PREcision MEDicine In Achalasia (PREMEDIA) - Cohort

The goal of this observational study is to learn about how the doctor decides how long to cut t the esophageal muscle during Per-Oral Endoscopic Myotomy (POEM) in patients with difficulty swallowing due to certain conditions. The main question it aims to answer is: does pre-POEM testing help the physician choose how long to cut the muscle. Participants will allow researchers to access their standard of care information in their medical record, complete questionnaires at up to 6 times over a 2-year period.

Inclusion Criteria: 1. Age ≥ 18 2. Type III achalasia or EGJOO with spastic/hypercontractile features or Jackhammer Esophagus or Distal Esophageal Spasm 3. Eckardt Score \> 3 Exclusion Criteria: * Exclusion: 1. Prior POEM 2. Prior surgical treatment for achalasia 3. Endoscopic pneumatic dilation or lower esophageal sphincter botulinum toxin (botox) injection within 6 months 4. Prior unrelated esophageal or upper gastric surgery, including Roux-en-Y gastric bypass and sleeve gastrectomy 5. Prior endoscopic gastroesophageal intervention for obesity or GERD, such endoscopic sleeve gastroplasty or transoral incisionless fundoplication 6. Known secondary achalasia related to malignancy (pseudoachalasia) 7. Known eosinophilic esophagitis 8. Diverticulum (\> 2 cm) in distal esophagus 9. Megaesophagus 10. Fibroinflammatory stricture of the esophagus due to any etiology (e.g., peptic, radiation, eosinophilic) 11. Pregnancy 12. Standard contraindications to general anesthesia 13. Standard contraindications to endoscopic myotomy in the esophagus (e.g. untreated varices) 14. Unwillingness or inability to consent for the study 15. Anticipated inability to follow protocol