Development of gastric slow waves and effects of feeding in pre-term and full-term infants

The aims of this study were to investigate the difference in developmental process of gastric slow waves and the effects of feeding in pre-term and full-term infants. Twenty-six pre-term and 31 full-term infants were enrolled in the study. Gastric myoelectrical activity was recorded using electrogastrography (EGG) from birth to month 6. An increase in the % of 2-4 cpm slow waves was noted in both pre-term (P < 0.01) and full-term infants (P < 0.04) from birth to month 4. The pre-term infants showed a reduced dominant EGG power at certain points of the study. (3) Breast or formula feeding resulted in no difference in the EGG in the full-term infants and showed a difference in the postprandial dominant power of the EGG in the pre-term infants only at month 2 after birth (P < 0.05) but not at other times. The gastric slow wave in pre-term infants is of a significantly reduced amplitude but similar rhythmicity. The method of feeding has no effects on the EGG in full-term infants and minimal effects (may be of non-clinical significance) on the EGG in pre-term infants as the difference was noted only at one time point during the 6-month follow-up study.     

Effects of electroacupuncture on gastric myoelectrical activity in healthy humans

The acupuncture point of the wrists (PC6) and the lower legs (ST36) are common points for the treatment of gastric symptoms. However, it remains unclear whether these two acupoints have different effects on gastric myoelectrical activity. We compared the effect of electroacupuncture (EAP) between PC6 and ST36 on gastric myoelectrical activity using surface electrogastrography (EGG). EAP (1 Hz, for 30 min) was applied at either ST36, or PC6, or both acupoints in eight healthy volunteers. EAP at both PC6 and ST36 did not change the percentage of normal slow waves and tachygastria. While EAP at either PC6 or ST36 did not change period dominant frequency (PDF), EAP at both PC6 and ST36 significantly decreased PDF to 78.1 +/- 8.4% of baselines. EAP at PC6 reduced period dominant power (PDP) to 47.2 +/- 5.3% of baselines, while EAP at ST36 increased PDP to 153.6 +/- 28.3% of baselines. EAP at shoulders (sham acupuncture) did not affect the gastric myoelectrical activity. EAP at either PC6 or ST36 shows an opposite effect on PDP, whereas EAP at both PC6 and ST36 has a synergistic effect on PDF. Understanding site-specific effects of acupuncture may contribute to the selection of appropriate acupoints for treating functional GI disorders.     

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

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

Electrogastrographic power ratio in humans is not related to changes in antrum-skin distance but to antral motility

It is not clear whether the power increase in electrogastrography (EGG) after meal or water ingestion reflects increases in gastric motility or gastric distension bringing the stomach closer to the electrodes on the abdominal skin surface. We recorded EGG and real-time ultrasonography simultaneously before and after 150-ml water ingestion in 17 healthy volunteers. We calculated gastric power, by spectral analysis of EGG by the maximum entropy method, for 400 s before and after water ingestion, and calculated their ratio (power ratio). We calculated, using sonography, the number of antral contractions before and after water ingestion, the motility index after water ingestion, the distance between the antrum and the abdominal skin surface before and after water ingestion, and the ratio of these distances (distance ratio). The number of contractions was positively correlated with gastric power before water ingestion, and the antrum-skin distance was negatively correlated with gastric power both before and after water ingestion. The motility index after water ingestion was positively correlated with both gastric power after water ingestion (Spearman's rank correlation r = 0.492; P = 0.0498) and the power ratio (r = 0.615; P = 0.0141). There was no correlation between the distance ratio and the power ratio. These results suggest that the power increase in EGG induced by water ingestion does not reflect the approach of the antrum to the abdominal surface, but rather, reflects antral motility after water ingestion. (Received June 16, 1997; accepted Nov. 28, 1997)     

婴儿期胃电慢波发育的研究

目的研究健康婴儿的胃电慢波发育。方法0～24个月健康婴儿，按3个月的年龄间隔分为9组，每组20例，其中男104例，女76例，无窒息，母乳喂养，无器质性疾病。采用体袁胃电图，分别于记录空腹和餐后体表胃电图各30min。计算出胃电慢波的以下参数：主频、不同慢波节律的百分比、主频不稳定系数、功率比。结果0,6、12、18和24个月健康婴儿餐前主频分别为（2．38&#177;0．5）、（2．54&#177;0．4）、（2．62&#177;0．3）、（2．86&#177;0．3）和（2．97&#177;0．2）cpm，餐后与餐前相比差异无显著性P〉0．05，正常胃电节律百分比分别为（38．6&#177;4．9）、（47．8&#177;3．4）、（55．6&#177;3．6）、（60．4&#177;3．7）、（69．7&#177;3．3），胃动过速节律百分比为（24．6&#177;5．4）、（18．6&#177;4．1）、（15．6&#177;4．9）、（14．7&#177;3．6）、（12．7&#177;4．3），胃动过缓节律百分比为（36．8&#177;5．5）、（33．6&#177;4．3）、（28．8&#177;3．8）、（24．9&#177;3．8）、（17．6&#177;3．7），18个月以上婴儿餐后正常胃电节律百分比较餐前升高（P〈0．05）。12个月以上婴儿餐前、餐后的主频不稳定系数降低（P〈0．05），餐后与餐前相比差异无显著性（P〉0．05），餐后餐前功率比12个月以上较12个月以下增加（P〈0．05）。结论婴儿期的胃电慢波经历一发育成熟阶段，正常胃电节律百分比和主频随年龄的增长逐渐升高，2岁时达到成人水平。     

Dalitong Granule(达立通颗粒)Combined with Electroacupuncture in the Treatment of Functional Dyspepsia:A Randomized Controlled Trial

Objective:To explore clinical short and long-term effect of combining Dalitong Granule(达立通颗料,DG) and electroacupuncture group(EA) in the treatment of functional dyspepsia.Methods:Totally 640 patients with confirmed functional dyspepsia were randomly divided into 4 groups using a randomized digital table:the DG group,the EA group,the combined group and the control group,160 cases in each group.The DG group was treated with 6 g DG 3 times daily;the EA group was treated with puncture of points Zusanli(ST36),Zhongwan(CV12),Neiguan(PC6),Taichong(LR3) and Gongsun(SP4) twice daily;the combined group with above-mentioned DG and EA;and the control group with 5 mg mosapride 3 times,20 mg pantoprazole and25 mg amitriptylines twice daily.The treatment course was 4 weeks for all groups.The symptom score,quality of life score by Short Form 36 Health Survey Questionnaires(SF-36),plasma motilin by radioimmunoassay,electrogastrographic frequencies by electrogastrogram(EGG) and gastric emptying by B-sonography were examined,and adverse reactions were observed before,at the end of treatment and 60 weeks post-treatment.Results:In the DG group 1 case dropped out for not taking medicine strictly and 1 case was lost to follow-up,while 1 case in the EA group and 2 cases in the combined therapy group were lost to follow-up.Compared with pre-treatment,quality of life score,plasma motilin,electrogastrographic frequencies and gastric emptying were all increased significantly,while symptom score was decreased significantly at the end of treatment in each group(P0.01);in the combined group quality of life score,plasma motilin,electrogastrographic frequencies and gastric emptying were all significantly higher than those in the other groups,while symptom score was significantly lower than in the other groups(P0.05).Compared with at the end of treatment,these indices changed insignificantly in the combined group and the EA group 60 weeks post-treatment(P0.05),but the 4increased indices were all decreased significantly,and symptom score was increased significantly in the DG and the control groups(P0.05).The short and long-term total effective rates in the combined group were all significantly higher than those in the other treatment groups(P0.05 or P0.01).No serious adverse reaction occurred in the four groups.Conclusion:Combined treatment of DG and EA could increase both plasma motilin and electrogastrographic frequencies,promote gastric emptying,alleviate the symptom of dyspepsia so as to increase quality of life,with better safety and long-term effect.     

Impaired circadian rhythm of gastric myoelectrical activity in patients with multiple system atrophy

Abstract In order to evaluate gastric motility and its circadian rhythm in patients with multiple system atrophy (MSA) and healthy control subjects, we measured gastric myoelectrical activity (GMA) for 24 hours using a cutaneous electrogastrogram (EGG) recorder in 14 MSA patients and 9 age-matched controls.We analyzed six 10-minute segments of EGG before and after each meal and two 20-minute EGG segments during sleep; three parameters were used for the analysis: dominant frequency (DF), instability coefficient of dominant frequency (ICDF), and dominant power (DP). DF increased during daytime and decreased during sleep in the control, while this circadian variation was blunted in the patients with MSA. The average DF of the eight segments in the MSA patients did not differ from that of the control. Both MSA patients and control subjects did not show the circadian variation of ICDF and DP. The average ICDF of the eight segments in the patients with MSA was significantly decreased when compared with that of the control (p<0.01). No differences were observed in DP between the two groups. This study indicates that the healthy subjects appear to have a circadian rhythm of DF, and the patients with MSA appear to have impaired circadian rhythm of DF and decreased ICDF possibly due to the degeneration of the central autonomic neurons.     

Recent progress in gastric arrhythmia: Pathophysiology,clinical significance and future horizons

Gastric arrhythmia continues to be of uncertain diagnostic and therapeutic significance. However, recent progress has been substantial, with technical advances, theoretical insights and experimental discoveries offering new translational opportunities. The discoveries that interstitial cells of Cajal (ICC) generate slow waves and that ICC defects are associated with dysmotility have reinvigorated gastric arrhythmia research. Increasing evidence now suggests that ICC depletion and damage, network disruption and channelopathies may lead to aberrant slow wave initiation and conduction. Histological and high‐resolution (HR) electrical mapping studies have now redefined the human ‘gastric conduction system’, providing an improved baseline for arrhythmia research. The application of HR mapping to arrhythmia has also generated important new insights into the spatiotemporal dynamics of arrhythmia onset and maintenance, resulting in the emergence of new provisional classification schemes. Meanwhile, the strong associations between gastric functional disorders and electrogastrography (EGG) abnormalities (e.g. in gastroparesis, unexplained nausea and vomiting and functional dyspepsia) continue to motivate deeper inquiries into the nature and causes of gastrointestinal arrhythmias. In future, technical progress in EGG methods, new HR mapping devices and software, wireless slow wave acquisition systems and improved gastric pacing devices may achieve validated applications in clinical practice. Neurohormonal factors in arrhythmogenesis also continue to be elucidated and a deepening understanding of these mechanisms may open opportunities for drug design for treating arrhythmias. However, for all translational goals, it remains to be seen whether arrhythmia can be corrected in a way that meaningfully improves organ function and symptoms in patients.     

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.