Gastric Dysrhythmias Research Articles

A Causal Role for Gastric Rhythm in Human Disgust Avoidance

SummaryRotten food, maggots, bodily waste—all elicit disgust in humans. Disgust promotes survival by encouraging avoidance of disease vectors1 but is also implicated in prejudice toward minority groups; avoidance of environmentally beneficial foods, such as insect protein; and maladaptive avoidance behavior in neuropsychiatric conditions.2, 3, 4, 5 Unlike fear, pathological disgust is not improved substantially by exposure therapy clinically,6 nor in experimental work does behavioral avoidance of disgusting images habituate following prolonged exposure.7,8 Under normal physiological conditions, perception of disgusting stimuli disrupts myoelectrical rhythms in the stomach,9, 10, 11, 12, 13 inducing gastric dysrhythmias that correlate with neural signatures of disgust.11 However, the causal role of gastric rhythm in disgust avoidance is unknown. We manipulated gastric rhythm using domperidone, a peripheral dopamine D2/D3 antagonist and common anti-emetic, at a dose (10 mg) that acts to convert gastric dysrhythmias to normal rhythms.9 In a preregistered, randomized, double-blind, placebo-controlled crossover design in 25 healthy volunteers (aged 18–25), we measured the effects of domperidone on core disgust avoidance, using eye tracking to measure implicit (oculomotor) avoidance of disgusting images (feces) before and after an “exposure” intervention (monetary reinforcement for looking at disgusting images).7,8 We find that domperidone significantly reduces oculomotor disgust avoidance following incentivized exposure. This suggests that domperidone may weaken the “immunity” of disgust to habituation, putatively by reducing gastric dysrhythmias during incentivized engagement with disgusting stimuli. This indicates a causal role for disgust-related visceral changes in disgust avoidance, supporting the hypothesis that physiological homeostasis contributes to emotional experience.

Clinical features and gastric myoelectrical activity in patients with idiopathic and post‐surgical rapid gastric emptying who present with unexplained chronic nausea

The cause of chronic nausea can be difficult to diagnose. Idiopathic rapid gastric emptying (iRGE) can cause nausea, but limited literature exists on clinical and pathophysiological features. In contrast, dumping syndrome or post-surgical rapid gastric emptying (psRGE) is well-known and may present with early phase vasomotor symptoms, diarrhea, and late phase reactive hypoglycemia. Our aim is to compare clinical and gastric motility characteristics in patients with iRGE and psRGE and unexplained chronic nausea. A retrospective study was conducted on patients with unexplained chronic nausea and RGE (<30% retention of a standard isotope-labeled solid meal at 1-h). Gastric myoelectrical activity (GMA) was recorded during water load satiety tests (WLST) using validated electrogastrogram (EGG) recording methods. Thirty iRGE and sixteen psRGE patients with unexplained chronic nausea were identified; average 1-hour meal retention was 18.6% and 16.2%, respectively. Nausea, bloating, early satiety, and bowel function were similar in the two groups; fewer iRGE patients had abdominal pain and none had vasomotor symptoms. Normal 3cpm GMA was recorded in 44% of iRGE vs 29% of psRGE, tachygastria in 13% vs 43%, bradygastria in 25% vs 14%, and mixed in 19% vs 14% (p values >0.05). Abnormal WLST volume (<300ml) was found in 69% of iRGE and 43% of psRGE (p=0.36). (a) iRGE and psRGE patients may present with unexplained chronic nausea rather than classic vasomotor symptoms and diarrhea. (b) iRGE and psRGE patients had similar gastric dysrhythmias and accommodation dysfunction, which may contribute to RGE.

Transmural Temperature Monitoring to Quantify Thermal Conduction And Lesion Formation During Gastric Ablation, an Emerging Therapy for Gastric Dysrhythmias.

Gastric ablation is emerging as a potential therapy for electrical dysrhythmias associated with gastric disorders. Thermal conduction properties of gastric tissue during ablation have not yet been defined, but are necessary for optimizing the technique and translating ablation to clinical therapy. We developed custom needle-based transmural temperature probes to quantify the temperature of gastric tissue during ablation. These probes were applied in vivo in pigs (n=5), during gastric ablation (70 °C, 10 s duration), at distances of 2.5 - 20 mm from the ablation catheter tip. Thermal response of the tissue was non-linear; the maximum temperature increase from baseline (33.3 ± 1.0 °C) was observed at the closest temperature probe to the catheter tip (2.5 mm, 14.9 °C), and temperature change decreased with distance from the catheter tip. Probes positioned between 5 -20 mm from the catheter tip recorded temperature increases of less than 5.6 °C. This study provides methods for monitoring temperature during in vivo ablation, and demonstrates that functional temperature increases from ablation were restricted to within approximately 5 mm of the catheter. These methods can now be applied to optimize effective ablation parameters, and to inform models of gastric ablation.

A V-Net Based Deep Learning Model for Segmentation and Classification of Histological Images of Gastric Ablation.

Gastric motility disorders are associated with bioelectrical abnormalities in the stomach. Recently, gastric ablation has emerged as a potential therapy to correct gastric dysrhythmias. However, the tissue-level effects of gastric ablation have not yet been evaluated. In this study, radiofrequency ablation was performed in vivo in pigs (n=7) at temperature-control mode (55-80°C, 5-10 s per point). The tissue was excised from the ablation site and routine H&E staining protocol was performed. In order to assess tissue damage, we developed an automated technique using a fully convolutional neural network to segment healthy tissue and ablated lesion sites within the muscle and mucosa layers of the stomach. The tissue segmentation achieved an overall Dice score accuracy of 96.18 ± 1.0 %, and Jacquard score of 92.77 ± 1.9 %, after 5-fold cross validation. The ablation lesion was detected with an overall Dice score of 94.16 ± 0.2 %. This method can be used in combination with high-resolution electrical mapping to define the optimal ablation dose for gastric ablation.Clinical Relevance-This work presents an automated method to quantify the ablation lesion in the stomach, which can be applied to determine optimal energy doses for gastric ablation, to enable clinical translation of this promising emerging therapy.

Effects of electroacupuncture on stress-induced gastric dysrhythmia and mechanisms involving autonomic and central nervous systems in functional dyspepsia.

Electroacupuncture (EA) is widely used as an effective method to treat stress-related disorders. However, its mechanisms remain largely unknown. The aim of this study was to investigate the effects and mechanisms of EA on gastric slow wave (GSW) dysrhythmia and c-Fos expression in the nucleus of the solitary tract (NTS) induced by stress in a rodent model of functional dyspepsia (FD). Rats in the neonatal stage were treated using intragastric iodoacetamide. Eight weeks later, the rats were implanted with electrodes in the stomach for the measurement of GSW and electrodes into accupoints ST36 for EA. Autonomic functions were assessed by spectral analysis of heart rate variability. Rats were placed for 30 min in a cylindrical plastic tube for acute restraint stress. The involvement of a central afferent pathway was assessed by measuring c-Fos-immunoreactive cells in the NTS. 1) EA normalized restraint stress-induced impairment of GSW in FD rats. 2) EA significantly increased vagal activity (P = 0.002) and improved sympathovagal balance (P = 0.004) under stress in FD rats. 3) In FD rats under restraint stress, plasma norepinephrine concentration was increased substantially (P < 0.01), which was suppressed with EA. 4) The EA group showed increased c-Fos-positive cell counts in the NTS compared with the sham EA group (P < 0.05) in FD rats. Acute restraint stress induces gastric dysrhythmia in a rodent model of FD. EA at ST36 improves GSW under stress in FD rats mediated via the central and autonomic pathways, involving the NTS and vagal efferent pathway.

490 High-Resolution Electrogastrogram Identifies Disturbed Gastric Slow Waves and Dysautonomia in Subjects With Dumping Syndrome

INTRODUCTION: Rapid gastric emptying is the sine qua non of Dumping Syndrome (DS), which can arise from multiple etiologies including gastric surgery and diabetes mellitus. The relationship between DS and gastric myoelectric activity is unknown, but dysautonomia may play a role. We sought to characterize features of gastric slow waves and autonomic indices among subjects with DS using the ambulatory high-resolution electrogastrogram (HR-EGG). METHODS: Eleven subjects completed 24-hour ambulatory HR-EGG. Fasting abdominal computed tomography scan was utilized for stomach localization and placement of the ambulatory HR-EGG array, consisting of 10 skin mounted electrodes. Subjects were divided into two groups: DS (4F, age 53.2 ± 9.3, BMI 31.7 ± 11, 79-93% gastric emptying at 1 hour on scintigraphy, two diabetics, one prior gastric surgery, one gastrointestinal amyloidosis) and healthy age-matched controls (4M/3F, age 47.6 ± 28, BMI 24.5 ± 3.7). All subjects completed the PAGI-SYM foregut symptom questionnaire and a diary capturing all meals and sleep/wake times. RESULTS: Subjects with DS had significantly higher mean PAGI-SYM foregut symptom severity scores (1.9 ± 1.0 vs 0.1 ± 0.1; P = 0.0007). HR-EGG showed that DS subjects had a significantly lower slow wave speed (4.6 vs 5.9 ± 0.4; P = 0.0003) and higher post-prandial power change (11 vs 3.5 ± 3.6; P = 0.002) compared to healthy controls. The global percent stomach activity throughout the 24-hour ambulatory recordings was not different between groups. DS subjects trended towards higher post-prandial area under the curve EGG activity at both the 1-hour (261.9 ± 360.7 vs 172.9 ± 137.5) and 4-hour marks (1108.8 ± 1589.4 vs 656.3 ± 442.2). In addition, subjects with DS had significantly lower heart rate variability than controls: RMSDD (39.9 ± 9.7 vs 58.1 ± 7.8) and SDNN (12.6 ± 4.2 vs 23.7 ± 3.2); no differences were noted in mean heart rate (Table 1). CONCLUSION: Ambulatory HR-EGG clearly identifies that there are spatial abnormalities of the gastric slow wave present among subjects with DS. Moreover, reduced heart rate variability - a marker of autonomic dysfunction - was observed among subjects with DS. These findings suggest that gastric dysrhythmias and autonomic disturbances should be given important consideration in the pathogenesis of Dumping Syndrome.

Self-Powered Coiled Carbon-Nanotube Yarn Sensor for Gastric Electronics.

The strong peristaltic contraction of the stomach facilitates mixing and emptying of ingested food, which occurs rhythmically at approximately 3 cycles/min (cpm) in humans. Generally, most patients with gastroparesis show gastric electrical dysrhythmia that is disrupted electrical signals controlling gastric contractions. For treatment of gastric electrical dysrhythmia, in vivo electrical impulses to the stomach via an implanted gastric stimulator have been known to restore these gastric deformations. Nevertheless, improved sensors to monitor gastric contractions are still needed in current gastric stimulators. Recently, we have developed a new technology converting mechanical motion to electrical energy by using stretch-induced capacitance changes of a coiled carbon-nanotube (CNT) yarn. For its potential use as a gastric deformation sensor, the performance of a coiled CNT yarn was evaluated in several biological fluids. For a sinusoidal stretch to 30%, the peak-to-peak open-circuit voltage (OCV) was consistently generated at frequencies below 0.1 Hz. This sinusoidal variation in OCV augmented as the strain increased from 10 to 30%. In an in vitro artificial gastric system, the OCV was approximately linearly proportional to the balloon volume, which can monitor periodic deformations of the balloon at 2, 3, and 4 cpm as shown for human gastric deformations. Moreover, stretchy coiled yarns generate the peak electrical voltage and power when deformed. The present study shows that a self-powered CNT yarn sensor can not only monitor the changes in frequency and amplitude of volumetric change but also generate electrical power by periodic deformations of the balloon. Therefore, it seems possible to automatically deliver accurate electrical impulses according to real-time evaluation of a patient's gastric deformation based on information on the frequency, amplitude, and rate of the OCV from CNT yarn.

Feasibility of High-Resolution Electrical Mapping for Characterizing Conduction Blocks Created by Gastric Ablation.

The interstitial cells of Cajal (ICC) initiate, coordinate and propagate bioelectrical slow wave activity that drives gastric motility. In the healthy human stomach, slow wave activity is highly organized. Gastric motility disorders are associated with dysrhythmias. While ablation is widely used to treat cardiac dysrhythmias, this approach has yet to be trialed in the stomach. In this study, radiofrequency (RF) ablation was applied in pig stomachs in vivo to create targeted electrical conduction blocks. Ablations were performed at temperature control mode (55-70°C), and resultant conduction blocks were identified and verified using high-resolution electrical mapping. Termination of slow wave propagation at ablation sites was confirmed by a decrease in extracellular slow wave amplitude from 1.7 ± 0.2 mV to an undetectable amplitude, as well as spatiotemporal pattern analysis of conduction blocks. The use of high-resolution electrical mapping can now be employed to investigate ablation as a potential therapy for gastric dysrhythmias in motility disorders.

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.

Gastric Myoelectrical Activity and Autonomic Nervous System Abnormalities in Patients with Chronic Unexplained Nausea and Vomiting and in Patients with Gastroparesis

Background: Patients with chronic unexplained nausea and vomiting (CUNV) and Gastroparesis (GP) have similar symptoms, suggesting they share pathophysiological abnormalities along a continuum of disease.Objectives: To determine the incidence of gastric myoelectrical, accommodation dysfunction and autonomic abnormalities in patients with CUNV and GP.Methods: Outpatients with CUNV and GP who underwent standard 4-hr solid phase gastric emptying, upright tilt table test and electrogastrogram (EGG) recordings with water load satiety test (WLST) were identified from chart review. Subjects with normal emptying were in the CUNV group; those with delayed emptying were in the GP group. EGGs were recorded before and 30 minutes after the WLST and symptoms were recorded on a 100mm visual analog scale.Results: 44 patients (35 women and 9 men, ages 17-76 years) were identified: 24 had normal gastric emptying and CUNV and 20 had GP. Gastric dysrhythmias were found in 70% of CUNV and 69% of GP patients. Twenty percent of CUNV patients and 44% of GP patients ingested abnormally low volumes (&lt; 300mL) during the WLST. Nausea increased similarly after the WLST in the subjects with CUNV and GP (Ps &gt; 0.05). Postural orthostatic tachycardia syndrome (POTS) was diagnosed in 17% of CUNV patients and 20% of GP patients.Conclusions: Gastric myoelectrical and accommodation abnormalities and autonomic nervous system (ANS) dysfunctions frequently occur in subjects with CUNV and GP. These pathophysiological abnormalities support the idea that CUNV and GP occur along the same continuum of gastric neuromuscular dysfunction and may be targets for therapeutic approaches.&#x0D;

Mo1046 DELAYED GASTRIC EMPTYING SECONDARY TO POEM PROCEDURE: A RARE CASE OF GASTROPARESIS

A 42-year-old man came to our clinic complaining recurrent difficult swallowing for 18 years and upper abdominal fullness for 2 years. He has been suffered from difficult swallowing, regurgitation, vomiting and occasional posterior sternal pain since 2000. He was diagnosed of achalasia (Eckardt score: 8) (Figure 1) and the symptoms were greatly relieved after balloon dilation (BD) (Eckardt score: 2) in 2010. Unfortunately, he relapsed into achalasia (Eckardt score: 8) and then underwent peroral endoscopic myotomy (POEM) (Eckardt score: 7). However, although the pre-operation barium meal showed no sign of gastric retention, the patient began to develop some new symptoms of delayed gastric emptying such as gastral pattern and early satiety which cannot be aniseed by prokinetic drugs (GCSI score: 24). Gastric retention was first confirmed by gastric endoscopy in March 2017, while pylorus stenosis was confirmed by both barium meal and gastric endoscopy in June 2017. Electrogastrogram revealed a gastric dysrhythmia before and after meal, and gastric emptying after 5 h was only 5% (normal: ≥ 50%) (Figure 2, left). Multiple blood test (glycemia, cancer biomarkers, immune parameters), CT and biopsy exclude carcinoma, diabetes or autoimmune disease. To eliminate the symptoms, the patient received gastric peroral endoscopic myotomy (G-POEM) procedure in April 2018. Barium meal showed normal gastric emptying (Figure 2, right), and pyloric was round without stricture under gastric endoscopy in 7 months follow-up (GCSI score: 11). Nevertheless, his Eckardt score remained at 6 and BD was performed recently in our institution. The post-operation barium meal and patients’ symptoms were improved after BD.

Mo1620 – Distension-Induced Gastric Slow Wave Dysrhythmias Defined by High-Resolution Electrical Mapping in the Pig

Mo1620 – Distension-Induced Gastric Slow Wave Dysrhythmias Defined by High-Resolution Electrical Mapping in the Pig

High-resolution Mapping of Hyperglycemia-induced Gastric Slow Wave Dysrhythmias.

Background/AimsIt is now recognised that gastric dysrhythmias are best characterised by their spatial propagation pattern. Hyperglycemia is an important cause of gastric slow wave dysrhythmia, however, the spatiotemporal patterns of dysrhythmias in this context have not been investigated. This study aims to investigate the relationship between hyperglycemia and the patterns of dysrhythmias by employing high-resolution (multi-electrode) mapping simultaneously at the anterior and posterior gastric serosa.MethodsHigh-resolution mapping (8 × 16 electrodes per serosal) was performed in 4 anesthetized hounds. Baseline recordings (21 ± 8 minutes) were followed by intravenous injection of glucagon (0.5 mg per dose) and further recordings (59 ± 15 minutes). Blood glucose levels were monitored manually using a glucose sensing kit at regular 5-minute intervals. Slow wave activation maps, amplitudes, velocity, anisotropic ratio, and frequency were calculated. Differences were compared between baseline and post glucagon injection.ResultsBaseline slow waves propagated symmetrically and antegrade. The blood glucose levels were increased by an average of 112% compared to the baseline by the end of the recordings. All subjects demonstrated elevated incidence of slow wave dysrhythmias following injection compared to the baseline (48 ± 23% vs 6 ± 4%, P < 0.05). Dysrhythmias arose simultaneously or independently on anterior and posterior serosa. Spatial dysrhythmias occurred before and persisted after the onset and disappearance of temporal dysrhythmias.ConclusionsInfusion of glucagon induced gastric slow wave dysrhythmias, which occurred across a heterogeneous range of patterns and frequencies. The spatial dysrhythmias of gastric slow waves were shown to be more prevalent and persisted over a longer period of time compared to the temporal dysrhythmias.

Prokinetic effects of spinal cord stimulation and its autonomic mechanisms in dogs.

Spinal cord stimulation (SCS) is widely used to treat chronic pain by inhibiting sympathetic activity; however, it is unknown whether it exerts a prokinetic effect on gastric motility. Our aim was to explore effects and possible mechanisms of SCS on glucagon-induced gastric dysmotility and dysrhythmia. Seven female dogs with electrodes chronically placed on the dorsal column of the spinal cord between T10 and T12 segments were studied in 2 randomized sessions (glucagon+sham-SCS, glucagon+SCS). SCS at T10 using a set of optimized stimulation parameters was performed for 30minute immediately after glucagon injection. The antral manometry, electrogastrogram, and electrocardiogram were recorded to assess gastric contractions, gastric slow waves (GSW), and autonomic functions, respectively. (a) Compared to baseline, glucagon decreased antral motility index (MI) (6315±565 vs 3243±775, P<0.001), reduced the percentage of normal GSW (89±3% vs 58±3%, P<0.01), and increased sympathetic activity (0.25±0 0.06 vs 0.60±0.07, P<0.01). (b) The sympathetic activity was negatively correlated with antral MI (r=-0.558; P<0.01) and the percentage of gastric normal slow wave (r=-0.616; P<0.01). (c) SCS prevented the glucagon-induced impairment in antral hypomotility (MI: 5770±927 vs 5521±1238, P>0.05) and GSW abnormalities (% of normal waves: 84±4% vs 79±6%, P>0.05) and sympathetic activity (0.27±0.03 vs 0.33±0.07, P>0.05). Spinal cord stimulation dramatically improves glucagon-induced impairment in gastric contractions and slow waves by inhibiting sympathetic activity.

Idiopathic Dumping Syndrome in Patients Presenting with Chronic Unexplained Nausea

Introduction: Dumping syndrome is a well—known complication after gastric surgery. However, limited literature exists on idiopathic dumping syndrome. Our aim is to investigate the clinical characteristics of non—surgical patients with rapid gastric emptying who present with unexplained chronic nausea. Methods: A retrospective study was conducted on patients who had severe rapid gastric emptying, defined as gastric retention <30% at one hour during a four—hour isotope—labeled solid meal test. These patients were identified by chart review and were seen in a Neurogastroenterology Clinic at an academic institution between January 2011 and December 2017 for nausea and other unexplained gastrointestinal symptoms. Results: Forty—six patients were identified with severe rapid gastric emptying; sixteen were excluded due to previous gastric surgeries. The remaining thirty non—surgical patients (50% females, mean age 49 years, mean BMI 28) had a mean gastric retention of 19% (range 2% to 30%) at one hour. Thirteen (43%) had diabetes, and nine (30%) were insulin dependent. Six patients (20%) had a previous diagnosis of gastroparesis. All patients presented with unexplained nausea, fifteen (50%) had early satiety, and fifteen (50%) had bloating. Variations in bowel habits were reported as follows: 26% with diarrhea, 27% with constipation, 10% with diarrhea and constipation, and 27% with normal bowel movements. Sixteen (53%) patients had electrogastrogram tests: 69% had poor water load satiety test (ingested <557 mL in five min), 13% had tachygastria, 25% had bradygastria, 19% had mixed tachygastria and bradygastria, and 44% were normal. Five patients (17%) had positive breath tests for small bowel bacterial overgrowth. Conclusion: 1. Patients with severe idiopathic rapid gastric emptying may present with nausea and gastroparesis—like symptoms rather than vasomotor symptoms and diarrhea typically seen in postsurgical dumping syndrome; 2. Over half of the patients had risk factors for abnormal gastric motility, such as diabetes, poor water load satiety tests, and gastric dysrhythmias, which may contribute to altered emptying rates; 3. Physiological mechanisms underlying rapid gastric emptying warrants further investigations; and 4. Rapid gastric emptying should be considered in patients who present with chronic unexplained nausea without previous gastric surgeries.

Central and Peripheral Effects of Transcutaneous Acupuncture Treatment for Nausea in Patients With Diabetic Gastroparesis

Background/Aims Nausea, an unpleasant symptom of diabetic gastroparesis (DMGP), has been reported to be alleviated by needleless transcutaneous electrical acupuncture (TEA). Our study was designed to utilize electroencephalography (EEG) and electrogastrography (EGG) recordings to investigate the central and peripheral responses of TEA in the treatment of nausea in DMGP patients. Methods Eleven DMGP subjects underwent simultaneous EEG and EGG testing while grading the severity of nausea following 30-minute intervals of: (1) baseline, (2) visual stimulation (VS) to provoke more nausea, (3) active VS together with TEA, and (4) TEA alone, and a final 15-minute recording without any intervention. Results The nausea score was increased to 5.9 ± 1.5 with VS (P < 0.05, vs 3.5 ± 1.0 at baseline), then reduced to 3.5 ± 1.2 with VS plus TEA, and to 2.5 ± 1.3 with TEA alone, while it continued at a score of 2.9 ± 1.0 post TEA (all significant, P < 0.05, vs VS without TEA). The mean percentage of normal gastric slow waves was decreased to 60.0 ± 5.7% with VS (P < 0.05, vs 66.6 ± 4.5% at baseline), then improved to 69.2 ± 4.8% with VS plus TEA, and maintained at 70 ± 3.6% with TEA alone. During initial VS, EEG signals showed right inferior frontal activity as the prominent finding, but during VS with TEA, left inferior frontal activity predominated. Conclusions In DMGP, TEA improves gastric dysrhythmia and ameliorates nausea. TEA treatment of nausea provoked by VS resulted in a change of dominance from right to left inferior frontal lobe activity. These data provide new understandings of peripheral and central mechanisms for nausea, and potential future directions for DMGP treatment approaches.

Gastric Dysrhythmia Corrected by Dual Chamber Pacemaker Implantation

HighlightsNausea has been defined as an “unpleasant painless subjective feeling that one will imminently vomit”. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea. The underlying mechanisms involved in nausea are complex and encompass psychological states, the central nervous system, autonomic nervous system, gastric dysrhythmias, and the endocrine system. We report a 92-year-old male patient with depression, hypothyroidism, and intermittent severe sinus dysfunction, causing nausea, vomiting, and fatigue, pre-syncope and low cerebral output. Dual chamber implantation was performed and 24 hours after the implantation of the device all the symptoms disappeared, the parameters of the pacemaker were stable, and the patient was discharged. At the 1st and the 3rd month after implantation the patient remained asymptomatic. Over-activity of autonomic outflow may be a determinant for overall nausea intensity, probably, may be a potential therapeutic target to be corrected, at least in part, by a dual chamber pacemaker implantation.

Noninvasive Magnetogastrography Detects Erythromycin-Induced Effects on the Gastric Slow Wave

The prokinetic action of erythromycin is clinically useful under conditions associated with gastrointestinal hypomotility. Although erythromycin is known to affect the electrogastrogram, no studies have examined the effects that erythromycin has on gastric slow wave magnetic fields. In this study, gastric slow wave activity was assessed simultaneously using noninvasive magnetogastrogram (MGG), electrogastrogram, and mucosal electromyogram recordings. Recordings were obtained for 30 min prior to and 60 min after intravenous administration of erythromycin at dosages of 3 and 6 mg/kg. MGG recordings showed significant changes in the percentage power distribution of gastric signal after infusion of both 3 and 6 mg/kg erythromycin at t = 1-5 min that persisted for t = 30-40 min after infusion. These changes agree with the changes observed in the electromyogram. We did not observe any statistically significant difference in MGG amplitude before or after injection of either 3 or 6 mg/kg erythromycin. Both 3 and 6 mg/kg erythromycin infusion showed retrograde propagation with a statistically significant decrease in slow wave propagation velocity 11-20 min after infusion. Propagation velocity started returning toward baseline values after approximately 21-30 min for the 3 mg/kg dosage and after 31-40 min for a dosage of 6 mg/kg. Our results showed that the magnetic signatures were sensitive to disruptions in normal slow wave activity induced by pharmacological and prokinetic agents such as erythromycin. This study shows that repeatable noninvasive bio-electro-magnetic techniques can objectively characterize gastric dysrhythmias and may quantify treatment efficacy in patients with functional gastric disorders.

Efficacy of needleless transcutaneous electroacupuncture in synchronization with breathing for symptomatic idiopathic gastroparesis: A blinded and controlled acute treatment trial.

Needleless transcutaneous electroacupuncture (TEA) improves nausea and myoelectrical activity in diabetic gastroparesis (GP). Synchronized TEA (STEA), which combines synchronized breathing with TEA, is more potent than TEA in enhancing vagal activity in healthy subjects. To investigate whether STEA improves symptoms, electrogastrogram (EGG) and vagal activity in idiopathic gastroparesis (IGP). Eighteen IGP subjects underwent 2 randomized visits (sham at non-acupoints or real STEA at acupoints) consisted of a 30-minute baseline, an Ensure challenge to provoke nausea, followed by 60-minute treatment with sham or real STEA, and 15-minute observation period. Severity of nausea, EGG, and vagal activity (based on electrocardiogram and serum Pancreatic Polypeptide, PP) were recorded. In sham or STEA, the nausea scores of 2.7±0.5 and 1.9±0.5 at fasting baseline, respectively, increased to 5.9±0.4 and 5.8±0.3 during Ensure test (P<.05, vs baseline), subsequently reduced to 3.4±0.6 with sham or 3.6±0.6 with STEA, respectively (P<.05, vs Ensure period). Experiments with sham and STEA started with similar % of normal waves on EGG (66.4±3.9 and 61.8±3.0, respectively); decreased to 63. 5±4.1 and 58.2±2.8 during the Ensure test. After STEA, there was ~24% increase in % of normal waves, significantly different from the sham (6.0%) (P<.01). In sham or STEA, vagal activity was identical at baseline and after the Ensure. STEA induced a 3-fold increase in vagal activity compared with sham (P<.01). Ensure increased serum PP levels, and both treatments decreased the PP CONCLUSIONS: In IGP, STEA is not superior to Sham in decreasing nausea, but is more effective in improving gastric dysrhythmia.

Su1634 - Ameliorating Effect and Mechanism of Vagal Nerve Stimulation on Gastric Slow Wave Dysrhythmia Induced by Rectal Distension

Su1634 - Ameliorating Effect and Mechanism of Vagal Nerve Stimulation on Gastric Slow Wave Dysrhythmia Induced by Rectal Distension