Electrocholedochogram: a study of the electromechanical activity of the common bile duct in the dog

The electromechanical activity of the common bile duct (CBD) was studied in 11 dogs aiming at elucidating the mechanism of bile transport through the CBD as well as at characterizing a normal electrocholedochogram that could act as a standard for the pathologic conditions. After opening the abdomen under anesthesia and exposing the CBD, the electric activity of the CBD was recorded by 2 electrodes sutured to its serosa and the pressure registered by a perfused catheter introduced into the CBD. The effect of CBD distention and myotomy on its EMG activity was tested. Slow waves or pacesetter potentials (PPs) were recorded exhibiting the same frequency, amplitude, and velocity of conduction from the 2 electrodes of each dog on all test days. They were followed by action potentials (APs) which were inconsistent and associated with a rise in the CBD pressure. These variables were higher postcibally than in the fasting state (p < 0.05). They increased on balloon-produced distention of the CBD. The caudad direction of PPs and APs was evident when, following the CBD myotomies, the signals appeared from the segment proximal but not distal to the cut. The study demonstrated that the CBD possesses an electric activity which seems to be responsible for the motile activity of the duct. Furthermore a normal "electrocholedochogram" was characterized which is expected to exhibit changes in pathologic conditions of the CBD. It is proposed that the electrocholedochogram could act as an investigative tool in the diagnosis of CBD disorders, provided it could be performed transcutaneously.