Abnormal cerebral processing of oesophageal stimuli in patients with noncardiac chest pain (NCCP)

Recent advances in the knowledge of the mechanism of reflux hypersensitivity

Reflux hypersensitivity (RH) is a subtype of gastroesophageal reflux disease. The Rome IV criteria separated RH from the original nonerosive reflux disease subgroup and classified it as a new functional oesophageal disease. Recently, the pathogenesis of RH has become the focus of research. According to the latest research reports, upregulation of acid-sensitive receptors, distribution of calcitonin gene-related peptide-positive nerve fibres, and psychiatric comorbidity have key roles in the pathogenesis of RH. This work reviews the latest findings regarding RH mechanisms.

Roles of Heart Rate Variability in Assessing Autonomic Nervous System in Functional Gastrointestinal Disorders: A Systematic Review

Functional gastrointestinal disorders (FGID) and gastroesophageal reflux (GERD) disease affect a large global population and incur substantial health care costs. Impairment in gut-brain communication is one of the main causes of these disorders. The central nervous system (CNS) provides its inputs to the enteric nervous system (ENS) by modulating the autonomic nervous system (ANS) to control the gastrointestinal functions. Therefore, GERD and FGID's might be associated with autonomic dysfunction, which can be identified via heart rate variability (HRV). FGIDs may be treated by restoring the autonomic dysfunction via neuromodulation. This article reviews the roles of HRV in the assessment of autonomic function and dysfunction in (i) gastroesophageal reflux (GERD), and the following FGIDs: (ii) functional dyspepsia (FD) and gastroparesis, (iii) irritable bowel syndrome (IBS) and (iv) constipation. The roles of HRV in the assessment of autonomic responses to various interventions were also reviewed. We used PUBMED, Web of Science, Elsevier/Science direct and Scopus to search the eligible studies for each disorder, which also included the keyword 'heart rate variability'. The retrieved studies were screened and filtered to identify the most suitable studies using HRV parameters to associate the autonomic function with any of the above disorders. Studies involving both human and animal models were included. Based on analyses of HRV, GERD as well as the FGIDs were found to be associated with decreased parasympathetic activity and increased sympathetic nervous system activity with the autonomic balance shifted towards the sympathetic nervous system. In addition, the HRV methods were also reported to be able to assess the autonomic responses to various interventions (mostly neuromodulation), typically the enhancement of parasympathetic activity. In summary, GERD and FGIDs are associated with impaired autonomic dysfunction, mainly due to suppressed vagal and overactive sympathetic tone, which can be assessed noninvasively using HRV.

Identifying and managing functional cardiac symptoms

Recurring chest pain and other cardiac symptoms that cannot be adequately explained by organic pathology are common and can be associated with substantial disability, distress and high healthcare costs. Common mental disorders such as depression and anxiety frequently co-occur with these symptoms and, in some cases, account for their presentation, although they are not universally present. Due to the frequency of functional cardiac presentations and risks of iatrogenic harm, physicians should be familiar with strategies to identify, assess and communicate with patients about these symptoms. A systematic and multidisciplinary approach to diagnosis and management is often needed. Health beliefs, concerns and any associated behaviours should be elicited and addressed throughout. Psychiatric comorbidities should be concurrently identified and treated. For those with persistent symptoms, psychosocial outcomes can be poor, highlighting the need for further research and investment in diagnostic and therapeutic approaches and multidisciplinary service models.

Marijuana: A systems-based primer of adverse effects associated with use and an overview of its therapeutic utility

Marijuana use is on the rise in the United States. By the end of 2019, 33 states have legalized marijuana use and marijuana byproduct use for medical purposes. However, marijuana use does not come without side effects. This manuscript reviews the increasing usage of marijuana and the different forms (natural and synthetic) that patients may use when presenting to clinicians. It also addresses the biochemical and behavioral changes observed with marijuana use, including the location and changes associated with cannabinoid receptors (abbreviated CB1 and CB2). These two topics lead into an extensive review of the side effects of marijuana use. This manuscript discusses gastrointestinal side-effects, such as Cannabinoid Hyperemesis Syndrome, pancreatitis, and hepatotoxicity. It also briefly reviews cardiovascular, neurologic, and pulmonary side effects. This article provides an overview of therapeutic effects of marijuana including the antiemetic effect, its medical utility as an appetite stimulant, and usefulness in cancer patients post-chemotherapy. A thorough social history pertaining to marijuana use is an important consideration for clinicians in patients presenting with a variety of symptoms, including those effecting the gastrointestinal, cardiovascular, pulmonary, or neurologic systems.

Esophageal disorders in patients with irritable bowel syndrome

Aim.To study the whole range of esophageal disorders in patients with irritable bowel syndrome (IBS) using high-tech methods. Materials and methods.102 IBS patients (47 males, mean age 40.8, diagnosis of IBS was established according to Rome III criteria) with esophageal symptoms (heartburn, belching, globus sensation and noncardiac chest pain) were examined in gastroenterology department. All patients underwent endoscopy, with biopsies if required, X-ray examination of upper gastrointestinal tract; 24-hour pH-impedance monitoring;13C-urea breath test. Evaluation of esophageal symptoms was carried out on the basis of Rome IV criteria. Results.21 (20.6%) individuals had esophagitis (ERD). According to 24-hour pH-monitoring data, 7 of them had overlap between GERD and functional esophageal disorders (FED). 27 (26.5%) individuals had nonerosive reflux disease (NERD). In 54 (52.9%) individuals endoscopy and pH-impedance monitoring data did not differ from normal, suggesting this group as group of patients with FED. There was no significant difference for age, sex and IBS subtypes in GERD, NERD and FED groups. Conclusion.Comorbid esophageal disorders in patients with IBS are different and represented by organic diseases, FED and overlap between them. Methods such as 24-h pH-impedance measurement and esophageal manometry should be used to assess comorbid esophageal disorders in IBS patients.

The Mexican consensus on non-cardiac chest pain

INTRODUCTION

Non-cardiac chest pain is defined as a clinical syndrome characterized by retrosternal pain similar to that of angina pectoris, but of non-cardiac origin and produced by esophageal, musculoskeletal, pulmonary, or psychiatric diseases.

AIM

To present a consensus review based on evidence regarding the definition, epidemiology, pathophysiology, and diagnosis of non-cardiac chest pain, as well as the therapeutic options for those patients.

METHODS

Three general coordinators carried out a literature review of all articles published in English and Spanish on the theme and formulated 38 initial statements, dividing them into 3 main categories: (i)definitions, epidemiology, and pathophysiology; (ii)diagnosis, and (iii)treatment. The statements underwent 3rounds of voting, utilizing the Delphi system. The final statements were those that reached >75% agreement, and they were rated utilizing the GRADE system.

RESULTS AND CONCLUSIONS

The final consensus included 29 statements. All patients presenting with chest pain should initially be evaluated by a cardiologist. The most common cause of non-cardiac chest pain is gastroesophageal reflux disease. If there are no alarm symptoms, the initial approach should be a therapeutic trial with a proton pump inhibitor for 2-4weeks. If dysphagia or alarm symptoms are present, endoscopy is recommended. High-resolution manometry is the best method for ruling out spastic motor disorders and achalasia and pH monitoring aids in demonstrating abnormal esophageal acid exposure. Treatment should be directed at the pathophysiologic mechanism. It can include proton pump inhibitors, neuromodulators and/or smooth muscle relaxants, psychologic intervention and/or cognitive therapy, and occasionally surgery or endoscopic therapy.

Effects of Shugan Hewei Granule on Depressive Behavior and Protein Expression Related to Visceral Sensitivity in a Rat Model of Nonerosive Reflux Disease

Objective

To explore the effect of Shugan Hewei Granule (SGHWG) and to provide the experimental basis for its clinical application.

Methods

40 healthy male Wistar rats were divided into 5 groups, with 8 rats in each group, including control group, model group, normal saline (NS) group, SGHWG group, and Rabeprazole group. The control group was not treated. The model group was treated with fructose intake and mental stress to be the model of NERD. The other groups were treated as the model group and then gavaged with the corresponding drugs. The pH value of lower third of esophagus, immobile time in tail suspension test, CRF protein expression in both hypothalamus and anterior cingulate cortex (ACC), and SP protein in esophageal mucosa in lower third of esophagus detected by immunofluorescence and NMDAR1 protein expression in spinal cord detected by immunohistochemistry of each group were compared.

Results

The pH values of both the SGHWG group and the Rabeprazole group were higher than that of the model group (P<0.01), but the Rabeprazole group increased more obviously. The immobile time of the SGHWG group was shorter than that of the model group (P<0.01) and the Rabeprazole group (P<0.05). The expression of the CRF in the hypothalamus and ACC, NMDAR1 in the spinal cord, and SP in the esophageal mucosa in lower third of esophagus of the SGHWG group decreased significantly, compared with the model group (P<0.01), and was obviously lower than that in the Rabeprazole group (P<0.05).

Conclusions

This study provided an evidence that SGHW formula was inferior to Rabeprazole in acid inhibition, but it might reduce the expression of CRF protein of hypothalamus and ACC, lower the levels of NMDAR1 in spinal dorsal horn and SP in esophageal mucosa in lower third of esophagus, and regulate depressive behavior simultaneously, related to the improvement of visceral hypersensitivity in rat model of NERD.

What Is the Future of Impedance Planimetry in Gastroenterology?

The gastrointestinal (GI) tract is efficient in transporting ingested material to the site of delivery in healthy subjects. A fine balance exists between peristaltic forces, the mixing and delivery of the contents, and sensory signaling. This fine balance is easily disturbed by diseases. It is mandatory to understand the pathophysiology to enhance our understanding of GI disorders. The inaccessibility and complex nervous innervation, geometry and mechanical function of the GI tract make mechanosensory evaluation difficult. Impedance planimetry is a distension technology that assesses luminal geometry, mechanical properties including muscle dynamics, and processing of nociceptive signals from the GI tract. Since standardized models do not exist for GI muscle function in vivo, models, concepts, and terminology must be borrowed from other medical fields such as cardiac mechanophysiology. The review highlights the impedance planimetric technology, muscle dynamics assessment, and 3 applied technologies of impedance planimetry. These technologies are the multimodal probes that assesses sensory function, the functional luminal imaging probe that dynamically measures the geometry of the lumen it distends, and Fecobionics that is a simulated feces providing high-resolution measurements during defecation. The advanced muscle analysis and 3 applied technologies can enhance the quality of future interdisciplinary research for gaining more knowledge about mechanical function, sensory-motor disorders, and symptoms. This is a step in the direction of individualized treatment for GI disorders based on diagnostic subtyping. There seems to be no better alternatives to impedance planimetry, but only the functional luminal imaging probe is currently commercially available. Wider use depends on commercialization of the multimodal probe and Fecobionics.

Spatiotemporal characteristics of the pharyngeal event-related potential in healthy subjects and older patients with oropharyngeal dysfunction

BACKGROUND

Oropharyngeal dysphagia (OD) is a highly prevalent symptom in older people. Appropriate oropharyngeal sensory feedback is essential for safe and efficient swallowing. However, pharyngeal sensitivity decreases with advancing age and could play a fundamental role in the physiopathology of swallowing dysfunction associated with aging. We aimed to characterize pharyngeal sensitivity and cortical response to a pharyngeal electrical stimulus in healthy volunteers (HV) and older patients with and without OD.

METHODS

Eight young HV, eight older HV without OD, and 14 older patients with OD were studied by electroencephalography through 32 scalp electrodes. Pharyngeal event-related potentials (ERP) were assessed following electrical stimulation of the pharynx. Sensory and tolerance thresholds to the electrical stimulus and latency, amplitude, and scalp current density of each ERP component were analyzed and compared. An ERP source localization study was also performed using the sLORETA software.

KEY RESULTS

Older participants (with and without OD) presented an increased sensory threshold to pharyngeal electrical stimulation (10.2 ± 1.7 mA and 11.5 ± 1.9 mA respectively), compared with young HV (6.0 ± 1.2 mA). The cortical activation of older HV in response to pharyngeal electrical stimulus was reduced compared with young HV (N2 amplitude: 0.22 ± 0.79 vs -3.10 ± 0.59, P<.05). Older patients with OD also presented disturbances to the pharyngo-cortical connection together with disrupted pattern of cortical activation.

CONCLUSIONS AND INFERENCES

Older people present a decline in pharyngeal sensory function, more severe in older patients with OD. This sensory impairment might be a critical pathophysiological element and a potential target for treatment of swallowing dysfunction in older patients.

Role of Mixed Reflux and Hypomotility with Delayed Reflux Clearance in Patients with Non-cardiac Chest Pain

Background/Aims

Gastroesophageal reflux disease (GERD) is the most common cause of non-cardiac chest pain (NCCP). Currently available data reveal a weak relationship between NCCP and dysmotility. Moreover, it is unclear why some refluxes are perceived as heartburn and others as NCCP. We aimed to evaluate the role of the reflux pattern and the esophageal motility in patients with NCCP.

Methods

Forty-eight patients with NCCP (Group 1) and 50 only typical GERD symptoms (Group 2) were included and underwent high-resolution manometry (HRM) and multichannel intraluminal impedance-pH monitoring.

Results

Impaired peristalsis was found in 60% of patients with NCCP and in 24% of patients with typical symptoms (P < 0.05). In patients belonging to Group 1, the majority of reflux episodes associated with chest pain were acid and mixed. The proportion of mixed refluxes was higher than that in Group 2. In Group 1, the reflux clearing time at 5, 9, and 15 cm, measured in reflux episodes associated to NCCP was longer than in reflux episodes associated to typical symptoms (mean ± 95% CI: 27.2 ± 5.6, 23.3 ± 4.4, and 14.6 ± 2.3 seconds vs 18.3 ± 3.5, 13.3 ± 2.2, and 11.1 ± 1.8 seconds; P < 0.01).

Conclusions

The presence of gas in the refluxate seems to be associated with NCCP. The impaired motility observed in NCCP patients may play a relevant role in delaying reflux clearing, hence increasing the time of contact between refluxate and esophageal mucosa.

Role of 5-HT1A receptor in insular cortex mediating stress - induced visceral sensory dysfunction

BACKGROUND

5-HT1A receptors (HTR1As) in the insular cortex are thought to be related with the generation of stress-induced functional gastrointestinal disorders (FGIDs), but its mechanism is not clear. Visceral hypersensitivity is one important pathophysiological mechanism of FGIDs. This study aimed to explore the role of HTR1As in mediating stress-induced visceral hypersensitivity and its mechanism in the insular cortex.

METHODS

Visceral hypersensitivity rat model was established by water avoidance stress (WAS) and the visceral sensitivity was measured by electromyogram. The activities of HTR1As were regulated by microinjecting the HTR1A agonist and antagonist into the insular cortex. The expression levels of 5-HT, HTR1A, N-methyl-d-aspartic acid receptor subtype 2B (NR2B) and c-fos were observed by RT-PCR, Western Blot and immunohistochemical staining.

KEY RESULTS

In WAS rats, the expression levels of 5-HT and HTR1As in the insular cortex were significantly lower (p < 0.05) than that in sham WAS and normal rats, but the levels of c-fos and NR2B were significantly higher (p < 0.05). After microinjecting HTR1As agonist into the insular cortex of WAS rats, the visceral sensitivity and the expression levels of NR2B and c-fos in insular cortex significantly decreased (p < 0.05).

CONCLUSIONS & INFERENCES

The HTR1As-NR2B signal pathway of insular cortex plays an important role in regulating stress-induced visceral hypersensitivity.

Functional Esophageal Disorders

Functional esophageal disorders consist of a disease category that present with esophageal symptoms (heartburn, chest pain, dysphagia, globus) not explained by mechanical obstruction (stricture, tumor, eosinophilic esophagitis), major motor disorders (achalasia, EGJ outflow obstruction, absent contractility, distal esophageal spasm, jackhammer esophagus), or gastroesophageal reflux disease (GERD). While mechanisms responsible are unclear, it is theorized that visceral hypersensitivity and hypervigilance play an important role in symptom generation, in the context of normal or borderline function. Treatments directed at improving borderline motor dysfunction or reducing reflux burden to sub-normal levels have limited success in symptom improvement. In contrast, strategies focused on modulating peripheral triggering and central perception are mechanistically viable and clinically meaningful. However, outcome data from these treatment options are limited. Future research needs to focus on understanding mechanisms underlying visceral hypersensitivity and hypervigilance so that appropriate targets and therapies can be developed.

Prevalence of Gastrointestinal Diseases and Treatment Status in Noncardiac Chest Pain Patients

Background and Objectives

We evaluated the prevalence of gastroesophageal reflux diseases (GERD) in noncardiac chest pain (NCCP) patients, risk factors for GERD, and status of prescriptions for GERD in Korean population.

Subjects and Methods

This was a retrospective non-interventional observational nation-wide 45-center study. Patients with a normal coronary angiogram (CAG) and upper gastroendoscopy within 2 years after CAG were enrolled. The prevalence of GERD was examined. Other gastrointestinal diseases including peptic ulcer diseases or gastritis were also examined. Risk factors for GERD were compared between the GERD group and non-GERD group. The ratio of patients medicated for gastrointestinal diseases (antacids or proton-pump inhibitor) was also examined.

Results

Nine hundred four patients were enrolled. Among the NCCP patients, GERD was present in 436 (48.2%), peptic ulcer disease in 154 patients (17.0%), and gastritis in 659 (72.9%). There was no difference in risk factors for GERD between the GERD and non-GERD patients. Medications for GERD and other gastrointestinal diseases were prescribed in 742 (82.1%) patients.

Conclusion

GERD was common (42.8%) in Korean NCCP patients and most (82.1%) received the prescription of gastrointestinal medications. No differences were evident in risk factors between GERD and non-GERD patients.

Do patients with functional chest pain have neuroplastic reorganization of the pain matrix? A diffusion tensor imaging study

Background and aims

In functional chest pain (FCP) of presumed esophageal origin central nervous system hyperexcitability is generally believed to play an important role in pain pathogenesis. However, this theory has recently been challenged. Using magnetic resonance diffusion tensor imaging, the aim was to characterize any microstructural reorganization of the pain neuromatrix in FCP patients.

Methods

13 FCP patients and 20 matched healthy controls were studied in a 3T MR scanner. Inclusion criteria were relevant chest pain, normal coronary angiogram and normal upper gastrointestinal evaluation. Apparent diffusion coefficient (ADC) (i.e. mean diffusivity of water) and fractional anisotropy (FA) (i.e. directionality of water diffusion as a measure of fiber organization) values were assessed in the secondary sensory cortex, cingulate cortex, insula, prefrontal cortex, and amygdala.

Results

Overall, including all regions, no difference in ADC and FA values was found between the patients and controls (P = 0.79 and P = 0.23, respectively). Post-hoc tests revealed no difference in ADC and FA values of the individual regions. However, a trend of patients having increased ADC in the mid insula grey matter and increased FA in the mid insula white matter was observed (both P = 0.065).

Conclusions

This explorative study suggests that microstructural reorganization of the central pain neuromatrix may not be present in well-characterized FCP patients.

Implications

This finding, together with recent neurophysiologal evidence, challenges the theory of visceral hypersensitivity due to changes in the central nervous system in FCP patients.

Central response to painful electrical esophageal stimulation in well-defined patients suffering from functional chest pain

BACKGROUND

Functional chest pain (FCP) of presumed esophageal origin is considered a common cause for chest pain in which central nervous system hyperexcitability is thought to play an important role. We aimed to compare cerebral responses with painful esophageal stimuli between FCP patients and healthy subjects (HS).

METHODS

Thirteen patients with FCP (seven females, mean age 50.4 ± 7.5 years) and 15 HS (eight females, mean age 49.1 ± 12.9 years) were enrolled. Inclusion criteria consisted of typical chest pain, normal coronary angiogram, and normal upper gastrointestinal evaluation. Electrical stimulations evoking the pain threshold were applied in the distal esophagus, while cortical evoked potentials were recorded from the scalp. Pain scores, resting electroencephalogram (EEG), evoked potential characteristics and brain electrical sources to pain stimulation were compared between groups.

KEY RESULTS

No differences were seen between patients and HS regarding (i) pain thresholds (patients: 20.1 ± 7.4 mA vs HS: 22.4 ± 8.3 mA, all P > 0.05), (ii) resting-EEG (P > 0.05), (iii) evoked brain potential latencies (N2: patients 181.7 ± 25.7 mS vs HS 182.2 ± 25.8 mS, all P > 0.05) and amplitudes (N2P2: patients 8.2 ± 7.2 μV vs HS: 10.1 ± 3.4 μV, all P > 0.05), (iv) topography (P > 0.05), and (v) brain source location (P > 0.05).

CONCLUSIONS & INFERENCES

No differences in activation of brain areas to painful esophageal stimulation were seen in this group of well characterized patients with FCP compared with sex- and age-matched HS. The mechanism of pain in FCP and whether it originates in the esophagus remains unsolved.

Effect of age and correlation between esophageal visceral chemosensitivity and mechanosensitivity in healthy Japanese subjects

BACKGROUND

The aim of this study was to examine the impact of age on esophageal sensation, and to determine whether esophageal mechanosensitivity and chemosensitivity are correlated in healthy Japanese subjects.

METHODS

To evaluate chemosensitivity, a catheter was inserted and placed 10 cm above the upper border of the lower esophageal sphincter (LES), which was determined with an esophageal manometric catheter. After saline had been infused into the esophagus at a rate of 10 mL/min for 2 min, 0.1 N hydrochloric acid, instead of saline-without the subjects' knowledge-was infused for 10 min at the same rate. The acid perfusion sensitivity score (APSS) was assessed. To evaluate mechanosensitivity, a barostat test was performed, with a balloon being placed 10 cm above the upper border of the LES. The initial perception threshold (IPT), pain threshold (PT), and maximal pain were quantified.

RESULTS

The APSS was significantly inversely correlated with age. IPT, PT, and mean maximal pain were significantly correlated with age. Body mass index, drinking, and smoking habits were not correlated with the esophageal perception threshold. The correlation of chemosensitivity and mechanosensitivity was also assessed, and the APSS was inversely correlated with IPT, PT, and maximal pain.

CONCLUSIONS

The thresholds of esophageal visceral chemosensitivity and mechanosensitivity in same individuals were significantly correlated and both of these thresholds were inversely correlated with age.

Selective serotonin reuptake inhibitors for the treatment of hypersensitive esophagus: a randomized, double-blind, placebo-controlled study

OBJECTIVES

Ambulatory 24-h pH-impedance monitoring can be used to assess the relationship of persistent symptoms and reflux episodes, despite proton pump inhibitor (PPI) therapy. Using this technique, we aimed to identify patients with hypersensitive esophagus and evaluate the effect of selective serotonin reuptake inhibitors (SSRIs) on their symptoms.

METHODS

Patients with normal endoscopy and typical reflux symptoms (heartburn, chest pain, and regurgitation), despite PPI therapy twice daily, underwent 24-h pH-impedance monitoring. Distal esophageal acid exposure (% time pH <4) was measured and reflux episodes were classified into acid or non-acid. A positive symptom index (SI) was declared if at least half of the symptom events were preceded by reflux episodes. Patients with a normal distal esophageal acid exposure time, but with a positive SI were classified as having hypersensitive esophagus and were randomized to receive citalopram 20 mg or placebo once daily for 6 months.

RESULTS

A total of 252 patients (150 females (59.5%); mean age 55 (range 18-75) years) underwent 24-h pH-impedance monitoring. Two hundred and nineteen patients (86.9%) recorded symptoms during the study day, while 105 (47.9%) of those had a positive SI (22 (20.95%) with acid, 5 (4.76%) with both acid and non-acid, and 78 (74.29%) with non-acid reflux). Among those 105 patients, 75 (71.4%) had normal distal esophageal acid exposure time and were randomized to receive citalopram 20 mg (group A, n=39) or placebo (group B, n=36). At the end of the follow-up period, 15 out of the 39 patients of group A (38.5%) and 24 out of the 36 patients of group B (66.7%) continue to report reflux symptoms (P=0.021).

CONCLUSIONS

Treatment with SSRIs is effective in a select group of patients with hypersensitive esophagus.

Comparison of central and intraesophageal factors between gastroesophageal reflux disease (GERD) patients and those with GERD-related noncardiac chest pain

Gastroesophageal reflux disease (GERD) causes a wide range of symptoms. Some patients present with typical symptoms such as heartburn and regurgitation and others with atypical symptoms such as chest pain. The mechanism responsible for the varying clinical presentation of GERD is still not fully elucidated. The aim of this study was to prospectively evaluate differences in central and local intraesophageal factors between patients with typical GERD symptoms and those with noncardiac chest pain (NCCP). Patients presenting with typical and atypical symptoms suspicious of GERD underwent upper endoscopy and 24-hour pH monitoring with four sensors, each positioned at a different esophageal level. All patients completed GERD symptom, Hospital Anxiety and Depression Scale, and Symptom Stress Rating questionnaires. From January 2006 to December 2009, 50 patients were recruited, 29 with typical symptoms, and 21 with NCCP. Patients with proven GERD and NCCP had higher proximal extension of acid during reflux episodes than patients with typical symptoms. They were found to be older, had a shorter history of symptom onset, worse anxiety scores, and more endoscopic findings compatible with gastritis. Proximal extension of acid during the reflux episodes in patients with GERD presenting with NCCP may play a role in symptom generation.

Brain responses to cardiac electrical stimulation: a new EEG method for evaluating cardiac sensation

Although cardiac sensation, such as palpitation or chest pain, is common and is sometimes a malignant sign of heart diseases, the mechanism by which the human brain responds to afferent signals from the heart remains unclear. In this study, we investigated whether electrical stimulation of the heart provokes brain responses in humans. We examined 15 patients (age: 65.4 ± 3.1 years old, 11 males and 4 females) implanted with either a cardiac pacemaker or cardiac resynchronization therapy (CRT) device. Electroencephalogram (EEG) was simultaneously recorded from the vertex during right ventricular pacing at 70-100 beats/min at baseline (1.5 V) and intense (6-8 V) stimulation sessions. We evaluated brain responses to cardiac electrical stimulation by measuring cerebral potentials that were obtained by subtracting the average of 100 EEG waves triggered by cardiac pacing during baseline stimulation from those during the intense stimulation. Intense stimulation of the cardiac pacemaker or CRT device reproducibly induced cardiac sensation in 6 out of the 15 patients; namely, the remaining 9 patients showed no reproducible response. Brain responses were evident by averaging cerebral potentials from all of the 15 patients and those from 6 patients with reproducible cardiac sensation. To the best our knowledge, this is the first report that demonstrates the brain responses to cardiac electrical stimulation in humans. This new method should be useful for examining pathophysiology of cardiac diseases with pathological cardiac sensation, including cardiac anxiety and silent myocardial ischemia.

Selective-serotonin reuptake inhibitors for the treatment of hypersensitive esophagus

In patients with proton-pump inhibitor (PPI) resistant reflux symptoms, ambulatory 24 h pH impedance monitoring can be used to assess whether a relationship exists between symptoms and reflux episodes. Using this technique it has been suggested that patients with typical reflux symptoms and a normal upper endoscopy should be subclassified as follows: normal endoscopy and abnormal distal acid esophageal exposure (patients with acid reflux); normal endoscopy, with normal distal acid esophageal exposure and a positive symptom association for either acid or nonacid reflux (patients with hypersensitive esophagus); and normal endoscopy, normal distal acid esophageal exposure and a negative symptom association for acid and nonacid reflux (patients with functional heartburn). Although for patients with a normal endoscopy and abnormal distal acid esophageal exposure more aggressive acid suppression can be recommended, managing patients with hypersensitive esophagus and functional heartburn remains a real challenge.Therefore, investigators have evaluated the role of tricyclic antidepressants or selective-serotonin reuptake inhibitors (SSRIs) in influencing esophageal perception. Imipramine has been shown to decrease pain perception in healthy male volunteers and improve symptoms of patients with chest pain and normal coronary angiograms. Trazodone improved symptoms in patients with esophageal contraction abnormalities, while administration of SSRIs lowered chemical and mechanical sensitivity and benefited patients with diffuse esophageal spasm. Furthermore, in a recent study conducted by our group, citalopram administered once daily for 6 months was effective in a select group of patients with hypersensitive esophagus, suggesting that there is a role for SSRIs in the treatment of this disorder.

The pain system in oesophageal disorders: mechanisms, clinical characteristics, and treatment

Pain is common in gastroenterology. This review aims at giving an overview of pain mechanisms, clinical features, and treatment options in oesophageal disorders. The oesophagus has sensory receptors specific for different stimuli. Painful stimuli are encoded by nociceptors and communicated via afferent nerves to the central nervous system. The pain stimulus is further processed and modulated in specific pain centres in the brain, which may undergo plastic alterations. Hence, tissue inflammation and long-term exposure to pain can cause sensitisation and hypersensitivity. Oesophageal sensitivity can be evaluated ,for example, with the oesophageal multimodal probe. Treatment should target the cause of the patient's symptoms. In gastro-oesophageal reflux diseases, proton pump inhibitors are the primary treatment option, surgery being reserved for patients with severe disease resistant to drug therapy. Functional oesophageal disorders are treated with analgesics, antidepressants, and psychological therapy. Lifestyle changes are another option with less documentation.

Distal esophageal hypercontractility is related to abnormal acid exposure

BACKGROUND AND AIMS

Nutcracker esophagus (NE) is a frequent primary motility disorder of the distal esophagus, and the relationship with acid exposure remains controversial. We studied simultaneous distal esophageal hypercontractility (EH) using two sensors at 8 and 3 cm above the lower sphincter (LES) and abnormal exposure to acid (pH DeMeester score).

METHODS

From 400 screened patients with chest pain and heartburn, 54 (age 44.5 ± 8.8 years and 74% females) had abnormal manometry and underwent acid exposure measurement. Frequencies of the EH disorder were classic NE (EH(3 cm)) found in 29 (40.8%) patients, diffuse (EH(3,8 cm)) in 30 patients (42.3%), and upper segmental (EH(8 cm)) in 12 patients (16.9%).

RESULTS

We found a positive correlation among age with high amplitude in EH(3 cm) and EH(3,8 cm). DeMeester's score (DMS) had the lowest value for EH(3,8 cm) (2.58 ± 0.23) compared with EH(8 cm) (3.78 ± 0.3, p <0.003) and EH(3 cm) (3.12 ± 0.2, p <0.06). Surface response for joint effect of age and DMS on amplitude at EH(3 cm) confirmed the highest amplitude was for older age and lower DMS.

CONCLUSIONS

EH(3 cm) and EH(3,8 cm) were common for esophageal motility and were inversely associated with DMS. Meanwhile, acid exposure was higher in younger patients and hypercontractility was more frequent in older subjects. The former group may benefit more from proton pump inhibitors and the latter from visceral analgesics or possibly both.

Noncardiac chest pain: epidemiology, natural course and pathogenesis

Noncardiac chest pain is defined as recurrent chest pain that is indistinguishable from ischemic heart pain after a reasonable workup has excluded a cardiac cause. Noncardiac chest pain is a prevalent disorder resulting in high healthcare utilization and significant work absenteeism. However, despite its chronic nature, noncardiac chest pain has no impact on patients' mortality. The main underlying mechanisms include gastroesophageal reflux, esophageal dysmotility and esophageal hypersensitivity. Gastroesophageal reflux disease is likely the most common cause of noncardiac chest pain. Esophageal dysmotility affects only the minority of noncardiac chest pain patients. Esophageal hypersensitivity may be present in non-GERD-related noncardiac chest pain patients regardless if esophageal dysmotility is present or absent. Psychological co-morbidities such as panic disorder, anxiety, and depression are also common in noncardiac chest pain patients and often modulate patients' perception of disease severity.

Proximal and distal esophageal sensitivity is decreased in patients with Barrett’s esophagus

AIM: To investigate sensations to multimodal pain stimulation in the metaplastic and normal parts of the esophagus in patients with Barrett’s esophagus (BE).

METHODS: Fifteen patients with BE and 15 age-matched healthy volunteers were subjected to mechanical, thermal and electrical pain stimuli of the esophagus. Both the metaplastic part and the normal part (4 and 14 cm, respectively, above the esophago-gastric junction) were examined. At sensory thresholds the stimulation intensity, referred pain areas, and evoked brain potentials were recorded.

RESULTS: Patients were hyposensitive to heat stimulation both in the metaplastic part [median stimulation time to reach the pain detection threshold: 15 (12-34) s vs 14 (6-23) s in controls; F = 4.5, P = 0.04] and the normal part of the esophagus [median 17 (6-32) s vs 13 (8-20) s in controls; F = 6.2, P = 0.02]. Furthermore, patients were hyposensitive in the metaplastic part of the esophagus to mechanical distension [median volume at moderate pain: 50 (20-50) mL vs 33 (13-50) mL in controls; F = 5.7, P = 0.02]. No indication of central nervous system abnormalities was present, as responses were comparable between groups to electrical pain stimuli in the metaplastic part [median current evoking moderate pain: 13 (6-26) mA vs 12 (9-24) mA in controls; F = 0.1, P = 0.7], and in the normal part of the esophagus [median current evoking moderate pain: 9 (6-16) mA, vs 11 (5-11) mA in controls; F = 3.4, P = 0.07]. Furthermore, no differences were seen for the referred pain areas (P-values all > 0.3) or latencies and amplitudes for the evoked brain potentials (P-values all > 0.1).

CONCLUSION: Patients with BE are hyposensitive both in the metaplastic and normal part of esophagus likely as a result of abnormalities affecting peripheral nerve pathways.

[Non-cardiac chest pain]

CONTEXT

Non-cardiac chest pain or functional chest pain is a syndrome with high prevalence in occidental world. Findings on 15%-30% of coronary angiograms performed in patients with chest pain are normal. Causes significant impact in quality of life of patients and is associated with increased use of the health care facilities.

DATA SOURCES

To this review the following data base were accessed: Medline, the Cochrane Library, LILACS. The limit was the last 5 years publications and were selected relevant original articles, reviews, consensus, guidelines and meta-analysis.

RESULTS

Forty-four papers were selected, 28 original articles, 12 reviews, 2 guidelines, 1 consensus and 1 meta-analysis.

CONCLUSIONS

Exclusion of cardiac disease is of crucial importance. On the other hand non-cardiac chest pain could be related to gastrointestinal, muscular and respiratory causes and/or psychological disturbances. Treatment aims to attack mechanism generator in order to relieve or to eliminate symptoms. Drugs are the cornerstone of treatment, exception to achalasia patients because those have better response to dilation of the esophagus or surgery, and to those who need intensive psychological therapy. The most important drugs used are proton pump inhibitors and tricyclic antidepressants, the latter, to modulate central signal process (visceral hypersensitivity) and autonomic response. Recently, new diagnostic facilities, and also therapeutic modalities, such as esophageal botulin toxin injection and hypnosis are under investigations. In the near future, maybe some of them would take a place in the therapeutic scenario of these patients.

Evaluation and management of patients with noncardiac chest pain

Up to a third of patients undergoing coronary angiography for angina-like chest pain are found to have normal coronary arteries and a substantial proportion of these individuals continue to consult and even attend emergency departments. Initially, these patients are usually seen by cardiologists but with accumulating evidence that the pain might have a gastrointestinal origin, it may be more appropriate for them to be cared for by the gastroenterologist once a cardiological cause has been excluded. This review covers the assessment and management of this challenging condition, which includes a combination of education, reassurance, and pharmacotherapy. For the more refractory cases, behavioral treatments, such as cognitive behavioral therapy or hypnotherapy, may have to be considered.

Non-cardiac chest pain: prevalence of reflux disease and response to acid suppression in an Asian population

BACKGROUND

Gastroesophageal reflux disease is thought to be the commonest cause of 'non-cardiac chest pain'. The use of proton-pump inhibitors resulting in improvement in the chest pain symptom would support this causal association.

OBJECTIVES

To determine the prevalence of gastroesophageal reflux disease in non-cardiac chest pain and the response of chest pain to proton-pump inhibitor therapy.

METHODS

Patients with recurrent angina-like chest pain and normal coronary angiogram were recruited. The frequency and severity of chest pain were recorded. All patients underwent esophagogastroduodenoscopy and 48-h Bravo ambulatory pH monitoring before receiving rabeprazole 20 mg bd for 2 weeks.

RESULTS

The prevalence of gastroesophageal reflux disease was 66.7% (18/27). The improvement in chest pain score was significantly higher in reflux compared to non-reflux patients (P = 0.006). The proportion of patients with complete or marked/moderate improvement in chest pain symptoms were significantly higher in patients with reflux (15/18, 83.3%) compared to those without (1/9, 11.1%) (P < 0.001).

CONCLUSION

The prevalence of gastroesophageal reflux disease in patients with 'non-cardiac chest pain' was high. The response to treatment with proton-pump inhibitors in patients with reflux disease, but not in those without, underlined the critical role of acid reflux in a subset of patients with 'non-cardiac chest pain'.

New technologies to investigate the brain-gut axis

Functional gastrointestinal disorders are commonly encountered in clinical practice, and pain is their commonest presenting symptom. In addition, patients with these disorders often demonstrate a heightened sensitivity to experimental visceral stimulation, termed visceral pain hypersensitivity that is likely to be important in their pathophysiology. Knowledge of how the brain processes sensory information from visceral structures is still in its infancy. However, our understanding has been propelled by technological imaging advances such as functional Magnetic Resonance Imaging, Positron Emission Tomography, Magnetoencephalography, and Electroencephalography (EEG). Numerous human studies have non-invasively demonstrated the complexity involved in functional pain processing, and highlighted a number of subcortical and cortical regions involved. This review will focus on the neurophysiological pathways (primary afferents, spinal and supraspinal transmission), brain-imaging techniques and the influence of endogenous and psychological processes in healthy controls and patients suffering from functional gastrointestinal disorders. Special attention will be paid to the newer EEG source analysis techniques. Understanding the phenotypic differences that determine an individual’s response to injurious stimuli could be the key to understanding why some patients develop pain and hyperalgesia in response to inflammation/injury while others do not. For future studies, an integrated approach is required incorporating an individual’s psychological, autonomic, neuroendocrine, neurophysiological, and genetic profile to define phenotypic traits that may be at greater risk of developing sensitised states in response to gut inflammation or injury.

Noncardiac chest pain

Noncardiac chest pain (NCCP) affects approximately 1 quarter of the adult population in the United States. The pathophysiology of the disorder remains to be fully elucidated. Identified underlying mechanisms for esophageal pain include gastroesophageal reflux disease (GERD), esophageal dysmotility, and visceral hypersensitivity. Aggressive antireflux treatment has been the main therapeutic strategy for GERD-related NCCP. NCCP patients with or without spastic esophageal motor disorders are responsive to pain modulators. The value of botulinum toxin injection, endoscopic treatment for GERD, and antireflux surgery in alleviating NCCP symptoms is limited.

Intraesophageal chemicals enhance responsiveness of upper thoracic spinal neurons to mechanical stimulation of esophagus in rats

Esophageal hypersensitivity is one of the most common causes of noncardiac chest pain in patients. In this study, we investigated whether exposure of the esophagus to acid and other chemical irritants affected activity of thoracic spinal neurons responding to esophageal distension (ED) in rats. Extracellular potentials of single thoracic (T3) spinal neurons were recorded in pentobarbital sodium-anesthetized, -paralyzed, and -ventilated male rats. ED (0.2 or 0.4 ml, 20 s) was produced by water inflation of a latex balloon placed orally into the middle thoracic region of the esophagus. The chemicals were administered via a tube that was passed through the stomach and placed in the thoracic esophagus. To irritate the esophagus, 0.2 ml of HCl (0.01 N), bradykinin (10 microg/ml), or capsaicin (10 microg/ml) were injected for 1-2 min. Only neurons excited by ED were included in this study. Results showed that intraesophageal instillation of HCl, bradykinin, and capsaicin increased activity in 3/20 (15%), 7/25 (28%), and 9/20 (45%) neurons but enhanced excitatory responses to ED in 9/17 (53%), 8/15 (53%), and 7/11 (64%) of the remaining spinal neurons, respectively. Furthermore, intraesophageal chemicals were more likely to enhance the responsiveness of low-threshold neurons than high-threshold neurons to the esophageal mechanical stimulus. Normal saline (pH 7.4, 0.2 ml) or vehicle instilled in the esophagus did not significantly affect activity or ED responses of neurons. We conclude that enhanced responses of thoracic spinal neurons to ED by the chemically challenged esophagus may provide a possible pathophysiological basis for visceral hypersensitivity in patients with gastroesophageal reflux and/or esophagitis.

Gastroesophageal reflux disease: beyond mucosal injury

Emerging information on physiology and pathophysiology of gastroesophageal reflux disease raises the question of whether our thought process should go beyond mucosal injury and consider 2 parallel tracks that may cross each other at some time, but at other times they may indeed remain parallel, that is, neurally mediated effects of reflux events beyond the esophageal wall and inflammation mediated effect of reflux within the esophageal wall. In this process, intraesophageal events with and without causing mucosal injury may induce changes in the neural function on a temporary or long-term basis resulting in symptoms at different organs and various levels not completely in lock-step with esophageal mucosal injury. Emerging data also suggest the influence of liminal and subliminal esophageal acid exposure on cerebral cortical networks involved in motor function such as swallowing in addition to its effect on sensory centers. These observations suggest the existence of a more extensive influence of esophageal sensory input to the cerebral cortical processing mechanisms than previously thought and may provide new avenues for research in pathophysiology of reflux disease.

Pain in chronic pancreatitis: the role of reorganization in the central nervous system

BACKGROUND & AIMS

In various chronic pain conditions cortical reorganization seems to play a role in the manifestations. The aim of this study was to investigate cortical reorganization in patients with pain caused by chronic pancreatitis.

METHODS

Twelve healthy subjects and 10 patients with chronic pancreatitis were included. The esophagus, stomach, and duodenum were stimulated electrically at the pain threshold using a nasal endoscope. The electroencephalogram was recorded from 64 surface electrodes and event-related brain potentials (EPs) were obtained.

RESULTS

As compared with healthy subjects, the patient group showed decreased latencies of the early EP components (N1, P < .001; P1, P = .02), which is thought to reflect the exogenous brain pain processing specifically. Source analysis showed that the dipolar activities corresponding to the early EPs were located consistently in the bilateral insula, in the anterior cingulate gyrus, and in the bilateral secondary somatosensory area. The bilateral insular dipoles were localized more medial in the patient group than in the healthy subjects after stimulation of all 3 gut segments (P < .01). There also were changes in the cingulate cortex where the neuronal source was more posterior in patients than in controls to stimulation of the esophagus (P < .05).

CONCLUSIONS

The findings indicate that pain in chronic pancreatitis leads to changes in cortical projections of the nociceptive system. Such findings also have been described in somatic pain disorders, among them neuropathic pain. Taken together with the clinical data this suggests a neuropathic component in pancreatic pain, which may influence the approach to treatment.

Non-cardiac chest pain: an update

Non-cardiac chest pain (NCCP) is very common, affecting up to a quarter of the USA adult population. Recent studies have shown that the disorder has a profound impact on patient's quality of life and is associated with marked increase in utilization of healthcare resources. Non-cardiac chest pain is a heterogeneous disorder with gastrointestinal and non-gastrointestinal causes. After excluding a cardiac cause, most NCCP patients are treated by cardiologists or primary care physicians and only the minority are referred to a gastroenterologist for further work-up. Gastro-oesophageal reflux disease (GORD) is the most common cause for NCCP. The role of oesophageal dysmotility in NCCP has been discounted in recent years. However, visceral hyperalgesia has been shown to play an important role in symptom generation of non-GORD-related NCCP. The main therapeutic interventions in GORD-related NCCP patients are potent antireflux modalities and pain modulators in those with non-GORD-related NCCP.

Central sensitization in patients with non-cardiac chest pain: a clinical experimental study

OBJECTIVE

Patients with non-cardiac chest pain (NNCP) suffer from unexplained and often intractable pain which can pose a major clinical problem. The aim of this study was to investigate nociceptive processing in NNCP patients and their response to experimentally acid-induced oesophageal hyperalgesia using a multimodal stimulation protocol.

MATERIAL AND METHODS

Ten highly selected patients with NCCP (mean age 43 years, 1 M) were compared with an age- and gender-matched group of 20 healthy subjects. After preconditioning, the distal oesophagus was painfully distended with a balloon using "impedance planimetry". This method assesses the luminal cross-sectional area of the oesophagus based on the electrical impedance of the fluid inside the balloon. The baseline distensions were done before and after pharmacological relaxation of the smooth muscle with 20 mg butylscopolamine. After baseline distensions, a series of up to 10 mechanical stimuli was performed (temporal summation). The stimulations were repeated after sensitization of the oesophagus induced by acid perfusion. The sensory intensities were assessed during the stimulations and the referred pain area was mapped.

RESULTS

At baseline distensions, no differences were seen between patients and controls before and after relaxation of the smooth muscles. The patients tolerated fewer repeated distensions than controls (4.8+/-0.5 versus 9.1+/-0.9; p=0.04) and had an increased size of the referred pain areas to the mechanical stimulations (32.9+/-6.2 versus 64.9+/-18.3 cm2; p=0.01). After sensitization with acid, the patients developed hyperalgesia (p<0.001), whereas no significant changes were seen in controls.

CONCLUSIONS

NCCP patients showed facilitated central pain mechanisms (temporal summation and visceral hyperalgesia after sensitization). This could be used in the diagnosis and understanding of the symptoms in these patients.

Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy.

Functional esophageal disorders

Functional esophageal disorders represent processes accompanied by typical esophageal symptoms (heartburn, chest pain, dysphagia, globus) that are not explained by structural disorders, histopathology-based motor disturbances, or gastroesophageal reflux disease. Gastroesophageal reflux disease is the preferred diagnosis when reflux esophagitis or excessive esophageal acid exposure is present or when symptoms are closely related to acid reflux events or respond to antireflux therapy. A singular, well-defined pathogenetic mechanism is unavailable for any of these disorders; combinations of sensory and motor abnormalities involving both central and peripheral neural dysfunction have been invoked for some. Treatments remain empirical, although the efficacy of several interventions has been established in the case of functional chest pain. Management approaches that modulate central symptom perception or amplification often are required once local provoking factors (eg, noxious esophageal stimuli) have been eliminated. Future research directions include further determination of fundamental mechanisms responsible for symptoms, development of novel management strategies, and definition of the most cost-effective diagnostic and treatment approaches.

Characterization of cortical potentials evoked by oesophageal balloon distention and acid perfusion in patients with functional heartburn

Oesophageal visceral hypersensitivity is thought to be important in generating symptoms in functional heartburn (FH). However, the neurophysiological mechanisms involved are poorly understood. The aim of this study was to compare the characteristics of oesophageal cortical evoked potentials (CEPs) induced by balloon distension and acid perfusion in FH and controls. We studied 21 FH patients and 12 healthy volunteers. Oesophageal mechanical stimulation was performed using the specially constructed mechanical pump. CEPs were recorded using the 10-20 international system of electroencephalogram recording. Oesophageal distention elicited recognizable, reproducible and muti-peak CEPs. CEP latencies for N1, P1 and N2 components were significantly shorter (P = 0.016, P = 0.003 and P = 0.031, respectively) in FH than in controls before perfusion. Acid perfusion significantly decreased the latencies of N1, P1 and N2 (P = 0.022, P = 0.007 and P = 0.041, respectively) and significantly increased the amplitude of P1-N2 components (P = 0.020) in FH patients, but not in controls. In conclusion, cortical evoked potential responses evoked by oesophageal distention and acid perfusion were greater in FH than in controls, suggesting that dysfunction of visceral neural pathways and/or alterations in cortical processing may produce and mediate oesophageal hypersensitivity in FH. These findings provide the evidence that central sensitization contributes to the development and maintenance of oesophageal hypersensitivity.

Neurophysiologic assessment of esophageal sensory processing in noncardiac chest pain

BACKGROUND & AIMS

Esophageal hypersensitivity is thought to be important in the generation and maintenance of symptoms in noncardiac chest pain (NCCP). In this study, we explored the neurophysiologic basis of esophageal hypersensitivity in a cohort of NCCP patients.

METHODS

We studied 12 healthy controls (9 women; mean age, 37.1 +/- 8.7 y) and 32 NCCP patients (23 women; mean age, 47.2 +/- 10 y). All had esophageal manometry, esophageal evoked potentials to electrical stimulation, and NCCP patients had 24-hour ambulatory pH testing.

RESULTS

The NCCP patients had reduced pain thresholds (PT) (72.1 +/- 19.4 vs 54.2 +/- 23.6, P = .02) and increased P1 latencies (P1 = 105.5 +/- 11.1 vs 118.1 +/- 23.4, P = .02). Subanalysis showed that the NCCP group could be divided into 3 distinct phenotypic classifications. Group 1 had reduced pain thresholds in conjunction with normal/reduced latency P1 latencies (n = 9). Group 2 had reduced pain thresholds in conjunction with increased (>2.5 SD) P1 latencies (n = 7), and group 3 had normal pain thresholds in conjunction with either normal (n = 10) or increased (>2.5 SD, n = 3) P1 latencies.

CONCLUSIONS

Normal esophageal evoked potential latencies with reduced PT, as seen in group 1 patients, is indicative of enhanced afferent transmission and therefore increased esophageal afferent pathway sensitivity. Increased esophageal evoked potential latencies with reduced PT in group 2 patients implies normal afferent transmission to the cortex but heightened secondary cortical processing of this information, most likely owing to psychologic factors such as hypervigilance. This study shows that NCCP patients with esophageal hypersensitivity may be subclassified into distinct phenotypic subclasses based on sensory responsiveness and objective neurophysiologic profiles.

Chest pain from gastroesophageal reflux disease in patients with coronary artery disease

Management of patients with coronary artery disease is a major challenge for physicians, patients, and the healthcare system. Chest pain experienced by patients with coronary disease can be of noncardiac origin, and symptoms frequently related to gastroesophageal etiologies. The distal esophagus and the heart share a common afferent nerve supply, suggesting that location and radiation of perceived pain may be identical. In addition, there is substantial overlap between the prevalence of coronary disease and gastroesophageal reflux disease. Many physicians, including cardiologists, prescribe acid-reducing therapy to coronary patients. However, no prospective, randomized studies to date have evaluated the potential benefit of such treatments to prevent chest pain symptoms for these patients. We review the studies on noncardiac chest pain demonstrating reflux in patients with and without coronary disease. Also, the association of reflux with exertional chest pain and cardiac syndrome X is discussed. A rationale is presented for prevention of noncardiac chest pain in coronary patients, and the potential role of acid-suppressive therapy in managing these patients is discussed.

The pathophysiology of non-cardiac chest pain

Various underlying mechanisms have been described in patients with non-cardiac chest pain (NCCP). By far, gastroesophageal reflux disease (GERD) is the most common cause and thus requires initial attention when patients with NCCP are managed. Esophageal dysmotility can be demonstrated in 30% of the NCCP patients, but appears to play a very limited role in symptom generation. A significant number of patients with NCCP lack any evidence of GERD and have been consistently shown to have reduced perception thresholds for pain. Peripheral and/or central sensitization have been suggested to be responsible for visceral hypersensivity in NCCP patients. Further understanding of the underlying mechanisms for pain in patients with NCCP will likely improve our current therapeutic approach.

Chest pain in patients with cardiac and noncardiac disease

OBJECTIVE

To describe factors influencing chest pain expression in patients with cardiac or noncardiac disease.

METHODS

The authors conducted a case presentation and review of literature.

RESULTS

Causes of chest pain are diverse. Psychologic factors influence chest pain expression commonly in patients with or without cardiac disease.

CONCLUSIONS

Physicians and other therapists must be aware of psychologic influences on chest pain expression to provide optimal treatment to their patients.

Sensory testing of the esophagus

Originally, sensory testing of the esophagus included the acid perfusion test and the edrophonium test, which were developed to assess patients with non-cardiac chest pain. In the last 2 decades interest in functional esophageal disorders has increased and thus further understanding of the underlying mechanisms of esophageal pain required development of new sensory testing techniques. Balloon distension using a computerized electronic device, electrical stimulation and impedance planimetry have generated important information about esophageal sensory thresholds for pain in different disease states. Intraluminal ultrasonography has been used to determine the physiologic changes of the muscle wall of the esophagus during perception of typical esophageal symptoms. Central evaluation of patients undergoing esophageal stimulation has recently been introduced to assess cerebral activation in different esophageal disorders. However, many studies using esophageal sensory testing are afflicted with significant design flaws, making interpretation of the results very difficult. This is primarily due to lack of recognition of factors that can modulate esophageal sensation.