Pathogenesis of simultaneous esophageal contractions in patients with motility disorders.

BACKGROUND: Simultaneous and spontaneous contractions are frequently recorded in patients with esophageal motility disorders. The aim was to investigate the pathogenesis of swallow-induced simultaneous and spontaneous contractions.
METHODS: The pathogenesis was studied in patients with normal peristaltic contractions (control group) and in patients with functional dysphagia with either simultaneous contractions (group A), with peristaltic but prolonged contractions (group B), and with frequent spontaneous contractions (group C).
RESULTS: Simultaneous contractions had latencies of 2.9 +/- 0.2 seconds compared with 6.4 +/- 0.2 seconds for normal peristaltic contractions and 5.8 +/- 0.4 seconds for prolonged peristaltic contractions. Paired swallows at intervals of 5 seconds generated one peristaltic sequence after the second swallow in subjects with normal peristalsis and two sets of contractions in patients with simultaneous contractions. Ten consecutive swallows taken at 5-second intervals inhibited the spontaneous contractions evoked by bethanechol in control subjects but had no significant effect on the spontaneous contractions of subjects with simultaneous contractions. Atropine reduced the frequency, force, and duration of the spontaneously generated contractions in group C.
CONCLUSIONS: The shorter latency of simultaneous contractions may be caused by a defective deglutitive inhibitory reflex, and spontaneous contractions appear to be generated by swallow independent discharges of acetylcholine.