Electrogastrography: physiological basis and clinical application in diabetic gastropathy

Electrogastrography is the recording and measurement of gastric myoelectrical activity from electrodes placed on the surface of the epigastrium. Normal electrogastrograms (EGGs) reflect 3 cycles per min (cpm) gastric myoelectrical activity produced by specialized pacemaker cells, the interstitial cells of Cajal, located in the muscular wall of the gastric corpus and antrum. Gastric dysrhythmias (tachygastrias and bradygastrias) are disturbances of the normal gastric pacesetter potentials and are associated with symptoms of nausea, epigastric fullness, and bloating and with hyperglycemia and delayed gastric emptying. In diabetic gastropathy, the normal 3-cpm electrical rhythm is replaced with bradygastrias, tachygastrias, and mixed or nonspecific dysrhythmias. Diagnosis of gastric dysrhythmias identifies an objective neuromuscular abnormality in diabetic patients with upper gastrointestinal (GI) symptoms. Correction of gastric dysrhythmias decreases upper GI symptoms and may improve gastric emptying all of which may enhance glucose control. The EGG diagnosis of gastric dysrhythmias provides new insights into gastric neuromuscular abnormalities and guides therapies to improve upper GI symptoms in patients with diabetes mellitus.     

Electrogastrography in patients with Roux-en-Y reconstruction after previous Billroth gastrectomy

BACKGROUND/AIMS: The aim of this prospective study was to characterize gastric myoelectrical activity in patients with Roux-en-Y reconstruction after previous Billroth gastrectomy. METHODOLOGY: Thirteen patients entered the study (6 men and 7 women, aged 35-57). The mean time from Roux-en-Y reconstruction to electrogastrography (EGG) recording was 5 years. Surface cutaneous EGG was recorded using a Digitrapper EGG in the morning both fasting and after a standard solid test meal. All patients assessed their dyspeptic symptoms at the time of EGG in a semi-quantitative subjective scale. RESULTS: EGG was abnormal in all studied patients (but one postprandial recording). Dyspepsia was not meal-related and was not more severe in Helicobacter pylori positive patients. There was a significant negative correlation between time from Roux-en-Y reconstruction to EGG recording and bradygastria percent activity, both fasted and postprandial (r = -0.576; p = 0.0022). There was an inverse trend between severity of dyspepsia and normal slow-wave rhythm percent activity. Older patients tended to have more severe dyspepsia. CONCLUSIONS: The results of this study suggest that abnormal EGG recording is associated with dyspepsia in patients after Roux-en-Y reconstruction.     

Gastric myoelectrical activity and gastric emptying in patients with functional dyspepsia

OBJECTIVES: The aims of this study were to investigate gastric myoelectrical activity and gastric emptying (GE) and their relationship in patients with functional dyspepsia. METHODS: The study was conducted in 15 healthy volunteers (six women, nine men, mean age: 42 yr) and 15 patients (13 women, two men, mean age: 43 yr) with functional dyspepsia. Gastric myoelectrical activity was recorded using cutaneous electrogastrography (EGG) for 30 min in the fasting state and for 120 min simultaneously with GE monitoring after an isotope-labeled solid meal. The anterior/posterior images of the stomach were taken using a technetium scanner immediately after eating, and then at 1, 2, and 4 h to determine the percentage of gastric retention. The dominant frequency of the EGG, the change of the postprandial EGG peak power (deltaP), and the percentage of normal 2-4 cycles/min (cpm) slow waves during each recording session were calculated and compared between the patients and healthy subjects. RESULTS: The patients had a significantly lower mean percentage of 2-4 cpm slow waves, both in the fed state and in the fasting state, than did healthy subjects. Compared to the EGG in the fasting state, a significant increase of the EGG dominant frequency in the fed state was observed in healthy subjects but not in the patients. The mean postprandial EGG power increase in the patients was substantially less than in the healthy subjects during the first postprandial hour but similar during the second postprandial hour. The mean percentage of gastric retention in patients is substantially higher than in the healthy subjects, both at 2 h after eating and at 4 h after eating. Of 15 patients, nine (60%) had delayed GE (gastric retention at 2 h >50%) and 10 (66%) had abnormal EGGs (percentage of 2-4 cpm <70% and/or deltaP < 0). Eight of these 10 patients (80%) with abnormal EGGs had delayed GE. CONCLUSIONS: A high proportion of adult patients (60%) with functional dyspepsia have abnormally slow GE and abnormalities in gastric myoelectrical activity.     

Inhibitory effects of cholecystokinin on postprandial gastric myoelectrical activity

While a number of studies have investigated the effects of cholecystokinin (CCK) on gastrointestinal motility, little is known on the effects of CCK on gastric myoelectrical activity, which regulates gastric motility. The aim of this study was to investigate the effects of intravenous infusion of CCK-8 on gastric myoelectrical activity in normal humans. Gastric myoelectrical activity was measured in 10 healthy subjects with a noninvasive electrogastrographic technique by placing abdominal electrodes on the epigastric area. Two study sessions were performed in each subject on two separate days with double-blinded infusion of either saline or CCK (24 pmol/kg/hr). The procedure for each session was as follows: (A) 30-min baseline fasting electrogastrogram (EGG); (B) start infusion, another 30-min EGG; (C) give meal, 60-min EGG; and (D) stop infusion, another 60-min EGG. The dominant frequency and peak power (amplitude) of the EGG, and the percentage of normal 2–4 cycles/min slow waves during each recording session were computed and compared between placebo and CCK. It was found that normal 3 cpm slow waves were recorded in all EGGs. Infusion of CCK had no effect on the frequency of the gastric slow wave and did not induce gastric dysrhythmias. It was also found that intravenous infusion of CCK significantly decreased the EGG peak power (amplitude) during the first hour after the meal (the infusion was given during this period) in comparison with placebo (P<0.05). This inhibitory effect on EGG peak power was sustained but not significant during the second postprandial hour (the infusion was not given during this period). It was concluded that intravenous infusion of CCK at a physiological concentration significantly decreased the postprandial EGG amplitude in normal humans, suggesting an inhibitory effect on postprandial gastric motility, but did not change the frequency and regularity of the gastric slow wave.     

Gastric Myoelectrical Activity in the First Trimester of Pregnancy: A Cutaneous Electrogastrographic Study

Recently, it has been shown that changes in gastric electrical rhythm can be connected with clinical syndromes characterized by nausea and vomiting, among these the nausea of pregnancy. We studied gastric electrical activity during the first trimester of pregnancy in nine women with nausea and vomiting (study group) by means of cutaneous electrogastrography. Recordings were made before and after a standardized meal in the 6th-8th wk of gestation, and 2 months after voluntary interruption of pregnancy (VIP). The control group consisted of eight pregnant women without a history of nausea and vomiting. In the women in the study group there was more unstable cutaneous electrogastrographic (EGGc) activity and a reduced increase in postprandial power during pregnancy than after VIP, when a normal pattern with regular 3-cpm EGGc waves was reestablished. The coefficient of variation of gastric frequency during pregnancy was significantly higher than after VIP (p less than 0.01), whereas the postprandial to preprandial power ratio was lower (p less than 0.01). During the recording sessions, none of the subjects had clear episodes of tachygastria or bradygastria, and none of them had nausea, vomiting, or epigastric discomfort. Comparison of the EGGc data for the pregnant women in the study and control groups revealed a similar pattern of gastric electrical activity in the two, the only exception being the power ratio, which was lower in the study group (p less than 0.01). We conclude that pregnant women without symptoms of nausea and vomiting at the time of EGG recordings have normal 3-cpm myoelectrical activity, and that EGGc activity is more unstable and less responsive to the ingestion of food during pregnancy than after VIP. Furthermore, in pregnant women with a history of nausea and vomiting, EGGc activity is less responsive to the ingestion of food than it is in symptom-free pregnant women.     

Delayed gastric emptying in patients with diffuse versus limited systemic sclerosis, unrelated to gastrointestinal symptoms and myoelectric gastric activity

OBJECTIVE: To study the gastric function in patients with diffuse and limited systemic sclerosis (SSc) in relation to the degree of upper gastrointestinal symptoms. METHODS: Scintigraphic gastric emptying and recording of the myoelectric signals of the stomach were examined in 15 patients with diffuse SSc (dSSc), 13 patients with limited SSc (lSSc) and 15 healthy controls. The frequency of upper gastrointestinal symptoms was determined using a questionnaire. RESULTS: Patients with dSSc had slower gastric emptying (scintigraphic gastric half-emptying time median (Md) 103 min, range 75-447 min) than control subjects (Md 70 min, range 38-94) and patients with lSSc (Md 76 min, range 43-460). Electrogastrographic recordings did not differ between dSSc, lSSc or controls. Symptoms tended to be more abundant in dSSc patients than in lSSc patients, however, patients with a high frequency of symptoms did not differ from patients with low frequency of symptoms in gastric function, as measured with scintigraphic gastric emptying or electrogastrography (EGG). Neither EGG nor a thorough review of upper gastrointestinal symptoms could predict delayed gastric emptying. CONCLUSION: The higher prevalence of delayed gastric emptying in patients with dSSc in this study indicates a more severe involvement of the gastrointestinal tract in dSSc than in lSSc, and stresses the importance of differentiating between the subtypes of SSc patients. Since EGG dysrythmia did not correlate with gastric emptying we concluded that factors other than defective myoelectric signals might contribute to a disturbed gastric function.     

Myo-electrical and motor activity of the stomach in the first days after abdominal surgery: Evaluation by electrogastrography and impedance gastrography

The electrical and motor activities of the stomach were studied in the early postoperative phase after abdominal surgery by means of surface recording techniques: electrogastrography (EGG) and impedance gastrography (IGG). EGG and IGG recordings were made pre-operatively and on the first and second postoperative days. Physical signs and symptoms related to gastrointestinal motility were assessed. Two patient groups were studied; a group of patients undergoing cholecystectomy (n = 9) was compared with a group with major colonic surgery (n = 14). After colonic surgery, resumption of a normal oral diet was later and nausea and vomiting were seen more frequently than after cholecystectomy. Other physical signs concerning intestinal motility did not differ between the groups. Gastric myo-electrical activity (0.04-0.06 Hz), recorded electrogastrographically, tended to decrease in the postoperative phase in both groups, and return to pre-operative values later in the colonic surgery group. However, none of the differences reached statistical significance. Abnormal gastric activity (tachyarrhythmia) was observed in one pre-operative patient but in 6 patients (2 cholecystectomy, 4 colonic surgery) after operation. IGG variables were not significantly affected by the operation and were not significantly different between the groups. No correlation between the symptoms nausea and vomiting in the postoperative phase and the incidence of tachyarrhythmias could be demonstrated in this study. It is concluded that antral myo-electrical and motor activity, measured with non-invasive techniques (EGG and IGG), are not grossly abnormal on the first and second postoperative day after abdominal surgery. It is further concluded that abnormal gastric frequencies do not appear to play a major role in the genesis of postoperative nausea and vomiting.     

Utility of electrogastrography in differentiating Parkinson's disease with or without gastrointestinal symptoms: a prospective controlled study

BACKGROUND/AIMS: Parkinson's disease (PD) may be associated with various gastrointestinal symptoms. This study was designed to assess the gastric myoelectrical functioning in patients with PD and in healthy controls by using electrogastrography (EGG) with the water load test and to determine the clinical utility of EGG in differentiating PD patients with or without upper gastrointestinal symptoms. METHODS: Twenty patients (13 men, mean age 63 years) with PD and 11 healthy controls (5 men, mean age 55 years) were studied. The PD patients were stratified into two subgroups: 9 were assessed as PD without upper gastrointestinal symptoms (group A) and 11 as PD with upper gastrointestinal symptoms (group B). The gastric myoelectrical activity was assessed using cutaneous electrodes to record EGG before and after the subjects ingested water until full. RESULTS: The PD patients drank significantly less water until full as compared with the controls (303 +/- 45 vs. 627 +/- 67 ml, p < 0.05). At baseline, the PD patients had a significantly higher 1.0- to 2.5-cpm activity as compared with the controls (44 +/- 3 vs. 33 +/- 3%, p < 0.05). These differences persisted after ingestion of the water load. The PD patients had a significantly lower 2.5- to 3.75-cpm activity late after ingestion of the water load as compared with the controls (33 +/- 4 vs. 49 +/- 5%, p < 0.05). No statistically significant differences were found in any EGG variables or the water load between the two groups of PD patients. CONCLUSIONS: This study has shown that the gastric myoelectrical activity is impaired in both groups of PD patients. EGG appears to have a limited, if any, clinical utility in the differentiation of PD patients with or without upper gastrointestinal symptoms.     

Electrogastrography Before and After a High-Caloric,Liquid Test Meal in Healthy Volunteers and Patients with Severe Functional Dyspepsia

Background: The cutaneous recording of gastric electric rhythm, so-called electrogastrography (EGG), has been purported as a non-invasive method for studying patients with functional dyspepsia and unexplained nausea and vomiting. The aims of this study were to determine normal values for EGG characteristics before and after a liquid, high-caloric test meal and to investigate whether EGG could discriminate between patients with functional dyspepsia and normal controls. Methods: In studying 20 healthy volunteers and 10 patients with functional dyspepsia, we recorded gastric electrical activity during the 30 min before and after a liquid 1.0-1.5 kcal/ml test meal. Satiety before and after the meal was estimated on a 10-point scale. EGG was analysed regarding dominant frequency, instability of the dominant frequency, power ratio and percentage activity in the normal frequency range. Results: The mean ( ± s ) caloric intake in patients with functional dyspepsia (286 ± 160 kcal) was significantly lower ( P < 0.001) than in healthy volunteers (610 ± 211 kcal). The patients reported a more pronounced feeling of satiety before the test meal (5.6 ± 3.2) compared to healthy volunteers (3.6 ± 1.2, P < 0.05), but at the end of the test meal there was no difference in satiety (7.9 ± 2.5 versus 7.7 ± 1.0). However, none of the EGG parameters showed any difference between patients and healthy volunteers. Conclusions: EGG before and after a high-caloric test meal showed large variation in healthy subjects and seemed to be of little value for differentiating between healthy individuals and patients with functional dyspepsia.     

Gastric involvement in systemic sclerosis: a prospective study

OBJECTIVES: This study aims to assess the prevalence of gastric electrical activity dysfunction with cutaneous electrogastrography (EGG), disturbances of gastric emptying function using radiopaque pellets, and gastric endoscopic abnormalities in patients with systemic sclerosis (SSc). We also investigate for an association between EGG and gastric-emptying data with clinical manifestations and esophageal motor disturbances. METHODS: Fasting and postprandial gastric electrical activity was studied in 22 consecutive patients with SSc (17 with and 5 without clinical gastric manifestations) and 22 age- and sex-matched healthy subjects. Gastric emptying of radiopaque pellets and gastroscopy were also performed in SSc patients. RESULTS: The prevalence of EGG disturbances was as high as 81.82% in SSc patients. SSc patients exhibited, compared with controls, higher median percentage of dominant frequency in bradygastria during the fasting period and lower median values for postprandial electrical power and postprandial to fasting ratio for electrical power. Gastric emptying of radiopaque pellets was delayed in 11 SSc patients, and gastroscopy demonstrated "watermelon stomach" in 3 SSc patients. No correlation was found between the severity of gastric impairment and clinical presentation, SSc duration and subsets, and esophageal manometric impairment. CONCLUSIONS: Our study underlines the high frequency of gastric dysfunction in SSc patients. It suggests the usefulness of EGG in SSc in noninvasively detecting disorders of gastric electrical activity at an early stage and symptomatic patients with gastroparesis (because there was a correlation between values of postprandial to fasting ratio for electrical power of < 1 on EGG and delayed gastric emptying). Gastric-emptying evaluation of radiopaque pellets may further be a helpful method to depict symptomatic SSc patients with gastroparesis. Finally, our series confirms that watermelon stomach diagnosis should be excluded in SSc patients presenting with gastrointestinal hemorrhage or with anemia related to iron deficiency.     

Electrogastrography before and after a high-caloric,liquid test meal in healthy volunteers and patients with severe functional dyspepsia

BACKGROUND: The cutaneous recording of gastric electric rhythm, so-called electrogastrography (EGG), has been purported as a non-invasive method for studying patients with functional dyspepsia and unexplained nausea and vomiting. The aims of this study were to determine normal values for EGG characteristics before and after a liquid, high-caloric test meal and to investigate whether EGG could discriminate between patients with functional dyspepsia and normal controls. METHODS: In studying 20 healthy volunteers and 10 patients with functional dyspepsia, we recorded gastric electrical activity during the 30 min before and after a liquid 1.0-1.5 kcal/ml test meal. Satiety before and after the meal was estimated on a 10-point scale. EGG was analysed regarding dominant frequency, instability of the dominant frequency, power ratio and percentage activity in the normal frequency range. RESULTS: The mean (+/-s) caloric intake in patients with functional dyspepsia (286 +/- 160 kcal) was significantly lower (P < 0.001) than in healthy volunteers (610 +/- 211 kcal). The patients reported a more pronounced feeling of satiety before the test meal (5.6 +/- 3.2) compared to healthy volunteers (3.6 +/- 1.2, P < 0.05), but at the end of the test meal there was no difference in satiety (7.9 +/- 2.5 versus 7.7 +/- 1.0). However, none of the EGG parameters showed any difference between patients and healthy volunteers. CONCLUSIONS: EGG before and after a high-caloric test meal showed large variation in healthy subjects and seemed to be of little value for differentiating between healthy individuals and patients with functional dyspepsia.     

Gastric emptying and gastric myoelectrical activity in patients with diabetic gastroparesis: effect of long-term domperidone treatment

We measured gastric emptying and gastric myoelectrical activity with solid-phase gastric-emptying tests and cutaneously recorded electrogastrograms (EGGs), respectively, in six insulin-dependent diabetic patients with nausea and vomiting who did not respond to standard treatments. Baseline solid phase gastric emptying was markedly delayed (78 +/- 8% retained at 120 min) and EGG recordings revealed gastric dysrhythmias; tachygastria (4-9 cpm signals) in one patient, 1- to 2-cpm waves in two patients, and flatline patterns in three patients. No patient had a normal 3-cpm EGG pattern. After 6 months of domperidone treatment, mean upper gastrointestinal symptoms scores decreased from 17.8 to 3.7 (p less than 0.01), and normal 3-cpm EGG frequencies were recorded from each of the six patients. The mean percentage of meal retained at 120 min decreased but did not improve significantly. Thus, establishment of normal 3-cpm gastric myoelectric activity and resolution of dysrhythmias, not normalization of emptying rates, was associated with improvement in upper gastrointestinal symptoms in these diabetic patients.     

Edrophonium Provocative Testing During Electrogastrography (EGG) (Effects on Dyspeptic Symptoms and the EGG)

The aim of this study was to determine whetheredrophonium induces dyspeptic symptoms and/or gastricmyoelectric changes in normal subjects and patients withfunctional dyspepsia. Eighteen normal controls and 28 patients with functional dyspepsiaunderwent electrogastrography (EGG) with edrophoniumadministration. After EGG recording with 1-hr fastingand 2-hr postprandial periods, subjects received anintravenous infusion of saline (placebo) followed byedrophonium 10 mg. After each injection, the EGG wasrecorded for 15 min and symptoms scored. Patients withfunctional dyspepsia had significantly more frequent gastrointestinal symptoms in response toedrophonium than normal controls. Edrophonium had noeffect on EGG dominant frequency, but increased thepower of the dominant frequency in both controls anddyspeptic patients. In the dyspeptic patients,reproduction of the patient's symptoms was associatedwith an increase in the power of the dominant frequency,whereas when no symptoms were produced, there was nochange in power. Overall, 21 of 28 dyspeptic patients(75%) had either an abnormal baseline EGG (N = 10) or anormal EGG and positive edrophonium test (N = 11). Inconclusion, edrophonium administration can reproduce symptoms in some dyspeptic patients.Symptoms after edrophonium administration may be relatedto either more vigorous gastric contractions and/orincreased visceral perception of normal gastric contractions.     

Electrogastrography: possibilities and limits

A cutaneous electrogastrogram (EGG) is a recording of the electrical activity of the stomach by means of electrodes placed on the abdominal skin surface. Recently, there has been an increased interest in the cutaneous EGG due to the development of new recording techniques and improved methods of signal analysis, and as a result of these developments recent studies have been able to demonstrate that alterations in gastric electrical activity may be accompanied by unexplained nausea and vomiting. In spite of the diagnostic potential of the cutaneous EGG, there are numerous problems which must be resolved before widespread clinical use is possible. The authors review the current status of the cutaneous EGG and describe their own experience of its use in the study of certain organic gastric diseases.     

Effect of laparoscopic Nissen fundoplication on symptoms and gastric myoelectric activity in gastroesophageal reflux disease

BACKGROUND: Laparoscopic Nissen fundoplication is an effective treatment for gastroesophageal reflux disease (GERD). The aim of this study was to determine whether laparoscopic fundoplication alters gastric myoelectric activity. Change of digestive symptoms was also assessed. METHODS: Sixteen patients with GERD (2 males, 14 females, mean age: 53 years) undergoing a laparoscopic fundoplication participated. Electrogastrography (EGG) was assessed before and after the subject ingested water until full (water load). Symptoms of upper abdominal discomfort, early satiety, postprandial abdominal distension, nausea, vomiting, and anorexia were recorded. At a 2-month postoperative follow-up, preoperative tests were repeated. RESULTS: The EGG was abnormal in 11 of 16 patients (69%) preoperatively and 6 of 16 patients (38%) postoperatively. The EGG changed from abnormal to normal in 5 of 16 patients (31%). The percentage of power at 3 cpm increased significantly during the fasting state postoperatively (29.9% vs. 21.2%, P < 0.05). There was a significant improvement in epigastric pain (P < 0.001), early satiety (P < 0.01), and postprandial fullness (P < 0.001). CONCLUSIONS: Increased presence of normal 3 cpm activity is the predominant effect of fundoplication on gastric myoelectric activity. Dyspeptic symptoms are also significantly improved postoperatively.     

Gastric electrical dysrhythmia following cholecystectomy in humans.

In order to observe the incidence of dysrhythmia in 20 patients who had undergone cholecystectomy, we recorded gastric electrical activity by means of serosal electrodes from the day of surgery to the 6th postoperative day. The difference between the incidence of dysrhythmia on the day of the operation and the other days is statistically significant (t test: p less than 0.001). Bradygastria was the most frequently observed dysrhythmia, both on the day of surgery and on the following days. It had a frequency of around 1.0-1.5 cpm and the episodes lasted for a minimum of 10 min to a maximum of 105 min (mean duration 32.6 min). Episodes of tachygastria were of varying duration, ranging from a minimum of 3 min to a maximum of 60 min (mean duration 18.5 min), whereas episodes of gastric tachyarrhythmia lasted between 2 min and 21 min (mean duration 5.4 min). Only 1 patient had an episode of nausea and biliary vomiting, associated with an episode of gastric tachyarrhythmia on the 1st postoperative day. None of the other patients had symptoms of impaired gastric function, such as nausea, vomiting, bloating and epigastric pain, at any time during the recording sessions. These findings suggest that in most cases, gastric electrical rhythm returns to normal within 24 h of cholecystectomy and further that gastric dysrhythmia is not related to symptoms of impaired gastric function. The etiological mechanism and clinical significance of gastric dysrhythmia, therefore, are still unclear.     

Electrogastrography: basic knowledge, recording, processing and its clinical applications

The slow wave (SW) of the gastrointestinal (GI) tract mainly functions to trigger the onset of spike to elicit smooth muscle contraction, which provides the essential power of motility. Smooth muscle myogenic control activity or SW is believed to originate in the interstitial cells of Cajal (ICC). The electrical coupling promotes interaction between muscle cells, and ICC additionally contribute to SW rhythmicity. Stomach SW originates in the proximal body showing the continuous rhythmic change in the membrane potential and propagates normally to the distal antrum with a regular rhythm of approximately 3 c.p.m. A technique using electrodes positioned on the abdominal skin to pick up stomach rhythmic SW refers to electrogastrography (EGG). The stomach SW amplitude is very weak, while many visceral organs also produce rhythmic electricities, for example heartbeat, respiration, other organs of the GI tract and even body movements. Thus noise other than SW should be filtered out during the recording, while motion artifacts are visually examined and deleted. Finally, the best signal among all recordings is selected to compute EGG parameters based on spectral analysis. The latter is done not only to tranform frequency domain to time domain but also to provide information of time variability in frequency. Obtained EGG parameters include dominant frequency/power, % normal rhythm, % bradygastria, % tachygastria, instability coefficient and power ratio. Clinical experience in EGG has been markedly accumulated since its rapid evolution. In contrast, lack of standardized methodology in terms of electrode positions, recording periods, test meals, analytic software and normal reference values makes the significance of EGG recording controversial. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Understanding basic SW physiology, recording methodology and indications may open EGG as a new domain to approach the stomach motor dysfunction.     

Gastric electrical activity in patients with cholelithiasis undergoing laparoscopic cholecystectomy: a prospective controlled study

BACKGROUND: The aim of the present study was to evaluate the effect of gallstone disease (GD) and laparoscopic cholecystectomy on gastric electrical activity of slow waves, which was recorded via transcutaneous electrogastrography (EGG). METHODS: Twenty-one consecutive patients (M/F: 12/9, 52.7 +/- 15 years old) with GD and no previous history of abdominal operations or known disease affecting gastrointestinal motility were studied. The EGG was performed for 30 min prior to and 90 min after a standard meal, during a 4-6 month period prior to and after laparoscopic cholecystectomy. The percentile proportion of the three spectra of gastric slow waves frequency was studied, defined as follows: bradygastria, 1-2.1 cycles per min (c.p.m.); normogastria, 2.2-3.9 c.p.m.; and tachygastria, 4-9 c.p.m. The findings were compared to those of nine healthy subjects (M/F: 5/4, 49.5 +/- 14.8 years old). RESULTS: No statistically significant difference was found in percentile distribution of bradygastria, normogastria and tachygastria, pre- or post-prandially, neither before or after laparoscopic cholecystectomy, nor between patients and controls. CONCLUSIONS: Patients with GD do not exhibit differences in gastric electrical activity of slow waves in comparison to normal subjects and laparoscopic cholecystectomy does not alter gastric electrical activity. These findings suggest that cholelithiasis does not seem to cause dyspeptic symptoms due to gastric dysrythmias.     

Evolution of gastric electrical features and gastric emptying in children with Duchenne and Becker muscular dystrophy

OBJECTIVES: Although muscular dystrophy (MD) affects primarily striated muscles, smooth muscle cells of the gastrointestinal tract may also be involved. We recorded gastric electrical activity and gastric emptying time (GET) in children with MD at initial presentation and at 3-yr follow-up in order to detect gastric motor abnormalities and study their evolution along the clinical course. METHODS: Twenty children with MD (median age: 4.6 yr; range age: 3-7 yr) were investigated by means of ultrasonography, for measuring GET, and by electrogastrography (EGG); 70 children served as controls. RESULTS: Ten patients had Duchenne muscular dystrophy (DMD) and 10 Becker muscular dystrophy (BMD). GET was significantly more delayed in MD patients (DMD, median: 195 min; range 150-260 min; BMD, median: 197 min; range: 150-250 min) than in controls (median: 150 min; 110-180 min; p < 0.05); it markedly worsened at the follow-up in DMD (median: 270 min; range 170-310 min; p < 0.001 vs controls) but not in BMD patients (median: 205 min; 155-275 min; p < 0.05 vs DMD). Baseline EGG showed a significantly lower prevalence of normal rhythm and significantly higher prevalence of dysrhythmias in both groups of patients as compared to controls (% of normal rhythm: DMD 66.7 +/- 8.2, BMB 67.2 +/- 11.5, controls 85.3 +/- 7.2, p < 0.001; % of tachygastria: DMD 28.4 +/- 8.0, BMB 29.8 +/- 12.3, controls 10.6 +/- 5.1, p < 0.001; % of dominant frequency instability coefficient: DMD 36.1 +/- 6.0, BMB 33.2 +/- 2.9, controls 17.9 +/- 7.1, p < 0.001); furthermore, no difference in fed-to-fasting ratio of the dominant EGG power was found between the two groups and controls (DMD 2.84 +/- 1.27, BMB 2.82 +/- 0.98, controls 3.04 +/- 0.85, ns). However, at the follow-up no significant change in the prevalence of normal rhythm and dysrhythmias occurred in both groups (ns vs baseline values), whereas only DMD patients showed a marked reduction in fed-to-fasting power ratio (0.78 +/- 0.59; p < 0.001 vs controls and BMD; p < 0.05 vs baseline), which correlated with the progressive neuromuscular weakness occurring in DMD subjects (r, 0.75; p < 0.001). CONCLUSIONS: In children with MD, there is an early abnormality in gastric motility that is due to deranged regulatory mechanisms, whereas contractile activity of smooth muscle cells seems to be preserved. At the follow-up, DMD patients exhibited a progressive failure in neuromuscular function, which was accompanied by a gastric motility derangement with worsening in GET and in EGG features suggesting an altered function of gastric smooth muscle cells.     

Trans-cutaneous electrogastrographic study of gastric myoelectric activity in transposed intrathoracic stomach after esophagectomy

We examined the feasibility of trans-cutaneous electrogastrography (EGG) in recording myoelectric activity of the transposed thoracic stomach after esophagectomy. Nineteen patients who had Ivor-Lewis esophagectomy were studied. The EGG signal was recorded using cutaneous electrodes placed over the lower sternum. Eleven patients who underwent total gastrectomy served as controls. Normal rhythm pattern (2.4-3.6 cpm > or = 70%) and power ratio (PR > or = 2) was observed in five and 12 patients, respectively, after esophagectomy. The observation of normal gastric rhythm was more frequent in the postprandial period in the esophagectomy group (median 42.6%vs. 7.4%, P = 0.01), and the PR was significantly higher (median 2.27 vs. 1.38, P = 0.013) than the gastrectomy group. Feeding further increased the prevalence of normal gastric slow wave in the esophagectomy group (median 14.8% to 42.6%, P = 0.002) and improved the stability of dominant frequency (median 78% to 67%, P = 0.015). We conclude that gastric myoelectric activities of thoracic transposed stomach can be detected from cutaneous sternal electrodes. This represented a preservation of gastric motility even when the stomach is pulled up to the thorax as a substitute for the esophagus.