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 pathol ogical 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 se rosa. The GB pressure was measured by a perfused catheter introduced t hrough the fundus. The response of the myoelectrical activity of the G B to balloon distension was tested and the direction of electrical wav es was defined by GB myotomies. Pacesetter potentials (PPs) were recor ded exhibiting the same frequency, amplitude and velocity of conductio n from the three electrodes of each dog on all test days. Action poten tials (APs) followed the PPs randomly and were associated with a rise of the GB pressure. Balloon distension of the GB caused increased PP a nd AP frequency. The electrical waves showed proximally but not distal ly to GB myotomy, indicating that they propagate proximo-distally towa rds the cystic duct. To conclude, the GB possesses electrical waves wh ich are probably initiated from a 'pacemaker' at the GB fundus. A norm al EChG could be characterized in the canine model. It is suggested th at this EChG might show changes in gall bladder diseases and might thu s act as an investigative tool, provided it can be developed to be per formed percutaneously.