Multiple rapid swallowing in idiopathic achalasia : evidence for patients' heterogeneity

In order to evaluate the function of inhibitory neural pathways in achalasia, we compared the response of the oesophageal body and lower oesophageal sphincter (LOS) to single swallows (SS) and multiple rapid swallowing (MRS) in 20 consecutive patients with untreated idiopathic achalasia (10 men, aged 23-81 years) and in 20 control patients without dysphagia (nine men, aged 31-73 years), using sleeve manometry; 277 SS and 85 MRS were analysed. In the control group, MRS inhibited motor activity in the oesophageal body and induced a slightly lower (P < 0.05) nadir LOS pressure compared with SS. In the achalasia patients, MRS induced a variable response: eight patients had simultaneous motor activity during all MRS although onset was delayed compared with SS [median (interquartile range), 3.5 s (1.7-6.1) vs 1.4 s (0.8-3.9); P < 0.05], whereas eight patients showed motor inhibition which occurred during all MRS in four of them, and the remaining four had no motor activity both after SS and during MRS. Overall MRS did not decrease nadir LOS pressure compared with SS [12 mmHg (5-20) vs 16 mmHg (7-22); P > 0.1]; however, it induced complete LOS relaxation in three of the patients. MRS gives further evidence of functional heterogeneity among achalasia patients.