muscle. Selective destruction of inhibitory ganglia can lead to loss of lower esophageal flaccidity and an organic abnormality of the esophagus from complete absence of contraction to marked esophageal spasm. Although patients typically present with dysphagia and chest pain, they can also present with GERD-like symptoms such as reflux, heartburn and nocturnal cough. As a result, many patients are misdiagnosed with GERD and the presence of cardia can be considered when the patient is not responding to proton pump inhibitors. Esophageal manometry should be considered in the presence of dysphagia and refractory GERD symptoms when endoscopy is normal. Diagnostic Recommendations 1. In patients with suspected cardia failure, esophageal kinetic testing should be performed before confirming the diagnosis if there are no positive findings on endoscopy or esophageal x-ray. (Strongly recommended, supported by low-quality evidence.) 2. The diagnosis of cardia is supported by the following findings on esophageal X-ray: dilatation of the esophagus; narrowing of the esophagogastric junction (EGJ) with a “beak sign”; loss of esophageal peristalsis; and poor emptying of the barium esophagus. (Strongly recommended, supported by moderate quality evidence.) 3. For patients with suspicious esophageal kinetic test results, barium swallow X-ray is recommended to assess esophageal emptying function and EGJ morphology. (Strongly recommended, supported by low-quality evidence) 4. In all patients with cardia failure, esophageal endoscopy should be performed to visualize the EGJ and gastric cardia morphology to exclude pseudo cardia failure. (Strongly recommended, supported by moderate quality evidence) Treatment measures Endoscopic balloon dilation Endoscopic esophageal dilation is the traditional method for the treatment of achalasia of the cardia. The commonly used method of dilation is gas balloon dilation, and the number and duration of dilation must depend on the operator and the need for successful dilation. The advantage of this method is that it provides significant near-term results and rapid symptom relief in most patients. Clinical studies have shown that its recent efficacy is comparable to that of laparoscopic Heller myotomy. In addition, this method has a better safety profile and fewer complications. Recent studies have shown that gas balloon dilation remains an effective and safe treatment for patients who have failed or recurred from laparoscopic Heller myotomy. The disadvantage is that a significant proportion of patients still present with distant (more than 12 months) recurrence. Possible risk factors for recurrence include being young (under 45 years of age), being female, performing a single dilation with a small diameter balloon, having a post-treatment LES pressure above 10-15 mmHg, having a real-time barium esophageal meal showing poor esophageal emptying, and having HRM showing type I and III cardia achalasia. In addition, complications such as perforation and bleeding may occur with gas balloon dilation. Transoral endoscopic myotomy (POEM), which has been performed at our institution for many years with remarkable results, can be performed by me. The endoscopic myotomy for cardia was first described by Ortega in 1980, and was later modified for clinical use by Japanese scholars such as Kiyoyo Inoue in 2010, after animal experiments. The general steps are: after incising the esophageal mucosa at the proximal end of the esophagus, the submucosal layer is separated to create a submucosal tunnel, the internal circular muscle is peeled and incised, and finally the mucosal tunnel opening is closed with a metal titanium clip (Figure). (Figure POEM procedure (A esophageal mucosal dissection, B separation of the submucosal layer to create a tunnel, C esophageal circumferential muscle dissection, D closure of the incision with a metal titanium clip) The advantages of this method are that myotomy can be performed without a skin incision, less trauma, fewer complications, and significant recent results with significant symptom relief in patients. A recent prospective, international multicenter study showed that after 3 months of POEM treatment, 97% of patients showed significant reduction in clinical symptoms and LES pressure, and after 1 year of follow-up, 82% of patients showed significant symptom relief. Compared with laparoscopic Heller myotomy, POEM enables deeper myotomy through the thoracic segment of the esophagus and is particularly indicated in patients with progressive disease and in the presence of fibrosis. In addition, the latter is less likely to cause damage to the vagus nerve. The main complications of POEM are subcutaneous emphysema, pneumothorax, and septic mediastinitis. The long-term efficacy of POEM and the comparison with the efficacy of conventional treatments require further observational studies.