Recent studies that utilized distension/contraction plots to study peristalsis reveal poor distension of the esophagus in patients with functional dysphagia and high-amplitude contractions [high-amplitude esophageal contractions (HAECs)] even though the contraction phase of peristalsis is normal in these patients. Our goal was to determine biomechanical properties of the esophageal wall and bolus flow characteristics in patients with functional dysphagia and HAEC during primary peristalsis. Studies were performed on 30 healthy subjects, 30 patients with functional dysphagia, and 25 patients with HAEC. Subjects swallowed 10 mL, 0.5 N saline bolus in the Trendelenburg position to study primary peristalsis. A custom-built software (Dplots) determined peak distension from the impedance measurements, pressure at peak distension, wall tension (pressure × radius), wall distensibility [cross-sectional area (CSA)/pressure], and bolus flow (cm3/s) in four segments of esophagus (between upper and lower esophageal sphincter). Luminal CSA of distal esophagus was smaller, and average bolus flow rate was faster in patients with functional dysphagia and HAEC. Esophageal wall distensibility, a measure of esophageal wall compliance was lower and wall tension was higher in the distal esophagus of both patient groups compared with normal subjects. Ultrasound imaging confirmed poor distension of the esophagus. A trend toward greater wall thickness at the peak of distension was found in patients with functional dysphagia compared with normal subjects. A stiffer or noncompliant esophageal wall is the reason for poor distension of the esophagus during primary peristalsis in patients with functional dysphagia and HAEC.

NEW & NOTEWORTHY We studied healthy asymptomatic subject, patients with functional dysphagia (FD), and patients with high-amplitude esophageal contractions (HAEC). Our data show that in patients with HAEC and functional dysphagia, luminal distension is smaller (low luminal CSA at peak distension), intraluminal pressure is higher, and liquid bolus travels faster through the esophagus as compared with normal subjects. We conclude that patients with functional dysphagia and HAEC have a stiffer distal esophageal wall during bolus transport related to primary peristalsis.