Vagal Function in Achalasia of the Cardia

Autonomic nervous function in achalasia of the cardia was assessedby measuring the response of the lower oesophageal sphincterto abdominal compression, the gastric secretory response toinsulin-induced hypoglycaemia and the pulse rate variabilitywith deep respiration. Twenty-eight patients with symptomaticachalasia and 24 age and sex-matched control subjects were studied. Rise in intra-abdominal pressure normally causes a reise inlower oesophageal pressure through a vagally-mediated mechanism.Before treatment this response was unimpaired in eight of 10patients with achalasia. A sub-normal response was found ineight of 10 patients who had previously had pneumatic dilatationof the cardia and in three of four who had had a cardiomyotomy.These abnormalities reflected the effect of treatment in disruptingthe sphincter rather than impairment of its innervation. Thegastric acid secretory response to insulin-induced hypoglycaemia,expressed as a ratio of that to pentagastrin, was normal, ineach of the nine patients studied. Pulse rate variability withdeep respiration, a test of cardiac vegal function, was normalin 22 of 25 patients studied. It is concluded that in achalasia the vagal trunks appear functionallyintact and that the myenteric plexus lesion rarely affects theresponsiveness of the lower oseophageal sphincter to increasein intra-abdominal pressure.