Spike-associated and spike-independent esophageal contractions in patients with symptomatic diffuse esophageal spasm

We report the electrical correlates of esophageal and lower esophageal sphincter contraction in humans using a bipolar ring electrode assembly mounted on a catheter. No spike activity was seen in the resting state in the esophagus or lower esophageal sphincter. Swallowing induced both electrical spike activity and contractile activity in both areas. The delay in the proximal and distal esophagus from swallowing to the onset of electrical activity was 0.3 ± 0.1 s and 3.3 ± 0.2 s, respectively, and from swallowing to the onset of contractile activity the time was 1.9 ±0.1 s and 5.2 ± 0.2 s, respectively. The rate of propagation of electrical activity was constant throughout the esophageal body while contractile activity was propagated more rapidly in the middle third of the esophagus. Spike activity preceded the peak of esophageal contractions in 100% of swallows. Lower esophageal sphincter relaxation was initiated without spike activity, but the postswallow lower esophageal sphincter contraction was preceded by spike activity in 100% of cases. Basal lower esophageal sphincter pressure was maintained in the absence of spike activity. Spontaneous esophageal contractions, seen in patients with symptomatic diffuse esophageal spasm, were spike-independent in 70% of cases. Prolonged repetitive contractions, once initiated, were also spike-independent. Thus, with the use of intraluminal ring electrodes, we suggest that the human esophagus and lower esophageal sphincter are capable of generating both spike-dependent and spike-independent contractions. The latter may be prominent in patients with esophageal motor disorders.