Achalasia, also known as esophageal achalasia, achalasia cariae, cardiospasm, dyssynergia esophagus, and esophageal aperistalsis, is an esophageal motility disorder, a disease in which normal movement of the muscles in the esophagus is disturbed. It is characterized by difficulty swallowing, chest pain and regurgitation. Diagnosis is reached with esophageal manometry. Various treatments are available, but none cure the condition completely. Certain medications may be used, as well as injection of the esophageal muscles with botulinum toxin, but more permanent relief is brought by esophageal dilatation and surgical cleaving of the muscle (e.g. a procedure known as Heller myotomy).