Achalasia (Cardiospasm; Esophageal Aperistalsis; Megaesophagus) By Kristle Lee Lynch, MD, Perelman School of Medicine at The University of Pennsylvania Reviewed / Revised Mar 2022 | Modified Sep 2022 View Patient Education Symptoms and Signs Diagnosis Prognosis Treatment Key Points More Information Topic Resources Barium Swallow Showing Dilated.. Achalasia is a neurogenic esophageal motility disorder characterized by impaired esophageal peristalsis and a lack of lower esophageal sphincter relaxation during swallowing.