Gastric dysrhythmias and nausea of pregnancy

Gastric dysrhythmias have been recorded from patients with a variety of nausea syndromes. The aim of this study was to measure gastric myoelectric activity in women with and without nausea during the first trimester of pregnancy. In 32 pregnant women gastric myoeletric activity was recorded for 30-45 min with cutaneous electrodes that yielded electrogastrograms (EGGs). Frequencies of the EGG waves were analyzed visually and by computer. Subjects rated their nausea at the time of EGG recording on a visual analog scale with 0 representing no nausea and 300 mm severe nausea. Gastric dysrhythmias were found in 26 pregnant subject: Seventeen had tachygastrias (EGG frequencies of 4-9 cpm), five had 1- to 2-cpm EGG waves, and four had flat-line patterns Mean nausea scores of the subjects with tachygastrias, 1- to 2-cpm, and flat-line patterns were 64.8 +/- 13, 93.4 +/- 23, and 77.2 +/- 36, respectively. Six pregnant subjects had normal 3-cpm EGG patterns, and their nausea scores averaged 2.8 +/- 1.1 (P less than 0.05 compared with nausea scores in subjects with tachygastrias, 1- to 2-cpm, and flat-line rhythms). Six subjects with gastric dysrhythmias during pregnancy were restudied after delivery; each of these subjects had normal 3-cpm EGG patterns and none had nausea. Thus, gastric dysrhythmias are objective pathophysiologic events associated with symptoms of nausea reported during the first trimester of pregnancy.     

Gastric dysrhythmias following pylorus-preserving pancreaticoduodenectomy

Transient delayed gastric emptying is reported as a frequent complication following pancreas-preserving pancreaticoduodenectomy (PPW). We placed serosal electrodes on the stomach of a patient undergoing PPW. Myoelectric recordings were obtained postoperatively and correlated with simultaneous radionuclide liquid gastric emptying studies. The patient developed early postoperative gastric atony, associated with frequent gastric dysrhythmias. These dysrhythmias may have been exacerbated by a perihepatic abscess. The gastric dysrhythmias correlated with alterations in liquid gastric emptying. Gastric dysrhythmias may be a mechanism for gastric dysfunction in the early postoperative period.This work was supported by the Medical Research Service of the VA Medical Center, Gainesville, Florida.     

Gastric antral dysrhythmias in children with chronic idiopathic intestinal pseudoobstruction.

Chronic idiopathic intestinal pseudoobstruction is a serious disorder of intestinal neuromuscular function resulting in recurrent episodes of intestinal obstruction, and is caused by primary disease of the enteric nerves or enteric smooth muscle. Gastric electrical control activity detected by the non-invasive technique of surface electrogastrography was investigated in 11 children (0.1-16 years) with proven chronic idiopathic intestinal pseudoobstruction (four with known disease of the enteric nerves, three with disease of smooth muscle cells, and four without defined pathology), to determine whether abnormalities were present and whether these were useful in detecting the underlying pathology. Abnormalities were present in eight of 11 patients. Persistent tachygastria (electrical control activity frequency > 5 cycles/minute) was found in three patients, all with a proven neuropathy. A continuously irregular frequency was found in five patients, three with a proven myopathy and two with undefined pathology. A normal electrical control activity frequency was present in three patients, one with a proven neuropathy and two with undefined pathology. It is suggested that this non-invasive technique may provide a useful screening test of the pathophysiological basis of the functional obstruction in children with chronic idiopathic intestinal pseudoobstruction.     

Obesity and dysrhythmias

In the United States, obesity has reached epidemic proportions. Results from the 2003-2004 National Health and Nutrition Examination Survey estimated that 66% of US adults are either overweight (body mass index [BMI] 25-30 kg/m(2)) or obese (BMI>30 kg/m(2)) as defined by the BMI cutoffs established by the World Health Organization. In the 1970s, only 15% of the US population between the ages of 20 and 74 years was categorized as obese. In 2003, approximately 32% of the adult population was obese. Obesity plays an important role in the evolution of cardiovascular disease. This article reviews the histopathophysiologic changes that occur in cardiac structure and function in response to obesity, explores the relationship between obesity and arrhythmias such as atrial fibrillation and sudden cardiac death, and analyzes electrocardiographic changes in an obese patient.     

Gastric electrical stimulation with short pulses reduces vomiting but not dysrhythmias in dogs

BACKGROUND & AIMS: The aim of this study was to investigate the acute effects of 3 different methods of electrical stimulation in the prevention of vasopressin-induced emetic response and gastric dysrhythmias. METHODS: Seven female hound dogs chronically implanted with 4 pairs of electrodes on gastric serosa were used in a 5-session study. Saline and vasopressin were infused in sessions 1 and 2, respectively. In the other 3 sessions with vasopressin infusion, 3 different methods of electrical stimulation (short-pulse stimulation, long-pulse stimulation, and electroacupuncture) were applied. Gastric slow waves and vomiting and behaviors suggestive of nausea were recorded in each session. In a separate study, additional experiments were performed in 5 vagotomized dogs to investigate vagally mediated mechanisms. RESULTS: Vasopressin induced gastric dysrhythmias, uncoupling of slow waves, and vomiting and behaviors suggestive of nausea (P < 0.02, analysis of variance). Long-pulse stimulation, but not short-pulse stimulation or electroacupuncture, was capable of preventing vasopressin-induced gastric dysrhythmias and gastric slow wave uncoupling. Short-pulse stimulation and electroacupuncture, but not long-pulse stimulation, prevented vomiting and significantly reduced the symptom scores, which was not noted in the dogs with truncal vagotomy. CONCLUSIONS: Long-pulse stimulation normalizes vasopressin-induced slow wave abnormalities with no improvement in vomiting and behaviors suggestive of nausea. Short-pulse stimulation and electroacupuncture prevent vomiting and behaviors suggestive of nausea induced by vasopressin but have no effects on slow waves, and their effects are vagally mediated.     

Clinical value of electrogastrography and the gastric emptying test

OBJECTIVE : To: (i) assess the clinical value of electrogastrography (EGG) and the gastric emptying test; and (ii) investigate the relationship between gastric myoelectrical activity and gastric emptying (GE). METHODS : One hundred and forty patients with functional dyspepsia (FD), 30 patients with non‐insulin‐dependent diabetes mellitus (NIDDM) and 20 healthy volunteers were studied. Gastric myoelectrical activity was recorded by using cutaneous EGG. The gastric emptying time was measured by using isotopic, radiopaque marker (Rom’s) and ultrasound methods. RESULTS : The dysrhythmia rates in patients with NIDDM were 70.0% (21/30) before meals and 66.7% (20/30) after meals, and the tachygastria rates of these patients were 36.7% before meals and 33.3% after meals. In NIDDM patients, the dominant frequency (DF) after meals (2.60 ± 0.30 cycles per minute; c.p.m.), the fed DF/fasting DF ratio (1.01 ± 0.11), the dominant power (DP) after meals (121.45 ± 67.00 V² c.p.m.) and the fed DP and fasting DP ratios (0.81 ± 0.07) were significantly lower than those in normal controls (P < 0.05 or P < 0.01). The DP after meals in patients with FD (210.60 ± 68.40 V² c.p.m.) was significantly lower than that in normal controls (P < 0.01). Delayed gastric emptying was more common in patients with FD and NIDDM. The rate of delayed gastric emptying in 121 cases with normal myoelectrical rhythm was 39.7% (48/121). In 69 cases with dysrhythmia, 45.9% (17/37) with bradygastria and 78.1% (25/32) with tachygastria had delayed gastric emptying. CONCLUSIONS : Electrogastrography and the gastric emptying test are feasible methods for evaluating gastric myoelectrical activity and gastric motility. The precise relationship between gastric myoelectrical activity and gastric motility has not been proven, but there is a close relationship between tachygastria and delayed gastric emptying.     

Use of electrogastrography in children

Electrogastrography (EGG), the measurement of gastric pacemeaker activity by means of surface electrodes, provides a noninvasive technique to detect and quantify the characteristics of the gastric slow wave. With a predominant frequency of three cycles per minute, the activity of the specialized cells responsible for this pacing, the interstitial cells of Cajal, is crucial in providing the underlying electrophysiologic changes that enable coordinated smooth muscle contraction and synchronized peristalsis. Advances in electronics and software to define frequency distribution, stability of the signal, postprandial changes, and other parameters have contributed to more widespread interest in EGG and its application to the investigation of functional gastrointestinal disturbances. Definition of pediatric norms and postnatal changes in the EGG of premature infants has provided the foundation for further studies investigating correlative changes with such important functions as gastric emptying and motility. The EGG remains a promising diagnostic tool. Future studies will help define its usefulness in identifying abnormal functions of the interstitial cells of Cajal.     

The problem of ventricular dysrhythmias and sudden death mortality in heart failure: the impact of current therapy

Congestive heart failure (CHF), one of the few cardiovascular conditions increasing in incidence and prevalence, is characterized by high morbidity and mortality. Up to 50% of the mortality is attributable to dysrhythmic sudden death. Risk stratification to identify those most susceptible to sudden death remains imperfect. The advances in CHF therapeutics and management over the past 16 years have had a favorable impact on CHF mortality including sudden death. The role of amiodarone and implantable cardioverter-defibrillator intervention is evolving and discussed in the context of current CHF management and available trials.     

Gastric dysrhythmias occur in gastro-oesophageal reflux disease complicated by food regurgitation but not in uncomplicated reflux

AIM: To investigate gastric pacemaker activity in gastro-oesophageal reflux disease using the electrogastrogram. PATIENTS: Forty patients with gastro-oesophageal reflux disease (20 with acid reflux, 20 with the additional symptom of food regurgitation) and 30 asymptomatic controls. METHODS: Patients were studied using an electrogastrogram, oesophageal manometry, and 24 hour ambulatory oesophageal pH analysis. RESULTS: An abnormal electrogastrogram was recorded in two (7%) controls, two (10%) patients with acid reflux, and 10 (50%) patients with food regurgitation. Food regurgitators had significantly more gastric dysrhythmias (tachygastrias) both before (p<0.02) and after (p<0.01) a test meal. Gastric pacemaker activity was also significantly less stable following the test meal in food regurgitators (p<0.003). Patients with food regurgitation and an abnormal electrogastrogram had higher oesophageal acid exposure than those with a normal electrogastrogram (p<0.05). CONCLUSIONS: The electrogastrogram is usually normal in gastro-oesophageal reflux disease but an abnormal rhythm occurred in half of our patients with the additional symptom of food regurgitation. Furthermore, an abnormal electrogastrogram is associated with increased oesophageal acid exposure.     

肺移植的近况及展望

近年来随着肺移植基础研究领域的不断发展,在临床应用也日渐广泛,现就肺移植研究的基本状况综述如下。     

Microsporidiosis: current status

PURPOSE OF REVIEW: Microsporidiosis is an emerging and opportunistic infection associated with a wide range of clinical syndromes in humans. This review highlights the research on microsporidiosis in humans during the previous 2 years. RECENT FINDINGS: The reduced and compact microsporidian genome has generated much interest for better understanding the evolution of these parasites, and comparative molecular phylogenetic studies continue to support a relationship between the microsporidia and fungi. Through increased awareness and improved diagnostics, microsporidiosis has been identified in a broader range of human populations that, in addition to persons with HIV infection, includes travelers, children, organ transplant recipients, and the elderly. SUMMARY: Effective commercial therapies for Enterocytozoon bieneusi, the most common microsporidian species identified in humans, are still lacking, making the need to develop tissue culture and small animal models increasingly urgent. Environmental transport modeling and disinfection strategies are being addressed for improving water safety. Questions still exist about whether microsporidia infections remain persistent in asymptomatic immune-competent individuals, reactivate during conditions of immune compromise, or may be transmitted to others at risk, such as during pregnancy or through organ donation. Reliable serological diagnostic methods are needed to supplement polymerase chain reaction or histochemistry when spore shedding may be sporadic.