Electromyography of human oesophageal smooth muscle.

The aim was to study whether electromyography (EMG) activity is synchronous with oesophageal motor activity as assessed by manometry from the same oesophageal site. Patients with different motor disorders of the oesophagus and control subjects were investigated. EMG recordings were made by means of a suction capsule with silver/silver chloride spike electrodes. Slow EMG waves synchronous with respiration were recorded from the lower oesophageal sphincter and intermittently from the body of the oesophagus. Edrophonium increased spike discharges; atropine diminished or abolished spike discharges after swallowing. Swallowing caused a burst of spiking activity which began immediately after deglutition. Continuous sips of water produced constant EMG activity but no peristaltic contractions as seen by manometry. In a patient with scleroderma and aperistalsis, swallowing elicited vigorous electrical activity. The different EMG findings without simultaneous contractions at manometry are interpreted as a response to a swallow by the longitudinal muscle of the oesophagus.