Characteristics of the propagating pressure wave in the esophagus.

Understanding the relationships of intraluminal manometric events to bolus transit through the esophagus has been limited by conventional manometric analysis methods. We reconstructed pressure events in the axial direction in order (1) to describe the peristaltic pressure wave as it propagates through the esophagus in the direction of the bolus and (2) to determine what sampling interval along the esophageal length is required for accurate representation. Esophageal manometric studies using the stepwise withdrawal method were performed in 10 asymptomatic volunteers. Propagating wave forms were created at 0.2-sec intervals and analyzed in static and dynamic fashion from averaged waves at each 1-3 cm of esophageal length. A distinctive and similar appearance to the propagating wave form, comprised of three sequential but overlapping contraction segments in the esophageal body, was present in nine subjects. The propagating wave decelerated as it approached the second region (smooth-muscle esophagus) and extended over as much as 15.1+/-0.7 cm of esophageal length. No significant differences in wave front propagation, length, or velocity could be determined if the sampling interval increased from 1 to 3 cm of esophageal length, but peak amplitudes were reduced by as much as 14.2%. We conclude that the esophageal pressure wave, when viewed in the direction of bolus transit, is broad and typically comprised of three sequential contraction components. Sampling at >1-cm intervals along the esophageal length significantly alters the wave appearance and may be unsatisfactory in the distal esophagus. Axial transformations of manometric data potentially will provide better information concerning the neuromuscular control of peristalsis and events responsible for bolus movement.