Multichannel Electrogastrography Research Articles

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects

Functional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin–electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly identify the gastric slow wave (SW) main components by applying multivariate variational mode decomposition (MVMD) to the multichannel EGG. Another aim was to obtain the 2D SW vectorgastrogram VGGSW from 4 electrodes perpendicularly arranged in a T-shape and analyse its dynamic trajectory and recurrence quantification (RQA) to assess slow wave vector movement in healthy subjects. The results revealed that MVMD can reliably identify the gastric SW, with detection rates over 91% in fasting postprandial subjects and a frequency instability of less than 5.3%, statistically increasing its amplitude and frequency after ingestion. The VGGSW dynamic trajectory showed a statistically higher predominance of vertical displacement after ingestion. RQA metrics (recurrence ratio, average length, entropy, and trapping time) showed a postprandial statistical increase, suggesting that gastric SW became more intense and coordinated with a less complex VGGSW and higher periodicity. The results support the VGGSW as a simple technique that can provide relevant information on the “global” spatial pattern of gastric slow wave propagation that could help diagnose gastric pathologies.

Gastric Myoelectric Activity and Body Composition Changes during Weight Loss via Sleeve Gastrectomy and Lifestyle Modification: Prospective Cohort Study.

The capability of bariatric surgery (BS) and lifestyle intervention (LSI) in ameliorating obesity-associated altered gastric myoelectric activity (GMA) in relation to body composition is underinvestigated. This work studied GMA during weight loss via sleeve gastrectomy and multimodal lifestyle intervention. Seventy-nine participants with morbid obesity were assigned into three groups: bariatric surgery (BS group, n = 27), in which laparoscopic sleeve gastrectomy was performed; lifestyle intervention (LS group, n = 22), in which a calorie-deficit balanced diet with gradual physical activity and personalized behavioral modification were carried out; and waitlist control (C group, n = 30). For all participants, multichannel electrogastrography (EGG) with water-load testing and bioelectric impedance body composition analysis were done at baseline, after three months, and at six months. In the BS group, the water-load volume was decreased but without improvement in the bradygastria. In the LS group, preprandial bradygastria were reduced and some postprandial normogastria were increased throughout the study period. Except for fat-free mass and total body water, the parameters of body composition changes were superior in the BS group. In the LS group, the amount of fat-mass loss was negatively correlated with bradygastria times and positively correlated with preprandial and the early postprandial average dominant frequency (ADF). In addition, in the BS group, fat-mass loss was positively correlated with the ADF at late postprandial times. In conclusion, compared to BS, LS produced moderate normalization of GMA with the preservation of fat-free mass. The GMA changes were significantly associated with the amount of fat loss, regardless of the method of obesity management.

Association of Gastric Myoelectric Activity with Dietary Intakes, Substrate Utilization, and Energy Expenditure in Adults with Obesity.

Obesity can modulate gastric myoelectric activity (GMA); however, the relationship of GMA with nutrient intakes and substrate utilization in adults with obesity is lacking. We examined the association of dietary intakes, energy expenditure, and substrate utilization with the GMA. Participants (n = 115, 18–60 y) were divided into healthy weight (HW, n = 24), overweight (OW, n = 29), obese (OB, n = 41) and morbidly obese (MO, n = 21). Two-day multi-pass 24 h recalls were conducted. The GMA was measured by multichannel electrogastrography (EGG) with water-load (WL) testing. Resting metabolic rate (RMR) and percentages of substrate utilization were measured by indirect calorimetry. In the HW, protein intake was directly correlated with average dominant frequency (ADF) and with WL volume, while in obese participants and the MO subgroup, WL volume correlated with carbohydrate intake. In participants with obesity, ADF was positively correlated with fiber intake. In participants with obesity and the OB subgroup, RMR was positively correlated with water-load volume (r = 0.39 and 0.37, p < 0.05). The ADF showed negative correlations with percent of fat utilization and positive correlations with percent of CHO utilization in non-obese groups. However, protein utilization showed inverse correlation in all obese groups. In conclusion, these distinctive associations suggest that certain dietary compositions and dieting regimens impact GMA patterns.

Association of Long-Term Dietary Intake and Gastric Myoelectric Activity in Adults with Obesity

ObjectivesTo investigate the association of long-term dietary intakes and gastric myoelectric activity (GMA) in adults with obesity vs controls.MethodsA total of 115 adults (18–60 y); 53 controls (BMI <29.90 kg/m2) and 62 patients with obesity (BMI > 30.00 kg/m2) were studied. All were free of any gastric problems. Control and cases were subdivided according to BMI into normal-weight (NW, n = 24), overweight (OW, n = 29), obesity (OB, n = 41), and morbid obesity (MO, n = 21). The protocol has IRB approval No: 20/0908/IRB. The dietary assessment has been assessed by the 2-days multiple passes 24-h recall. Then the food processor software (ESHA, USA) was used for the dietary analysis. The multichannel electrogastrography (EEG) with water load test was used to measure the GMA in the fasting state for 10 mins, and for 30 mins after water loading (3CPM-EGG, USA). The average dominant frequency (ADF) was used for analysis.ResultsPatients with MO have larger stomachs than in the NW and OB groups. The ADF was significantly lower in the MO group compared to the OB group at 10 and 20-mins indicating a state of bradygastria. Compared to the NW group, dietary composition analysis showed significant differences in obesity groups regarding the total caloric intake, carbohydrates, protein, fats, saturated fats, and fibers. The early post-prandial ADF had a positive correlation with the total caloric, carbohydrate, fiber, and fat intakes (r = 0.32, 0.32, 0.29, 0.30, respectively, n = 53, p < 0.05) in controls. A +ve correlation between ADF-30 and protein intake (r = 0.331, p < 0.05). in contrast, the ADF of the obese group did not show any significant correlations with the total caloric intake, fat, protein, and carbohydrate intake. Interestingly, ADF showed a positive correlation with total fiber intake at different time intervals in the obesity group. (ADF-20, ADF-30, ADF-40 r = 0.33, 0.38, 0.29, respectively, n = 62, p < 0.05). In contrast ADF-20 showed −ve association with the caffeine in obesity group (r = − 0.27, n = 62, p < 0.05).ConclusionsAssociation of ADF of the GMA with dietary intakes was evident and showed a distinctive pattern in the obese and controls.Funding SourcesThis project was funded by the National Plan for Science, Technology, and Innovation (MAARIFAH), King Abdulaziz City for Science and Technology, Kingdom of Saudi Arabia, Project No: 2-17-03-001-0060.

Association of Gastric Myoelectrical Activity With Ghrelin, Gastrin, and Irisin in Adults With Metabolically Healthy and Unhealthy Obesity.

Background and Objective: Functional disturbances of gastric myoelectrical activity (GMA) might exist in obesity. However, studies on its association with the gastric hormones in obesity phenotypes are lacking. The objective was to study the association of GMA with the serum levels of key gastric hormones in different obesity phenotypes. Methods: A total of 139 adults (31.00 ± 11.12 years) were classified into different metabolic phenotypes of obesity: 1) normal weight-lean (NWL group): BMI <25 kg/m2 and the fat-mass index (FMI) ≤9.7 kg/m2 in females and ≤6.3 kg/m2 in males; 2) metabolically obese normal weight (MONW group): BMI <25 kg/m2 and FMI >9.7 kg/m2 in females and >6.3 kg/m2 in males; 3) metabolically healthy obese (MHO group): BMI ≥25 and FMI ≤9.7 kg/m2 in females and ≤6.3 kg/m2 in males; and 4) metabolically unhealthy obese (MUO group): BMI ≥25 and FMI >9.7 kg/m2 in females and >6.3 kg/m2 in males. The GMA was measured at the baseline and post-prandial state using a multichannel electrogastrography with a water load satiety test. The average power distribution by the frequency region and the average dominant frequency were used for analysis. Anthropometric measurements and bioelectric impedance analysis were performed to calculate the FMI and fat-free mass index (FFMI). Serum levels of ghrelin, gastrin, and irisin were measured by ELISA kits according to the manufacturer’s protocol. Results: Compared to the NWL group, gastrin and ghrelin levels were significantly low in the MUO participants, while irisin was significantly high. The EGG showed significantly lower baseline and 20-min normogastria frequencies in the MHO and MUO groups. In the MHO group, baseline duodenal frequency was positively correlated with the gastrin level, while normogastria times were positively associated with the irisin level and negatively associated with the ghrelin level. In the MUO group, percentages of bradygastria frequencies at 10, 20, and 30 min were positively correlated with the BMI and FFMI. This bradygastria was correlated positively with the irisin level and negatively with the ghrelin level. Conclusion: The EGG patterns might be associated with obesity-related gastric hormones in different obesity phenotypes. EGG may be a promising clinical tool in obesity assessment. The association of the EGG patterns with hormonal levels needs further investigation for potential practical uses.

Gastric Electrical Response Activity Assessment Method with Simple Multi Channel Electrogastrography

Gastric Electrical Response Activity Assessment Method with Simple Multi Channel Electrogastrography

TRANSCUTANEOUS MULTICHANNEL ELECTROGASTROGRAPHY: NORMAL PARAMETERS IN A BRAZILIAN POPULATION.

Electrogastrography (EGG) is a noninvasive technique for the assessment of gastric myoelectrical activity using electrodes placed on the abdominal surface. Changes in gastric myoelectrical activity may be associated with diseases such as gastroparesis, functional dyspepsia, nausea, and recurrent vomiting. In Brazil, no studies to date have assessed gastric myoelectrical activity using multichannel EGG in healthy individuals. To establish normal values of transcutaneous multichannel EGG in healthy Brazilian individuals. This was a prospective study including 20 healthy individuals who underwent EGG. Recording was performed during two periods: a preprandial recording was performed for 30 minutes, and a postprandial recording was performed for 30 minutes after a soft-solid meal of 400 kcal (20 grams of proteins, 60 grams of carbohydrates, and 9 grams of fat). We assessed dominant frequency (DF) parameters, %DF distribution, the instability coefficient, and the power ratio (PR). A total of 20 individuals (11 women and 9 men) with a mean age of 39.5±7.4 years were included. Mean DF (95%CI) ranged from 2.4 to 3.1 cpm in the resting phase and 2.6 to 3.2 cpm in the postprandial period. The %DF in normogastria range was >70% in all healthy individuals. We identified that only one individual did not present a positive response to the test meal, and the other 19 individuals showed a PR greater than 1. The instability coefficient did not change significantly with meal intake. Multichannel EGG may be applied in future studies to evaluate gastric motility disorders in the Brazilian population.

Gastric slow wave rhythm identification using new approach based on noise-assisted multivariate empirical mode decomposition and Hilbert-Huang transform.

Electrogastrography (EGG) is the method of cutaneous recording of the myoelectrical activity of the stomach. A multi-channel signal is recorded non-invasively by means of electrodes placed outside the epigastric area. The normal electrical rhythm of the stomach (slow wave) may become significantly disturbed due to disorders of gastrointestinal tract. Abnormally fast electrical rhythms are termed tachygastria, while abnormally slow rhythms are known as bradygastria. Because some features of biological signals may go undetected using the classical methods of signal spectral analysis, we propose a new method for EGG rhythm identification. In this study, the calculation of the basic rhythms of multi-channel EGG signals is performed by means of the noise-assisted multivariate empirical mode decomposition (NA-MEMD) and Hilbert-Huang transform (HHT), using EGG data from eight healthy subjects. The results were compared with those obtained using classical spectral analysis. The mean values of the normogastric index for preprandial and two postprandial stages were found to be 64.78±11.37%, 61.29±15.86%, and 63.80±13.24%, respectively. The obtained values of normogastric index are consistent with the normal human physiological value, which is approximately 70% for healthy subjects. This method is able to capture features of the signal which are mostly undetectable by standard EGG processing methods. The EGG dominant rhythm identification using the instantaneous normogastric, bradygastric, and tachygastric indices provides new insights into biological EGG patterns.

A Simulated Anatomically Accurate Investigation Into the Effects of Biodiversity on Electrogastrography.

Chronic gastrointestinal motility disorders present a significant problem in current clinical practice with new methods needed to perform routine screening and accurate diagnosis. Electrogastrography (EGG) is a non-invasive method that provides insight into the underlying gastric electrical activity. However, widespread adoption of this technique has been limited due to an incomplete sensitivity and specificity. Recent simulation studies have tried to address these issues by providing a theoretical framework for reliably distinguishing between gastric slow wave dysrhythmias. However, these studies have been limited to a singular dipole, torso, and the stomach representative model. In this paper, we aim to address those shortcomings by developing multiple stomach and torso models with multiple moving dipoles to investigate the influence of biodiversity on EGG. Four anatomically accurate models were developed based on a range of human CT scans. This allowed investigations into the influence of normal and dysrhythmic (gastric re-entry and ectopic pacemaker) gastric electrical activity on the resulting EGG. These investigations identified areas of significant morphological difference in EGG traces for all cases, but the accuracy of these methods were based on a well-defined normal baseline. The results also suggested that the areas identified varied significantly as a result of biodiversity. These findings indicate that high-resolution multichannel EGG methodologies are required to reliably account for anatomical biodiversity.

Assessment of slow wave propagation in multichannel electrogastrography by using noise-assisted multivariate empirical mode decomposition and cross-covariance analysis

Electrogastrography (EGG) is a noninvasive technique for recording the myoelectrical activity of the stomach. An electrogastrographic signal recorded by using a four-channel system with electrodes placed on the surface of the skin is a mixture of a low-frequency gastric pacesetter potential known as a slow wave, electrical activity from other organs, and random noise. The aim of this work was to investigate the possibility of detecting the propagation of the gastric slow wave from multichannel EGG data. Noise-assisted multivariate empirical mode decomposition (NA-MEMD) and cross-covariance analysis (CCA) are proposed as new detection tools. NA-MEMD was applied to attenuate the noise and extract the EGG signal from four channels, while CCA was performed to assess the time shift between the EGG signal channels. Validation of the method was performed using synthetic EGG signals and the methodology was tested on four young, healthy adults. After validation, the proposed method was applied for two kinds of human EGG data: 10-min (short) EGG data from the preprandial phase and 90–120-min (long) EGG data from the preprandial phase as well as the postprandial phase. The results obtained for both synthetic and human EGG data confirm that the proposed method could be a useful tool for assessing the propagation of slow waves. The time shift calculation from the preprandial phase of the EGG examination yielded more consistent results than the postprandial phase. The mean value of the slow wave time lag between neighbouring channels for synthetic data was found to be 4.99±0.47 s. In addition, it was confirmed that the proposed method, that is, NA-MEMD and CCA together, are robust to noise.

The Use of Continuous Wavelet Transform Based on the Fast Fourier Transform in the Analysis of Multi-channel Electrogastrography Recordings.

This paper presents the analysis of multi-channel electrogastrographic (EGG) signals using the continuous wavelet transform based on the fast Fourier transform (CWTFT). The EGG analysis was based on the determination of the several signal parameters such as dominant frequency (DF), dominant power (DP) and index of normogastria (NI). The use of continuous wavelet transform (CWT) allows for better visible localization of the frequency components in the analyzed signals, than commonly used short-time Fourier transform (STFT). Such an analysis is possible by means of a variable width window, which corresponds to the scale time of observation (analysis). Wavelet analysis allows using long time windows when we need more precise low-frequency information, and shorter when we need high frequency information. Since the classic CWT transform requires considerable computing power and time, especially while applying it to the analysis of long signals, the authors used the CWT analysis based on the fast Fourier transform (FFT). The CWT was obtained using properties of the circular convolution to improve the speed of calculation. This method allows to obtain results for relatively long records of EGG in a fairly short time, much faster than using the classical methods based on running spectrum analysis (RSA). In this study authors indicate the possibility of a parametric analysis of EGG signals using continuous wavelet transform which is the completely new solution. The results obtained with the described method are shown in the example of an analysis of four-channel EGG recordings, performed for a non-caloric meal.

Current status of multichannel electrogastrography and examples of its use

Electrogastrography (EGG) is a non-invasive diagnostic motility for recording gastric myoelectrical activity. Gastric myoelectrical activity was first recorded in 1922. Advances in recording equipment enabled widespread use of cutaneous EGG after 1985. Later, introduction of multichannel EGG (M-EGG) enabled measurement of electrical activity transmission. At present, M-EGG findings are used as objective indicators of gastric motility disorders caused by various diseases. EGG measures two categories of gastric electrical activity: electrical response activity, or spike potentials; and electrical control activity, or slow waves. The appearance of abnormal rhythmic electrical activity is indicative of abnormalities in gastric motility. The normal frequency range of gastric electrical activity (normogastria) is around 3 cycles per min. Multiple EGG parameters assist in the assessment of gastric myoelectrical activity, and significant correlations between EGG and other gastric motility tests have been demonstrated in many studies. In Japan, however, EGG remains in the exploratory stage, and its clinical use is limited. There are large variations in procedures and systems used in previous studies, thus there is a need for standardization of EGG procedures and technical terminology. Here, we outline the current status of EGG and report the M-EGG procedures used in our department in addition to our M-EGG findings.The abstract of this manuscript was presented during an educational seminar titled "Current status of gastrointestinal motility tests and keys for immediate implementation" at the 54th Annual Meeting of the Japan Society of Smooth Muscle Research

Evaluation of electrical activity after vagus nerve-preserving distal gastrectomy using multichannel electrogastrography.

BackgroundMultichannel electrogastrography (M-EGG) can be used to evaluate gastrointestinal motility. The myoelectric activity of the remnant stomach after surgery has not been measured by M-EGG. This study examined whether myoelectric activity varied with surgical technique and compared vagus nerve-preserving distal gastrectomy (VP-DG) with standard distal gastrectomy without vagus nerve preservation (DG). Furthermore, we examined the relationship between the M-EGG findings and patients' postoperative symptoms.MethodsTwenty-six patients who underwent VP-DG, 20 who underwent DG, and 12 healthy volunteers as controls were examined with M-EGG. The Gastrointestinal Symptom Rating Scale (GSRS) was used to assess postoperative symptoms.ResultsLonger periods of normal gastric function (normogastria, 2.0–4.0 cycle min–1) were detected in channel 1 in the VP-DG group than in the DG group in either the fasted or fed state (P<0.05). The percentage of slow wave coupling (%SWC) in the fed state correlated negatively with GSRS scores (reflux, r=–0.59, P=0.02; abdominal pain, r=–0.51, P=0.04, indigestion, r=–0.59, P=0.02 and total score, r=–0.75, P=0.02).ConclusionsSlow waves can be recorded non-invasively using M-EGG in the remnant stomach following gastrectomy. The VP-DG group showed better preserved gastric myoelectric activity than the DG group, and the %SWC showed a significant negative correlation with scores of GSRS (reflux, abdominal pain, indigestion and total score) in the VP-DG group.

Local differences in electrogastrographic responses to the stress of the mirror drawing test (MDT) as determined by multichannel electrogastrography

Electrogastrograms (EGGs) were recorded in human subjects (n=58) at 16 locations on the thoraco-abdominal surface before (at rest) and during the stress of the mirror drawing test (MDT) and after having a test meal. The power amplitude ratios and power content ratios of MDT to rest (MDT/rest) and postprandial state to rest (PPR/rest) were compared between gastric channels 5 and 8, and the infraumbilical channels 12, 13, 14, 15, and 16. Generally, the ratio of the 3-cpm group in channels 5 and 8 was lower than that of the infraumbilical channels 12-16 during MDT. In contrast, the ratios were higher in the epigastric channels than in the infraumbilical channels after a test meal. Significant differences between the epigstric and infraumbilical channels were found in the comparisons of the power content ratios. The infraumbilical channels were facilitated and the epigastric channels inhibited during MDT. After eating a meal, in contrast, the postprandial epigastric 3-cpm EGGs were facilitated. The epigastric 3-cpm EGG activity reflects gastric myoelectric activity, while the infraumbilical 3-cpm activity reflects that of the colon. Therefore, it is suggested that the acute stress of the MDT generally inhibited the gastric EGG and facilitated the colonic EGG, indicating gastric inhibition and colonic facilitation. The topographic EGG maps of the power content ratios and the absolute power ratios visually confirmed these findings.

Multi-channel electrogastrography and autonomic nervous system function in patients with non-erosive reflux disease and reflux esophagitis

To investigate the gastric myoelectrical activity and autonomic nervous system (ANS) function in patients with non-erosive reflux disease (NERD) and reflux esophagitis (RE). 42 patients with gastroesophageal reflux disease (GERD), 21 with NERD and 21 with RE, and 20 healthy volunteers (controls) underwent multi-channel electrogastrography (MEGG) and electrocardiography simultaneously for 30 min in the fasting state and 60 min after a standard test meal. The MEGG parameters included dominant frequency (DF), dominant power (DP), normal percentage of 2 - 4 times/min gastric slow waves (N%), and percentage of slow wave coupling (%SWC). ANS was determined according to power spectra analysis of heart rate variability (HRV) which was conducted by using electrocardiogram recording, including the parameters of sympathetic activity, vagal activity, and sympathovagal balance ratio so as to evaluate the ANS function. The DF levels of the NERD and RE patients and healthy volunteers after test meal were all significantly higher than those in fasting state (all P < 0.05). The %SWC levels of the 3 groups after test meal were all significantly lower than those when fasting (all P < 0.05), and the %SWC level of the NERD patients was significantly lower than that of the healthy volunteers in fasting state [70.5% (40.6% - 81.9%, 76.3% (66.4% - 91.4%), P < 0.05]. Test meal significantly increased the sympathetic activity and sympathovagal balance ratio of the NERD and RE patients and healthy volunteers (all P < 0.05), and the vagal activity levels of the 3 groups after test meal were all significantly lower than those when fasting (all P < 0.01). The sympathovagal balance ratio of the NERD group was significantly lower than that of RE group after meal [1.4 (0.8 - 2.5), 2.2 (1.3 - 4.4), P < 0.05]. The spatial regularity of gastric slow waves and ANS function in NERD patients are significantly different from those in RE patients.

Use of multichannel electrogastrography for noninvasive assessment of gastric myoelectrical activity in dogs

To evaluate whether changes in gastric myoelectrical activity in healthy, awake dogs can be detected via multichannel electrogastrography (EGG). 6 healthy hound-breed dogs. For each dog, 8-channel EGG was performed after food had been withheld for 12 hours and at 30 minutes after subsequent feeding; 60 minutes after feeding, atropine (0.04 mg/kg) was administered IM to induce ileus, and 30 minutes later, EGG was again performed. Mean cycles per minute (cpm) values of the dominant frequency (a measure of the rhythmicity of gastric electrical activity) and mean power ratios (ie, power measured after treatment divided by the power measured when food was withheld) were calculated. Motility of the gastric antrum was assessed via B-mode ultrasonography during the same phases; contractions determined ultrasonographically were correlated with EGG power for each channel in each phase. The criterion for stability (SD of the dominant frequency < 15% of the cpm value in at least 3 of the 8 EGG channels) was met in 4 of the 6 dogs (only in long-distance channels). The mean power ratios were significantly higher in the postprandial phase than in the ileus phase. Compared with the postprandial phase, significantly fewer contractions per minute were evident ultrasonographically in the ileus and food-withholding phases. There was a significant and good correlation between EGG power and ultrasonographic findings in all 8 channels. Electrogastrography may be useful in assessing gastric myoelectrical activities in awake dogs with naturally occurring gastrointestinal disease, including gastric dilatation-volvulus.

The influence of opioids on gastric function: experimental and clinical studies

BACKGROUND: Opioids have inhibitory effects on gastric motility, but the mechanism is far from clear. Electrical slow waves in the stomach determine the frequency and the peristaltic nature of gastric contractions. The primary aim of this study was to investigate the effects of the opioid fentanyl on gastric myoelectric activity. As there were large variations between the subjects, we investigated whether the variation was correlated to single nucleotide polymorphisms (SNP) of the mu-opioid receptor (MOR) gene. METHODS: We used cutaneous multichannel electrogastrography (EGG) to study myoelectrical activity in 20 patients scheduled for elective surgery. Fasting EGG was recorded for 30 min, followed by intravenous administration of fentanyl 1 microg/kg and subsequent EGG recording for 30 min. Spectral analysis of the two recording periods was performed and the variables assessed were dominant frequency (DF) of the EGG and its power (DP). Genetic analysis of the SNP A118G and G691C of the MOR gene was performed with the polymerase chain reaction technique. RESULTS: There was a significant reduction in DF and DP after intravenous fentanyl. However, there was a large variation between the patients. In eight subjects EGG was unaffected, five subjects had a slower DF (bradygastria) and in six subjects the slow waves disappeared. We found no correlation between the EGG outcome and the presence of A118G or G691C in the MOR gene. CONCLUSIONS: Fentanyl inhibited gastric myoelectrical activity in about half of the subjects. The variation could not be explained by SNP in the MOR gene. Because of small sample size, the results must be regarded as preliminary observations.

Effects of fentanyl on gastric myoelectrical activity: a possible association with polymorphisms of the μ‐opioid receptor gene?

Opioids have inhibitory effects on gastric motility, but the mechanism is far from clear. Electrical slow waves in the stomach determine the frequency and the peristaltic nature of gastric contractions. The primary aim of this study was to investigate the effects of the opioid fentanyl on gastric myoelectric activity. As there were large variations between the subjects, we investigated whether the variation was correlated to single nucleotide polymorphisms (SNP) of the mu-opioid receptor (MOR) gene. We used cutaneous multichannel electrogastrography (EGG) to study myoelectrical activity in 20 patients scheduled for elective surgery. Fasting EGG was recorded for 30 min, followed by intravenous administration of fentanyl 1 microg/kg and subsequent EGG recording for 30 min. Spectral analysis of the two recording periods was performed and the variables assessed were dominant frequency (DF) of the EGG and its power (DP). Genetic analysis of the SNP A118G and G691C of the MOR gene was performed with the polymerase chain reaction technique. There was a significant reduction in DF and DP after intravenous fentanyl. However, there was a large variation between the patients. In eight subjects EGG was unaffected, five subjects had a slower DF (bradygastria) and in six subjects the slow waves disappeared. We found no correlation between the EGG outcome and the presence of A118G or G691C in the MOR gene. Fentanyl inhibited gastric myoelectrical activity in about half of the subjects. The variation could not be explained by SNP in the MOR gene. Because of small sample size, the results must be regarded as preliminary observations.

T1323 Do Different Types of Patients with Functional Dyspepsia in ROME III Criteria Vary in Related Pathophysiological Mechanisms?

BACKGROUND: In Rome III criteria, patients with functional dyspepsia (FD) are divided into: epigastric pain syndrome (EPS), postprandial discomfort syndrome (PDS) and EPS+PDS. Now, it remains unknown whether differences in the FD related pathophysiological mechanisms exit among them. If the differences are detected, it will be very helpful to treat different types of FD patients according to their special pathophysiologies. AIMS: To investigate the differences in FD related pathophysiologies including gastric solid emptying (GE), gastric muscular electrical activity (GME), autonomic nerve system function (ANS), gastric accommodation/sensitivity and abnormal psychological factors among EPS, PDS and EPS+PDS types of FD patients. METHODS: 77 FD patients according to Rome III criteria (57F, mean age 44.8yrs, EPS 17, PDS 34, EPS+PDS 26) were enrolled in this study. GE, GME, ANS, gastric accommodation/sensitivity and abnormal psychological factors were measured by GE test (radionuclide and radiopaque maker methods), multi-channel electrogastrography, heart rate variability analyzer, liquid nutrient load test (LNLT) and Zung Anxiety/Depression Scale, respectively. The study was approved by the ethics committee of PUMC Hospital. RESULTS: 1. No significant differences exited in age, sex and course of FD among the three types (P>0.05). 2. Delayed GE%: EPS vs. PDS vs. EPS+PDS 33.3% vs. 36.7% vs. 40.0% (P= 0.912). 3. GME: Normal percentage of 2-4cpm gastric slow waves: fasting 78.9±10.6% vs. 75.2±15.0% vs. 69.9±19.0% (P=0.209) and postprandial 71.0±14.0% vs. 71.6±15.2% vs. 62.6±17.3% (P=0.097). Percentage of slow wave coupling%: fasting 67.5±17.0% vs. 64.9±21.2% vs. 61.5±23.3% (P=0.684) and postprandial 62.0±15.7% vs. 59.2±19.6% vs. 50.9±18.1% (P=0.138). 4. LNLT: Maximal Intake Volume: 511±140 vs. 451±129 vs. 480±148ml (P=0.431). 5. ANS: Sympathetic Activity: fasting 0.46±0.28 vs. 0.36±0.19 vs. 0.45±0.14 (P=0.174) and postprandial 0.51±0.17 vs. 0.51±0.19 vs. 0.54±0.13 (P=0.821). Vagal Activity: fasting 0.62±0.17 vs. 0.64±0.19 vs. 0.55±0.14 (P=0.156) and postprandial 0.49±0.17 vs. 0.49±0.19 vs. 0.46±0.13 (P=0.821). 6. Zung Anxiety Scale: 45.6±9.4 vs. 48.4±10.1 vs. 49.7±9.5 (P=0.430) and Zung Depression Scale: 49.5±10.4 vs. 55.1±10.4 vs. 55.8±8.6 (P=0.112). CONCLUSIONS: No differences in the FD related pathophysiologies including GE, GME, ANS, gastric accommodation/sensitivity and abnormal psychological factors were detected among EPS, PDS and EPS+PDS types of FD patients, which suggests that the sub-grouping method of EPS, PDS and EPS+PDS is helpless to the treatment strategy“to treat different types of FD patients according to their special pathophysiologies”.

Multichannel electrogastrography under a magnifying glass – an in‐depth study on reproducibility of fed state electrogastrograms

We checked on reproducibility of parameters of a multichannel electrogastrogram in adults after intake of typical, applied in electrogastrography, test meals. Recordings of multichannel electrogastrograms were accomplished in four blocks comprising 18 subjects (nine healthy volunteers and nine patients with functional GI disorders) each. Every subject had two examinations taken 1-2 days apart, and a third one was accomplished at least 2 weeks before or after the two other sessions. The registration involved a 30-min fasted and a 2-h postprandial period after one of the meal stimuli tested within a given block: 400 mL water, 400 g yoghurt (378 kcal), a scrambled eggs sandwich (370 kcal), a pancake (355 kcal). From among the parameters reflecting the propagation of the gastric slow waves, the average percentage of slow wave coupling (APSWC) exhibited a good (coefficient of variation for paired examinations CV(p) < or = 10%) to moderate (10 < CV(p) < or = 30%) reproducibility. On the other hand, the reproducibility of the maximum dominant frequency difference and the spatial dominant power difference was found to be unsatisfactory. The reproducibility of the multichannel electrogastrographic parameters did not differ between healthy volunteers and patients with functional GI disorders. Gender or the kind of a test meal did not affect the reproducibility of the electrogastrographic parameters either. The medium-term reproducibility was not any worse than the short-term one. From among the parameters of a multichannel electrogastrogram intended to quantify the propagation of slow waves, only the APSWC offers a reproducibility potentially good enough for clinical applications.