Electrocholecystogram: a study of the electromechanical activity of the gall bladder in a canine model

To characterize an 'electrocholecystogram' (EChG) for the normal gall bladder (GB) that might act as a standard for the evaluation of pathological electrocholecystograms of the diseased GB, ten mongrel dogs (14.4+/-3.2 kg) were studied. Under anaesthesia, the abdomen was opened and three silver-silver chloride electrodes were sutured to the GB serosa. The GB pressure was measured by a perfused catheter introduced through the fundus. The response of the myoelectrical activity of the GB to balloon distension was tested and the direction of electrical waves was defined by GB myotomies. Pacesetter potentials (PPs) were recorded exhibiting the same frequency, amplitude and velocity of conduction from the three electrodes of each dog on all test days. Action potentials (APs) followed the PPs randomly and were associated with a rise of the GB pressure. Balloon distension of the GB caused increased PP and AP frequency. The electrical waves showed proximally but not distally to GB myotomy, indicating that they propagate proximo-distally towards the cystic duct. To conclude, the GB possesses electrical waves which are probably initiated from a 'pacemaker' at the GB fundus. A normal EChG could be characterized in the canine model. It is suggested that this EChG might show changes in gall bladder diseases and might thus act as an investigative tool, provided it can be developed to be performed percutaneously.