Inhibitory reflexive effect of rectal distension on postprandial gastric myoelectrical activity

The aim of the study was to determine the effects of low-volume rectal distension on gastric myoelectrical activity. The study was performed in 14 healthy volunteers in 2 randomized sessions. In the control session, a small balloon was inserted into the rectum 10 cm beyond the anal verge and inflated with 20 ml of air. Gastric myoelectrical activity was recorded for 30 minutes in the fasting state and 30 minutes after a meal; and then the balloon was deflated and removed, and another 30-min recording was followed. The study session was the same except that after the 30-min baseline recording the balloon was inflated to reach a volume with which the subject felt an urgency for defecation. Spectral analyses were performed to compute the dominant frequency, power, and regularity (2–4 cycles/minutes, cpm) of the gastric slow waves and the percentage of gastric dysrhythmia. Results: 1). In comparison with our previously published data, the placement of the rectal balloon with a volume of 20 ml air did not affect the regularity of the slow waves (84.2 ± 3.6% in fasting, 85.3 ± 4.3% in fed); In comparison with the control session, the rectal distension inducing an urgency for defecation (average volume of air: 72.5 ml) significantly reduced the regularity of gastric slow waves in the fed state (72.0 ± 5.7%, P < 0.03 vs baseline; P < 0.02, vs control session) but not in the fasting state (80.1 ± 4.5%, P = 0.1). This postprandial change was attributed to a significant increase in bradygastria (3.1 ± 1.0% vs 7.9 ± 2.6%, P < 0.04) and a marginal increase in tachygastria (7.4 ± 2.5% vs 15.8 ± 4.3%, P = 0.06). The normal postprandial increases in the dominant frequency and power of the gastric slow wave were abolished in both sessions. conclusions, rectal distension evoking an urgency for defecation impairs postprandial gastric slow waves with an increase in the percentage of both bradygastria and tachygastria.     

Abnormal gastric myoelectrical activity and delayed gastric emptying in patients with symptoms suggestive of gastroparesis

Gastric myoelectrical activity modulates gastric motor activity. Abnormalities in gastric myoelectrical activity may be associated with gastric motility disorders. The aim of this study was to investigate the correlation of gastric myoelectrical activity with gastric emptying in symptomatic patients with and without gastroparesis. Ninety-seven patients with symptoms suggestive of gastroparesis participated in the study. Gastric myoelectrical activity was recorded using surface electrogastrography. The electrogastrogram (EGG) was recorded for 30 min in the fasting state and for 120 min after a solid test meal. Gastric emptying of the solid meal was simultaneously monitored for 120 min. Patients with delayed gastric emptying showed a significantly lower percentage of normal gastric slow waves (P<0.03) and a significantly reduced increase of the dominant power in the postprandial EGG (P<0.02). Postprandial EGG parameters were found to be able to predict delayed emptying of the stomach. Postprandial gastric dysrhythmia predicts delayed gastric emptying with an accuracy of 78%, while the abnormality in postprandial EGG power predicts delayed gastric emptying with an accuracy of 75%. All patients with abnormalities in both the rhythmicity and the power had delayed gastric emptying. Patients with delayed gastric emptying have a lower percentage of normal gastric slow waves in the EGG and a lower postprandial increase in the dominant power. Abnormalities in the postprandial EGG seem to be able to predict delayed emptying of the stomach. However, a normal EGG does not seem to guarantee normal emptying of the stomach.     

Effects of highly selective vagotomy on gastric myoelectrical activity

Changes in gastric myoelectrical activity following highly selective vagotomy were studied in 12 patients by means of electrogastrography (EGG) using cutaneous electrodes. Measurements were made before, 10 days after, and six months after operation. Eight patients undergoing cholecystectomy served as controls. Preoperatively all controls and patients had normal recordings. In the cholecystectomized patients no significant changes were found postoperatively. Ten days after highly selective vagotomy the normal initial postprandial dip in gastric ECA frequency and the subsequent increase in frequency and power were not seen. Tachygastrias were observed in three patients. Six months after operation the normal frequency and power responses to a test meal had returned, but both the fasting and postprandial ECA frequencies were raised significantly. It is concluded that highly selective vagotomy is associated with abnormalities in myoelectrical activity, in particular in the postprandial state, most of which are reversible with time.     

Inhibitory effects of various types of stress on gastric tone and gastric myoelectrical activity in dogs

Objective. Stress impairs gastrointestinal motility, causing, for example, delayed gastric emptying and altered intestinal transit. However, little is known about the effect of various stress factors on gastric tone and gastric myoelectrical activity (GMA). The aim of this study was to assess the effect of various kinds of stress on gastric tone and GMA in a canine model. Material andmethods. Six dogs, implanted with a gastric cannula and one pair of gastric seromuscular electrodes, were studied. Three kinds of stress (visual, thermal, or audio stimulation) were applied in separate sessions. GMA and gastric tone were recorded for 30 min at baseline and 30 min during stress. Results. Visual stress (blinding) did not alter gastric tone or GMA; cold stress (ice water) and audio stress (loud noise) significantly inhibited gastric tone: gastric volume was increased from 107.2±13.5 ml at baseline to 135.6±23.8 ml with cold stress (p=0.041), and from 106.4±5.7 ml at baseline to 159.2±15.1 ml with audio stress (p=0.007). Although the dominant frequency or power of gastric slow waves was not altered, the percentage of normal gastric slow waves was markedly reduced from 98.3±0.8 to 87.5±3.7 with cold stress and from 90.2±3.3 to 80.6±2.9 with audio stress (p<0.05). Conclusions. Cold- and audio stress inhibit gastric tone and impair gastric slow waves, whereas visual stress does not seem to have such effects. These findings will help to increase our understanding of gastrointestinal motor disorders related to stress.     

Effects of enhanced viscosity on canine gastric and intestinal motility

BACKGROUND AND AIM: The aim of this study was to investigate the effect of enhanced viscosity on gastric emptying and gastrointestinal motor and myoelectrical activities in dogs. METHOD: The study was performed in eight healthy female hound dogs chronically implanted with four pairs of gastric and two pairs of intestinal serosal electrodes and a duodenal fistula. Each dog was studied in three sessions and fed with three test meals with different viscosity. Gastric emptying was monitored for 2 h simultaneously with gastric and intestinal myoelectrical recordings. RESULTS: The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly delayed gastric emptying but had no effect on postprandial blood glucose levels in comparison with the meal containing no galactomannan. The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly increased the frequency and strength of intestinal motility but had no effect on intestinal slow wave rhythms. The product with enhanced viscosity had no effect on gastric motor activity or gastric slow waves. CONCLUSION: It was concluded that enhanced viscosity delays gastric emptying, increases postprandial intestinal but not gastric motility, and has no effects on gastric or intestinal slow waves.     

Inhibitory effect of white wine on gastric myoelectrical activity and the role of vagal tone

Although extensively investigated throughout the gastrointestinal tract, the influence of alcohol on gastric motility is still unclear. Our aim was to investigate the effect of wine on gastric myoelectrical activity and vagal activity. Ten healthy subjects were studied in two sessions with the electrogastrogram (EGG) for 30 min at baseline, 30 min after ingesting the test liquid [white wine (12.5% alcohol) or matched juice], and 60 min after a standard test meal. Spectral analysis was performed to compute EGG parameters and their postprandial changes. The vagal activity was assessed based on spectral analysis of the heart rate variability (HRV) signal derived from the ECG recording. White wine preload significantly diminished the postprandial increase in EGG dominant power compared to juice preload (1.16 ± 1.57 vs 5.48 ± 1.01 dB, P < 0.001). A significant decrease in vagal activity was observed after wine (23.40 ± 4.30 vs 17.43 ± 3.40%, P < 0.005), which remained unchanged after the test meal (23.40 ± 4.30 vs 16.77 ± 4.40%, P < 0.05). This decrease was not noted in the juice session. A correlation was established between changes after wine consumption in EGG dominant power and in the percentage of the vagal activity (r = 0.89, P < 0.05). In conclusion, white wine preload inhibits the postprandial EGG dominant power, suggesting a possible inhibition of postprandial gastric contractions. This effect may be associated with diminished vagal activity.     

Origins and patterns of spontaneous and drug-induced canine gastric myoelectrical dysrhythmia

The aim of this study was to investigate the characteristics and orientation of gastric dysrhythmia using multichannel serosal recordings in dogs. Ten dogs chronically implanted with four to eight pairs of electrodes were studied. Gastric slow waves were recorded in four sessions: postsurgical and after atropine, vasopressin, and glucagon. A total of 554.7 min of bradygastria, 201 min of tachygastria and 22.3 min of arrhythmia were observed in the recordings. The majority of bradygastria (80.5 ± 9.4%) originated in the proximal stomach (P < 0.04, vs other locations) and propagated all the way to the distal antrum. In contrast, tachygastria mainly originated in the distal antrum (80.6 ± 8.8%) (P < 0.04, vs other locations) and propagated partially or all the way to the proximal stomach. Dysrhythmia appeared intermittently with normal gastric slow waves. In all recordings, normal slow waves were present 38.0 ± 5.3% of the time, while bradygastria, tachygastria, and arrhythmia were present 35.9 ± 5.3%, 23.0 ± 1.6%, and 2.4 ± 0.5% of the time, respectively. The prevalence of dysrhythmia was highest in the distal antrum (80.4%) (P < 0.01) and lowest in the proximal part of the stomach. In conclusion, tachygastria originates from an ectopic pacemaker in the distal antrum. It may completely or partially override the normal slow waves. Bradygastria is attributed to a decrease in the frequency of the normal pacemaker in the corpus. The prevalence of gastric dysrhythmia is different in different locations of the stomach and is highest in the distal antrum.     

Alteration of gastric myoelectrical and autonomic activities with audio stimulation in healthy humans

Cold or emotional stress was reported to affect gastric myoelectrical activity. The aim of this study was to investigate the effects of music or noise on gastric myoelectrical activity and autonomic function in healthy volunteers.

Material and methods

The study was performed in 10 fasted healthy volunteers and included 30 min at baseline, 30 min of classical music via headphones and 30 min of loud household noises via headphones. The electrogastrogram (EGG) readings were recorded simultaneously with the electrocardiogram (ECG) recording.

Results

Both classical music and noise altered the regularity of gastric slow waves. The percentage of normal 2–4 cycles/min (cpm) waves was reduced from 77.9±4.7% at baseline to 66.9±5.4% during music (p<0.006) and 67.7±5.4% during noise (p<0.05). The reduction was attributed to a significant increase in bradygastria (15.8±3.9% versus 9.8±2.6%, p<0.04) with the music and a significant increase in arrhythmia (7.4±1.6% versus 2.0±1.1%, p<0.02) with the noise. The dominant frequency and power of the EGG were, however, not altered with either music or noise. Neither music nor noise had any effect on the autonomic function assessed by the heart rate variability.

Conclusions

Audio stimulation, with both music and noise, alters the rhythmicity of gastric slow waves. Classical music seems to increase bradygastria, whereas, household noise may increase arrhythmia. The effect of audio stimulation on the gastric slow wave does not seem to involve sympathetic or vagal efferent pathways assessed by the spectral analysis of heart rate variability.     

Role of sham feeding in postprandial changes of gastric myoelectrical activity

The aim of this study was to evaluate the role of sham feeding in postprandial changes of gastric myoelectrical activity. Eighteen asymptomatic healthy volunteers (10 men, 8 women; mean age: 31), with no history of gastrointestinal disease were studied. Gastric myoelectrical activity was recorded for 30 min at baseline, 30 min after sham feeding, and 1 hr after eating, using surface electrogastrography. The electrogastrogram (EGG) was analyzed by spectral analysis. It was found that the changes of postprandial EGG parameters were significantly correlated with those after sham feeding (EGG dominant power:r=0.6,P<0.01; dominant frequency:r=0.8,P<0.001; percentage of regular slow waves:r=0.7,P<0.003). We concluded that intrinsic gastric electrical activity can be altered by sham feeding and the cephalic phase of digestion plays an important role in the postprandial response of gastric myoelectrical activity.     

Effect of single-dose administration of recombinant interferon-alpha2b on gastric myoelectrical activity in patients with chronic hepatitis C

Background Upper abdominal complaints during interferon therapy may result from impaired gastric motility and/or evacuatory function. We examined the effect of acute administration of interferon on gastric myoelectrical activity (GMA) with the use of surface electrogastrography.Methods The study population comprised 25 patients with chronic hepatitis C. All of them were naïve to interferon. On 2 days, after a 25-min basal GMA registration, in group A (5 men, 7 women, aged 44.3 ± 2.8 years) placebo or 5 million i.u. recombinant interferon alpha-2b (IFNA) was administered s.c. and the GMA was recorded in the interdigestive state for two periods (2h and 4h), separated by a 15-min break. In group B (7 men, 6 women, aged 44.7 ± 3.9 years) placebo or 5 million i.u. IFNA was injected s.c. after the ingestion of a semiliquid test meal of 364kcal. Subsequently, the postprandial GMA was recorded for two periods (2h and 4h), separated by a 15-min break.Results A typical flu-like syndrome was observed in 91.7% of patients in group A, and in 92.3% of patients in group B, thus providing evidence of the pharmacodynamic efficiency of the IFNA administration. In the fasted state, IFNA brought about a negligible increase in the rhythmicity and power of the gastric slow waves. IFNA did not elicit any statistically significant effect on gastric slow-wave activity postprandially.Conclusions Acute administration of interferon does not involve any deterioration of GMA that could be linked to the previously reported upper abdominal symptoms in patients undergoing treatment with this drug.     

Impaired gastric slow wave rhythmicity in patients after bone marrow or stem cell transplant

Patients after bone marrow or stem cell transplant often develop gastrointestinal symptoms. The aim of this study was to investigate possible impairment of gastric myoelectrical activity in these patients. The study was performed in 15 patients who had had bone marrow or stem cell transplant and 13 healthy subjects. Gastric myoelectrical activity was assessed using electrogastrography. The electrogastrogram (EGG) was made for 30 min in the fasting state and 60 min after a test meal (475 kcal; turkey sandwich). Overall and minute-by-minute spectral analyses were performed to derive various parameters of the EGG. Compared with the healthy controls, the patients showed a significantly higher percentage of arrhythmia (no obvious rhythmicity observed in the EGG) in both fasting (17.6 ± 3.8% vs 7.1 ± 2.17%, P < 0.02) and fed (11.4 ± 2.65% vs 4.19 ± 1.04%, P < 0.02) state. The patients showed a significantly higher instability coefficient of the dominant frequency in the fasting state than in the controls (0.51 ± 0.06 vs 0.29 ± 0.18, P < 0.008). The total average symptom score was 3.93 ± 0.84 in the patients and 0 in the controls, and a relatively weak but significant correlation was found between the symptom scores and the percentage of arrhythmia in the patients in fed state (r = 0.69, P < 0.02). It was concluded that patients with bone marrow or stem cell transplant have excessive arrhythmia that is correlated with their dyspeptic symptoms.     

Dietary influence on electrogastrography and association of alterations in gastric myoelectrical activity with symptoms in patients with functional dyspepsia

Background and Aim: It is unclear which type of meal is adequate in measuring electrogastrography and which parameter of electrogastrography is of clinical relevance. The aims of the present study were to compare the influence of water and a nutrient drink on electrogastrography in patients with functional dyspepsia (FD) and in healthy volunteers, and to investigate the association of alterations of electrogastrography with symptoms. Method: In 30 patients with FD and 12 healthy volunteers, the recording of electrogastrography with symptom assessments was performed preprandially and postprandially. Subjects ingested the same volume of water and a nutrient drink at a fixed rate, which was performed in a randomized cross‐over design. Results: Unlike water, the power ratio after/before a nutrient drink was significantly lower in patients compared to controls. Patients had more severe bloating and epigastric pain after nutrient ingestion than after water intake. Absent postprandial increase of power was observed in seven of the 30 patients after nutrient intake, and in three of the 30 patients after water intake. The former patients had significantly more severe fullness and bloating. Irrespective of a test meal, the percentage rates of normogastria significantly decreased postprandially in the patient group, but not in the control group. No differences in symptom severity were observed between patients with and without abnormally low percentage rates of normogastria. Conclusions: Decreased postprandial rates of normogastria and absent postprandial increase of power are electrogastrographic abnormalities found in a subset of patients with FD. A nutrient drink is more adequate for the detection of such alterations than water. The lack of a postprandial increase of power is associated with the severity of some dyspeptic symptoms, but decreased postprandial rates of normogastria are not.     

Intestinointestinal Inhibitory Reflexes

The motor response induced by intraluminal distension of the small intestine has been well investigated. However, little is known of the myoelectrical response to intraluminal distension. The aim of this study was to investigate the effects of oral- and anal-side distension on jejunal slow waves in dogs. The study was performed in 10 healthy female hound dogs implanted with three pairs of electrodes on the jejunum and an intestinal fistula. The first study session was designed to investigate the effects of anal-side distension on jejunal myoelectrical activity in fasting state. The protocol consisted of a 30-min baseline recording, a 30-min recording during anal-side balloon distension located 5 cm distal to the most distal pair of electrodes, and another 30-min recording after distension. The second session was designed to investigate the effect of oral-side distension with the balloon 5 cm proximal to the most proximal pair of electrodes. Jejunal slow waves were severely impaired by both anal- and oral-side distension. The dominant power was significantly reduced from –2.96 ± 0.90 dB at baseline to –6.00 ± 0.64 dB during anal-side distension (P < 0.0005) and from –3.90 ± 0.85 dB at baseline to –7.17 ± 0.90 dB during oral-side distension (P < 0.001). The percentage of normal 17 to 22-cpm slow waves was significantly decreased from 97.39 ± 0.88% to 83.48 ± 3.12% during anal-side distension (P < 0.0005) and from 92.49 ± 2.42% to 68.80 ± 7.24% during oral-side distension (P < 0.002). The percentage of slow wave coupling was decreased from 95.08 ± 2.27% to 52.48 ± 7.73% during anal-side distension (P < 0.0005) and from 84.82 ± 6.75% to 49.21 ± 8.91% during oral-side distension (P < 0.001). The instability coefficient of the dominant frequency was significantly increased during anal-side distension. In conclusion, intraluminal distension of the jejunum severely impairs jejunal slow waves. The slow waves on both sides of distension become less coupled, less regular, and are of lower amplitude.     

Gastric myoelectrical and motor abnormalities in children and adolescents with functional recurrent abdominal pain

Background and Aims: Recurrent abdominal pain is common among children and adolescents. The majority of the affected patients have no apparent cause for their symptoms. This study evaluated gastric myoelectrical activity and motility abnormalities in children and adolescents with functional recurrent abdominal pain. Methods: Forty‐two children with functional recurrent abdominal pain [19 (45.2%) males, mean 8 years, SD 3 years, 19 functional abdominal pain, 9 irritable bowel syndrome, 9 functional dyspepsia, 1 abdominal migraine, 1 aerophagia and 3 non‐specific abdominal pain according to Rome III criteria] and 20 healthy children [10 (50%) males, mean 9 years, SD 2.7 years] from the same geographical area underwent electrogastrography (EGG), and ultrasonographic assessment of gastric emptying rate and antral motility. Results: Average gastric emptying rate, amplitude of antral contractions and antral motility index were lower in patients (46.5%, 74.3% and 6.5 respectively) compared to controls (66.17%, 89% and 8.3 respectively) (P < 0.001). Gastric emptying rate had a negative correlation with scores obtained for severity of symptoms (r = ?0.63, P < 0.0001). Postprandial dominant frequency instability co‐efficient (post‐DFIC) was higher in patients than in controls (27.83% vs 18.3%, P = 0.0087), and correlated with the symptom score (r = 0.26, P = 0.045). Conclusions: Gastric emptying and antral motility were significantly impaired in patients, indicating a possible role for gastric motility disturbances in the pathogenesis of childhood functional recurrent abdominal pain. Further studies, including therapeutic trials, are needed to confirm this association and for recommendation of prokinetic drugs in its management.     

Is There a One-to-One Correlation Between Gastric Emptying of Liquids and Gastric Myoelectrical or Motor Activity in Dogs?

The aim of this study was to investigate the correlation of gastric emptying with gastric myoelectrical activity recorded from internal serosal electrodes and with gastric motility measured from strain gauges. The study was performed in eight healthy dogs chronically implanted with four pairs of electrodes and two strain gauges on the gastric serosa and equipped with a duodenal fistula for the assessment of gastric emptying. Each dog was fed four liquid test meals on four separate days with identical calories (320 kcal) and volume (473 ml). A correlation was found between gastric emptying and the energy of contraction in the frequency band of 3.75–7.50 cycles/min during the first 30 min after the meal (r = 0.46, P < 0.05). While none of the parameters of gastric myoelectrical activity was correlated with gastric emptying, two major parameters, percentage of regular gastric slow waves and percentage of slow-wave coupling, were found to be associated with delayed gastric emptying. A significant correlation was found between the frequency of gastric slow waves and that of the contractions in both fasting (r = 0.83, P < 0.001) and fed state (r = 0.70, P < 0.001 at 30 min, r = 0.86, P < 0.001 at 60 min). It was concluded that gastric emptying is correlated with the strength of gastric contractions in a frequency range identical to that of the gastric slow waves, and there is no one-to-one correlation between gastric emptying of liquids and any parameters of gastric myoelectrical activity. However, major parameters of gastric myoelectrical activity are associated with gastric emptying.     

An improved electrogastrographic system in measuring myoelectrical parameters

This study assessed the reliability of an improved electrogastrographic (EGG) system in recording stomach myoelectrical parameters and tried to establish the normal ranges of myoelectricity using this system. The analytical software of the current system mainly included an autoregressive modelling program to compute myoelectrical frequency and power. Forty healthy subjects were enrolled to receive myoelectrical measurement in two consecutively fasting and one postprandial 30 min sessions. The myoelectrical frequencies in both fasting and postprandial sessions were almost three cycles per min (c.p.m.) and showed little variation. The percentage of dominant frequencies (2.5–3.5 c.p.m.) in three sessions was approximately 80% while the computed myoelectrical powers in the first and second fasting sessions exhibited a significant correlation ( r = 0.84, P < 0.001). Meal ingestion increased the myoelectrical powers by 6.8 dB compared with the second fasting recording ( P < 0.001). The mean variation in myoelectrical amplitude for the ratio of second: first fasting session was 110.3 ± 88.8% (16–478%, median 88%). This new EGG system is, indeed, reliable for measuring myoelectrical frequency and power, whereas the interassay of recorded amplitudes appears markedly variable.     

Gastric myoelectrical activity in patients with type I diabetes mellitus and autonomic neuropathy

In patients with diabetes mellitus and gastroparesis, dysrhythmias of gastric myoelectrical activity, especially tachygastrias, are thought to be involved in the pathogenesis of dyspeptic symptoms. Using surface electrogastrography we studied the prevalence of these abnormalities, and their relationships to dyspeptic symptoms and the extent of cardiac autonomic neuropathy in 30 euglycemic patients with type I diabetes mellitus and 12 controls. Neither in the fasting nor in the postprandial state were differences in mean frequency of gastric electrical control activity and its variability found between patients and controls. In the fasting state, the power content of the 3 cpm component in the power spectrum of the electrogastrogram was even higher in patients than in controls (P=0.049). In the fasting state, second harmonics of the 3 cpm fundamental gastric signal were seen more often in patients than in controls (P=0.03). In patients with symptoms during the study, no second harmonics were found after the meal. The postprandial/fasting power ratio was decreased in patients with symptoms during the study as compared to patients without symptoms and controls (P<0.05). The incidence of dysrhythmias, such as tachygastrias and bradygastrias, was not higher in patients than in controls (17% and 8%, respectively). No correlation was found between electrogastrographic parameters and the severity of autonomic neuropathy or dyspeptic symptoms scored before the study. In conclusion, this study has shown that patients with type I diabetes mellitus and autonomic neuropathy studied under euglycemic conditions do not have grossly disturbed myoelectrical activity, except when symptomatic during the study.Supported by the Dutch Diabetic Foundation.     

Correlation between gastric myoelectrical activity recorded by multi-channel electrogastrography and gastric emptying in patients with functional dyspepsia

Objective. To investigate the correlation between the parameters of multi-channel electrogastrography (MEGG) and gastric emptying in patients with functional dyspepsia. Material and methods. The MEGG study included 19 patients with functional dyspepsia and 19 healthy subjects. MEGG was recorded for 30?min in the fasting state and 60?min after a standard test meal (450?kcal). MEGG parameters included the power ratio (PR), the normal percentage of 2–4?cpm gastric slow waves (N%) and the percentage of slow wave coupling (%SWC). Gastric emptying was measured in the 19 patients by SPECT (single photon emission computerized tomography) and the gastric emptying parameters included lag phase (LP), half time of gastric emptying (T1/2), emptying rate of stable phase (ERSP), one hour retention rate (1HRR), and two hour retention rate (2HRR). Results. No significant difference in MEGG parameters was found between normal subjects and patients. There was a significant negative correlation between postprandial N% and LP (r=???0.52, p<0.05) and a significant negative correlation between fasting %SWC and 1HRR (r=???0.48, p<0.04) or 2HRR (r=???0.48, p<0.05). Compared with the patients in the PR?>?1 group, patients in the PR?≤?1 group had significantly higher T1/2 and 2HRR but lower ERSP. Conclusions. Both the temporal regularity and spatial regularity of gastric slow waves have negative correlations with gastric emptying, which suggests that the impaired gastric myoelectrical activity may be responsible for the delayed gastric emptying in patients with functional dyspepsia.     

胃起搏对胃动力紊乱犬胃排空及胃肌电活动的影响

目的　研究胃起搏对胃动力紊乱犬胃排空及胃电参数的影响。方法　采用双侧迷走神经干切断术联合应用胰高血糖素建立胃动力紊乱犬模型 ;采用 4导联胃肠电系统微机分析仪记录胃肠浆膜肌电活动 ;99mTc 植酸钠标记的半固体试餐 ,单光子计算机断层显像技术 (SPECT)检测胃半排空时间(GEt1/ 2 ) ;采用适宜起搏参数从胃体、胃窦在腹部投影部位输入起搏信号驱动胃电节律。结果　迷走神经干切断术后犬的GEt1/ 2 为 (79.4 2± 1.91)min ,较术前 (5 6 .35± 2 .99)min明显延迟 (P <0 .0 0 1) ,但行胃起搏治疗后GEt1/ 2 为 (6 4 .94± 1.75 )min ,较治疗前明显加快 (P <0 .0 0 1) ;胃起搏治疗前迷走神经干切断犬餐后的胃电频率为 (0 .0 81± 0 .0 0 7)Hz、胃电幅度为 (2 .32± 0 .35 )mV、慢波的传播速度为 (4 .0 6± 0 .4 0 )cm/s ,均较正常对照犬显著降低 [(0 .0 90± 0 .0 0 6 )Hz ,(4 .2 5± 0 .12 )mV ,(6 .92± 0 .2 4 )cm/s,(P <0 .0 5 ) ],治疗后其餐后胃电频率 (0 .0 92± 0 .0 0 5 )Hz、胃电幅度 (3.97± 0 .19)mV和慢波的传播速度 (5 .5 7± 0 .4 8)cm/s均明显高于治疗前 (P <0 .0 5 )。结论　采用适宜起搏参数输入起搏信号可完全触发胃电慢波 ,改善胃电参数 ,纠正药物导致的异常胃电节律 ,加速胃排空 ,恢     

Postprandial Response of Gastric Slow Waves: Correlation of Serosal Recordings with the Electrogastrogram

Controversial interpretations have been given to the postprandial increase in the dominant power (amplitude) of the electrogastrogram (EGG). The aim of this study was to find an appropriate interpretation of the postprandial EGG power changes. Simultaneous serosal and cutaneous recordings of gastric myoelectrical activity were made in 11 patients with gastroparesis in the fasting state and after the ingestion of 8 oz of water. The dominant frequency and corresponding power of the recording before and after water were computed using the power spectral analysis method. It was found that the dominant frequency of the EGG was the same as that of the serosal recording in 10 patients. One patient showed a substantial amount of dysrhythmia and no obvious dominant frequency was noted. A decrease in the dominant frequency was found in these 10 patients after the ingestion of water. Tachygastria of higher than 4 cycles/min was observed in one of 11 patients both in the prewater and postwater states. Consistent changes in amplitude after a drink of water were noted in both serosal recording and EGG. Statistical analysis demonstrated that the dominant power change after water computed from the EGG was correlated with that observed in the serosal recording (r = 0.757, P = 0.007). In conclusion, exogenous stimulation, such as ingestion of water, may change the amplitude of the gastric slow wave and this change is reflected in the EGG, suggesting that the change of the slow-wave amplitude is an important contributing factor to the postprandial change in the EGG dominant power.