A STUDY OF THE HUMAN ELECTROGASTROGRAM USING CUTANEOUS ELECTRODES

Abstract

Since Alvarez first recorded the el ectrical waves from the human stomach in 1922, many investigators, both basic scientists and clinicians have contributed to our understanding of the eletrophysiology of the stomach. These studies have ranged from recordings of electrical activity from within the cell to recordings from the intact stomachs of man and animals. Various investigators have attempted to apply this knowledge to the study of human gastric physiology and abnormalities of the stomach, such as gastric ulcer, gastric carcinoma, and dumping syndrome. Many of the early investigators in the United States used cutaneous or swallowed electrodes, and their analysis of the electrogastrograms primarily stressed the variations of wave form, the DC potential, and the amplitudes of the waves with minimal analysis of rate variations. By the nature of the recordings obtainable with their electrodes and their method of recording, in light of our present understanding of electrophysiology of smooth muscle and electrodes, some of their data are difficult to interpret. Several groups in Japan have improved upon the swallowed electrode and have been able to obtain good electrical recordings from the human stomach. The analysis of their electrogastrograms have emphasized variations of wave form, amplitude, conduction, and also the variations of rate. The findings in normals and the variations from the normal in certain gastric abnormalities suggest the clinical possibilities of the electrogastrogram. We too became interested in studying the electrophysiology of the human stomach several years ago. We started our studies with swallowed electrodes, but found that many of our subjects would not tolerate a tube for any length of time and often became nauseated. In addition we were interested in studying the response of the stomach to a meal, and felt that it would be better not to have a tube within the stomach. We appreciated the disadvantages of the cutaneous electrodes, but we were primarily interested in obtaining electrogastrograms adequate for analysis of rate variations. The following study was undertaken to: 1) evaluate the efficacy of a cutaneous electrode; 2) establish the fasting rate of normal subjects using this electrode; and 3) determine the pattern of electrical rate change following ingestion of a meal.