A device, system and method for diagnosing and treating gastric disorders is provided. A functional device resides within the patient's stomach and is secured to the stomach wall by an attachment device. The functional device may be a sensor for sensing various parameters of the stomach or stomach environment, or may be a therapeutic delivery device. The functional device in one embodiment provides a device, system and method for gastric electrical stimulation where stimulating electrodes are secured to the wall of the stomach by the attachment device or otherwise. A preferred device includes: at least one stimulating electrode in electrical contact with the stomach wall; an electronics unit containing the electronic circuitry of the device; and an attachment mechanism for attaching the device to the stomach wall. The functional devices may be programmed to respond to sensed information or signals. An endoscopic delivery system delivers the functional device through the esophagus and into the stomach where it is attached the stomach wall. The endoscopic instruments attach or remove the attachment devices and functional devices from the stomach and may be used to assist in determining the optimal attachment location.

Gastric treatment and diagnosis device and method

A method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus features an implantable pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads couple to the circular layer of the stomach. The pulse generator preferably features sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions as occurring. In particular two sensors are featured. The first sensor senses low frequency gastrointestinal electrical activity between the frequency of 0.017-0.25 Hz and the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, which occurs upon normal peristaltic contractions. The second sensor only senses for a preset period after low frequency gastrointestinal electrical activity has been sensed by the first sensor. The pulse generator further delivers stimulation pulse trains to the gastrointestinal tract at a period of time after low frequency gastrointestinal electrical activity has been sensed by the first sensor. If, however, the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, then the delivery of stimulation pulse trains to the gastrointestinal tract is inhibited. In such a manner the present invention detects the occurrence of normal peristaltic contractions and further provides electrical stimulation to the gastrointestinal tract if such normal peristaltic contrations are not detected.

Method and apparatus for electrical stimulation of the gastrointestinal tract

An anticonstipation apparatus, and method, that may include using an implanted stimulus generator that may supply electrical stimuli to the muscles associated with a target portion of the patient's gut, from the esophagus to the anus, through an electrical lead and several pairs of electrodes. The electrical stimuli may be provided to nerves in the autonomic nervous system that are associated with the muscles, or the stimuli may be provided directly to the muscles themselves. The stimuli may be provided sequentially, in a proximal to caudad direction, in order to initiate, enhance or artificially produce peristalsis in the gut's target portion in a proximal to caudad direction. If the gut's target portion is in the descending colon, such stimulation may be coordinated with similar stimulation of the muscles associated with the rectum and anus. A sensor may be provided to detect when the target portion is experiencing constipation.

Apparatus and method for treating chronic constipation

Measurement of gastrointestinal motility in the GI laboratory

Using cutaneous electrodes an electrogastrographic study was made of gastric myoelectrical activity in both the fasting and postprandial states in 48 patients with unexplained nausea and vomiting and in 52 control subjects. A gastric emptying study, using a radio-labelled solid phase meal, was carried out in 30 of these 48 patients. A follow up study was done after one year. In 48% of the patients abnormal myoelectrical activity was found which was characterised by: instability of the gastric pacemaker frequency; tachygastrias in both the fasting and postprandial states; the absence of the normal amplitude increase in the postprandial electrogastrogram. This last characteristic was correlated with a delayed gastric emptying of solids. The present study shows that with electrogastrography in a heterogeneous group of patients with unexplained nausea and vomiting a subgroup can be discerned with abnormal myoelectrical activity. Our findings suggests that this abnormal myoelectrical activity is related to these symptoms.

https://gut.bmj.com/content/gutjnl/27/7/799.full.pdf

Electrogastrographic study of gastric myoelectrical activity in patients with unexplained nausea and vomiting.

The object of this study was to elucidate what is actually measured in electrogastrography. Comparison of gastric signals simultaneously recorded from serosal and cutaneous electrodes in the conscious dog led to the following findings: 1. In the absence of phasic contractile activity and electrical response activity (ERA), the cutaneous recordings contained a frequency corresponding to the fundamental frequency of the electrical control activity (ECA) of the stomach (about 0.08 Hz). 2. Tachygastrias gave rise to cutaneous signals containing the tachygastric frequency (about 0.25 Hz). 3. The amplitude of the electrogastrogram increased when ERA occurred. It is concluded that both ECA and ERA are reflected in the electrogastrogram. A model is proposed that describes the electrogastrogram as the result of field potentials generated by depolarization and repolarization dipoles.

What is measured in electrogastrography

The recording of gastric myoelectrical activity by means of cutaneous electrodes attached to the external abdominal wall is termed electrogastrography. Respiration and motion artefacts hamper the interpretation of electrogastrographic signals. Running spectrum analysis, using the fast Fourier transform, seems to provide a concise spectral representation of electrogastrographic data. In this paper the concept of running spectrum analysis is presented in detail using test signals consisting of frequency modulated sine waves and actual recordings from dog and man. Especially the visual interpretable representation in appropriate plots is emphasised and discussed. It is demonstrated that tachygastrias with a duration of the order of 30s can easily be recognised in the spectra. In most cases the gastric frequency can be recognised in the spectra. It is concluded, therefore, that running spectrum analysis has to be considered an attractive noninvasive method to study gastric myoelectrical activity in dog and man.

Running spectrum analysis as an aid in the representation and interpretation of electrogastrographic signals.

Interdigestive myoelectric activity and mechanical activity were studied simultaneously by means of cutaneous electrodes (electrogastrography) and intraluminal pressure recording, respectively, in 10 healthy male volunteers. The aims of the present study were 1) to describe the characteristics of the electrogastrogram during the different phases of the interdigestive migrating complex (IMC) in healthy subjects and 2) to determine to what extent these characteristics can be used to identify the different phases of the IMC. The electrogastrograms were analyzed visually and by running-spectrum analysis. It was concluded that in humans the gastric frequency present in the electrogastrogram appears to be less stable during motor activity than during motor quiescence, in particular during phase III, but far more stable than its canine counterpart. A small but consistent drop in gastric frequency was observed in the changeover from motor quiescence to phase II motor activity. The power of the gastric frequency increased with increasing motor activity, except during phase III. A characteristic frequency and power behavior during phase III could only be recognized in a minority of the IMCs. In general, electrogastrography cannot, given the present state of the art, be used to precisely identify the different phases of the IMC.

Electrogastrographic characteristics of interdigestive migrating complex in humans

Interdigestive gastric contraction-related phenomena were studied in four healthy conscious dogs by running-spectrum analysis of signals derived from the abdominal surface. When groups of contractions occur irregularly spaced in time, low frequencies (in the range below 0.085 Hz) show up in the power spectra of the electrogastrograms. It has been hypothesized that prolonged electrical control activity (ECA) intervals shown to coincide with irregular contractions are related in some way to these low frequencies. This hypothesis was investigated in detail. Whereas a certain degree of correlation was demonstrated between ECA interval variations, contractile activity, and the presence of low frequencies in the spectra obtained from electrogastrograms recorded during interdigestive migrating complexes, a more pronounced correlation between these phenomena was found during "minute rhythms." It was concluded that the presence of lower frequencies ranging from the normal gastric one to about 0.01 Hz in the running-spectrum representation of electrogastrograms recorded in fasting dogs is indicative of strong antral contractions and that the mechanism through which this is brought about involves prolongation of ECA intervals associated with these contractions.

J. L. Grashuis

Papers

What is measured in electrogastrography

Electrogastrographic study of gastric myoelectrical activity in patients with unexplained nausea and vomiting.

Running spectrum analysis as an aid in the representation and interpretation of electrogastrographic signals.

Electrogastrographic characteristics of interdigestive migrating complex in humans

Contraction-related, low-frequency components in canine electrogastrographic signals