Characteristics of spontaneous and drug-induced gastric dysrhythmias in a chronic canine model.

We developed a chronic canine model to study electrical characteristics of both spontaneously occurring and drug-induced gastric dysrhythmias. Seven female dogs were fitted with a catheter chronically implanted in the left gastric artery, and five monopolar silver-silver chloride electrodes were sutured to the serosa of the stomach and proximal duodenum. Three dogs exhibited spontaneous dysrhythmia, and in 4 other dogs, dysrhythmias were drug-induced. Ninety-seven episodes of spontaneous dysrhythmia and 21 episodes of drug-induced dysrhythmia were recorded and analyzed. All episodes of tachygastria were first detected in the distal antrum, and the tachygastric pacesetter potentials usually spread orally. All but one episode of bradygastria were detected both in the corpus and the antrum simultaneously. During bradygastria, pacesetter potentials spread aborally. Spontaneous and drug-induced dysrhythmias exhibited similar characteristics. Therefore, we conclude that the origin and propagation characteristics of gastric dysrhythmias depend on the type of dysrhythmia rather than whether they are spontaneous or drug-induced.