The Relationship of the Post-reflux Swallow-induced Peristaltic Wave Index and Esophageal Baseline Impedance with Gastroesophageal Reflux Disease Symptoms

A Non-Invasive Technique for Long-Term Monitoring of Gastroesophageal Reflux-A Pilot Study

Many people suffer from gastric or gastroesophageal reflux disorder (GERD) due to a malfunction of the cardia, the valve between the esophagus and the stomach. GERD is a syndrome caused by the ascent of gastric juices and bile from the stomach. This article proposes a non-invasive impedance measurement method and demonstrates the correlation between GERD and impedance variation between appropriately chosen points on the patient's chest. This method is presented as an alternative to the most widely accepted diagnostic techniques for reflux, such as pH-metry, pH-impedance measurement, and esophageal manometry, which are invasive because they use a probe that is inserted through a nostril and reaches down to the esophagus.

Reflux definitions in esophageal multi-channel intraluminal impedance

Aim

In this study, we aim to propose consensus-based interpretations to enhance both automatic, and manual analysis and then present our recommendations about reflux-related variables to enhance Multichannel Intraluminal (MII) measurements.

Background

Multichannel Intraluminal Impedance-pH (MII-pH) monitoring is the most sensible option to evaluate Gastroesophageal Reflux Disease (GERD), specifically for the patients with normal endoscopy findings, and persistent symptoms without response to Proton Pomp Inhibitor therapy. There were only a few studies on the interpretation of reflux events in MII tracings.

Methods

Several 200 episodes of reflux events were reviewed during several meetings in five steps, to discuss and categorize unresolved issues within existing interpretations, and propose technical principles for accurate characterization of reflux events.

Results

In this study, we show that baseline impedance is determined using a moving average procedure to the impedance data of each channel with a time window of 60 seconds based on this finding; a liquid reflux event is defined as a retrograde 50% drop in baseline impedance, gas reflux event is defined as a rapid increase in impedance greater than 5 kΩ, Mixed liquid-gas reflux is defined as gas reflux occurring immediately before or during liquid reflux.

Conclusion

The reliability of final diagnosis is significantly dependent on the accurate detection of reflux events, which is currently confronting technical limitations. A pathological reflux event propagates to at least three of the impedance sites, according to the literature. We think that taking three impedance locations into account might be too strict.

Progress in research of pathogenesis of refractory gastroesophageal reflux disease

Refractory gastroesophageal reflux disease (rGERD) is a common clinical disease with many pathogenic factors, complex mechanisms, and increasing incidence. At present, scholars believe that the pathogenesis of rGERD is closely related to intra- and extra-esophageal factors. Elucidating the mechanism of rGERD can contribute to the diagnosis and treatment of the disease. This paper summarizes the current progress in the research of the pathogenesis of rGERD, and puts forward our own thoughts and prospects for the disease, in order to provide ideas for the in-depth study of the pathogenesis of rGERD.

Applying Lyon Consensus criteria in the work-up of patients with proton pump inhibitory-refractory heartburn

BACKGROUND

A hierarchical approach for gastro-oesophageal reflux disease (GERD) diagnosis by impedance-pH monitoring was proposed by the Lyon Consensus, based on acid exposure time (AET) and supportive impedance metrics.

AIMS

To establish the clinical value of Lyon Consensus criteria in the work-up of patients with proton pump inhibitory (PPI)-refractory heartburn.

METHODS

Expert review of off-therapy impedance-pH tracings from unproven GERD patients with PPI-refractory heartburn prospectively evaluated at referral centers. Impedance metrics, namely total reflux episodes, postreflux swallow-induced peristaltic wave index, and mean nocturnal baseline impedance, were assessed. Expert review of on-therapy preoperative impedance-pH tracings from a separate cohort of surgically treated erosive/nonerosive GERD cases.

RESULTS

Off-therapy, normal, inconclusive, and abnormal AET was found in 59%, 17%, and 23% of 317 cases. Supportive evidence of GERD was provided by abnormal impedance metrics in up to 22% and 62% of cases in the normal and inconclusive AET groups, respectively. Adding the cases with inconclusive AET and abnormal impedance metrics to the abnormal AET group, a significant increase in GERD evidence was observed (from 23% to 37% of cases, p < 0.0002). At the on-therapy presurgical evaluation, abnormal/inconclusive AET and supraphysiological values of impedance metrics showed ongoing reflux in 21% and 90% of 96 cases, respectively (p < 0.00001); a relationship between on-therapy ongoing reflux and PPI-refractory heartburn was confirmed by the favorable surgical outcome at 3-year follow-up, 88% of cases being in persistent off-PPI heartburn remission.

CONCLUSIONS

Impedance-pH monitoring, off- and on-therapy, is of high clinical value in the work-up of patients with PPI-refractory heartburn.

Application of Lyon Consensus criteria for GORD diagnosis: evaluation of conventional and new impedance-pH parameters

OBJECTIVE

To validate Lyon Consensus criteria for diagnosing gastro-oesophageal reflux disease (GORD) by reflux monitoring.

DESIGN

Manual review of impedance-pH tracings from patients with proton pump inhibitor (PPI)-dependent heartburn, evaluated off PPI. Acid exposure time (AET) thresholds defined by the Lyon Consensus and impedance parameters were investigated, namely, total refluxes (TRs), postreflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI).

RESULTS

The study included 488 patients, 178 (36%) with normal (<4%) AET, 89 (18%) with inconclusive (4%-6%) AET and 221 (45%) with abnormal (>6%) AET, alongside with 70 healthy controls. At receiver operating characteristic analysis, area under curve was 0.89, 0.95 and 0.89 for TRs, PSPW index and MNBI, respectively, and threshold values were 40, 50% and 2000 Ω; the 4% physiological AET threshold defined by the Lyon Consensus showed 100% specificity but 63% sensitivity. The thresholds defined for impedance parameters were validated against AET by means of ordered logistic regression, being in concordance with the 4% AET threshold (OR 2.5 for TRs, 18.9 for PSPW index and 5.7 for MNBI). TRs positivity and concordant PSPW index/MNBI positivity were found in 80%-90% of patients in the abnormal AET group, in 73%-74% of cases in the inconclusive AET group and in 28%-40% of cases in the group with normal AET.

CONCLUSIONS

Our results show the overall validity of the Lyon Consensus approach to GORD diagnosis. Adding evaluation of impedance parameters, namely, TRs, PSPW index and MNBI to AET appraisal, substantially improves the diagnostic yield of reflux monitoring.

Low Mean Nocturnal Baseline Impedance is Associated With a Pathological Acid Exposure Time in Children

BACKGROUND

The baseline impedance (BI) and the mean nocturnal baseline impedance (MNBI) serve as markers of mucosal integrity in patients with pathologic acid exposure time (AET). This work aims to investigate the association between the BI and MNBI with the AET in children.

METHODOLOGY

A retrospective study was performed in children ≤18 years old with suspicion of gastroesophageal reflux disease who underwent both endoscopy and pH-impedance monitoring (pH-MII). Esophagitis was graded according to the Los Angeles classification. The pathological AET was determined depending on the age (≥5% in patients >1 year and ≥10% in those ages ≤1 year). For the BI, 60 s measurements were taken every 4 h, and for the MNBI, 3 10 min measurements were taken between 1.00 and 3:00 am; then, they were averaged. The means of BI and MNBI were compared with each other, with the AET, and other variables.

RESULTS

Sixty-eight patients were included, 25% of patients presented pathological AET. The mean of the MNBI was higher than BI in channels 6 (2195 vs 1997 Ω, P = 0.011) and 5 (2393 vs 2228 Ω, P = 0.013). BI and MNBI at channel 6 were lower in patients with pathological AET than in those with normal AET (1573 vs 2138 Ω, P = 0.007) and (1592 vs 2396 Ω, P = 0.004), respectively.

CONCLUSIONS

Children with pathological AET had lower impedance values than those with normal AET. BI and MNBI measurements should be part of the routine MII-pH assessment in children.

Cervicogenic dysphagia associated with cervical spondylosis: A case report and brief review

Dysphagia (swallowing difficulty) is most often related to another health problems, including brain or spinal cord injury, neurological damage, neuromuscular disorders, and anatomical conditions. Dysphagia can have detrimental effects on pulmonary health and also impact nutritional intake. The right treatment depends on the cause established. Cervicogenic dysphagia is a cervical cause of difficulty in swallowing. This report describes a 53-year-old female patient with sore throat, swallowing difficulty for solids, and acid reflux for 2 years. Radiographs revealed anterior osteophytic lipping and kyphosis of the cervical spine and thoracolumbar (right convex) scoliosis. After 6 months of chiropractic treatment, her complaints and spinal deformity were obviously resolved. Our case report is unique in that the patient had an unusual presentation, i.e. cervical osteophytes, cervical kyphosis, and thoracolumbar scoliosis, which are all contributable causes of dysphagia. Correction of spinal deformity could result in positive treatment outcomes in selected patients with symptoms of cervicogenic dysphagia.

Post-reflux swallow-induced peristaltic wave is impaired in laryngopharyngeal and gastro-oesophageal reflux disease

INTRODUCTION

Laryngopharyngeal reflux (LPR) and gastro-oesophageal reflux disease (GORD) result from the reflux of gastric contents. The post-reflux swallow-induced peristaltic wave (PSPW) is an oesophageal reflex that facilitates chemical clearance of gastric contents following reflux events. PSPW index is a novel parameter that has been validated in assessing the effectiveness of chemical clearance in GORD, but not in LPR. This study aimed to assess chemical clearance in LPR and GORD by measuring PSPW indices in a consecutive series of patients.

METHODS

Reviewers blindly analysed off-therapy impedance-pH tracings from 187 patients clinically categorized as LPR (n = 105) or GORD (n = 82) by predominant symptom profile. Conventional impedance-pH measures and PSPW indices were analysed.

RESULTS

Mean PSPW index in the LPR group was higher than in the GORD group (39.7% (±17.7%) vs. 20.6% (±13.4%); p < 0.001). Abnormally low PSPW index (<61%) was seen in 85 (81%) of the LPR group, and 80 (97.6%) of the GORD group (p < 0.001). Area under the ROC curve for PSPW index to diagnose LPR was 0.83 (95% CI: 0.767-0.889; p < 0.001).

CONCLUSION

Post-reflux swallow-induced peristaltic wave was impaired in patients with LPR as well as oesophageal GORD, indicating an abnormality of chemical clearance following a reflux episode in both groups. PSPW index was more severely impaired in gastro-oesophageal reflux disease (GORD). The present study shows PSPW index is useful in the diagnosis of both LPR and GORD and exposes an abnormality of clearance of the oesophagus.

Correlation Between QTc Dispersion and Soluble Growth-stimulating Gene 2 Protein on the Early Prognosis of Acute Carbon Monoxide Poisoning Heart Disease

ABSTRACT

This study aimed to explore the correlation between QTc dispersion (QTcd) and soluble growth-stimulating gene 2 protein (sST2) after heart rate correction in patients with acute carbon monoxide poisoning heart disease. Among the 150 patients, 35 cases had severe toxic heart disease. The concentrations of sST2, cardiac troponin I, and creatine kinase-MB in the severe group began to increase from admission, 24 hours, and 2 days, respectively, and their detected values were all higher than those in the nonsevere group and the normal control group. There were statistically significant differences in sST2 and QTcd between the poisoning, nonsevere, and normal control groups before the treatment. There was a statistically significant difference between the indexes of the poisoning groups at different degrees 2 and 3 days after poisoning. Receiver operating characteristic curve analysis confirmed the sensitivity and specificity of sST2 and QTcd. The correlation analysis showed that sST2 and QTcd levels were positively correlated with the incidence of severe heart disease at admission. Generally, the combined observation of sST2 and QTcd improved the prediction sensitivity and were early predictor indexes of toxic heart disease.

Influence of gastric morphology on gastroesophageal reflux in adults: An observational study

The study's aim was to determine if there was an association between gastric morphology and gastroesophageal reflux (GER). Few published studies have investigated the relationship between gastric morphology and the risk of GER.A total of 777 patients were randomly selected from 3000 to 3300 patients who presented at a medical center in Taipei for annual health checkups from early 2008 through to late 2010 and underwent a series of radiographs of the upper gastrointestinal tract (UGI). GER was recorded during the real-time fluoroscopic study. Thirty-nine participants had a follow-up endoscopy, and another 164 participants were followed up by a second UGI series 12 +/ -1.5 months later, from late 2008 through to early 2022. All participants completed a lifestyle and symptom questionnaire. The variables included current smoking and alcohol consumption. Participants who had heartburn and dysphagia were included in the study. Additionally, all participants underwent a limited physical examination which recorded age, sex, body mass index, and total cholesterol and triglyceride levels.All participants were classified into types 1 to 6 based on the gastric morphology determined from the first UGI. Cascade stomach is recognized by characteristic findings on UGI. Gastric types 2 and 3 tend to appear as cascade stomachs and were significantly associated with GER (P < .05) compared with the other groups. Morphologic type 5 appeared as an elongated sac extending downward into the pelvic cavity and was less likely to develop GER (P < .001). The results of follow-up studies by UGI and endoscopy were similar to those of the first UGI. Gastric morphologic type 2 was significantly associated, and type 5 was usually not associated, with GER and erosive esophagitis (P < .05) compared with the other groups, by both UGI and endoscopy.Gastric morphologic types 2 and 3, with cascade stomach, might provide a relatively easy method for the development of the GER phenomenon. Gastric morphologic type 5 appeared as an elongated sac that might reduce the incidence of the GER phenomenon. The study suggested that gastric morphologic type could influence the occurrence of GER.

Characteristics of symptomatic belching in patients with belching disorder and patients who exhibit gastroesophageal reflux disease with belching

Background/Aims

Belching disorder (BD) is clinically distinct from gastroesophageal reflux disease (GERD) with belching. Supragastric belching (SGB) is closely associated with reflux episodes. This study investigates belch characteristics in association with reflux, compared between patients with BD and those who had GERD with belching.

Methods

Impedance pH monitoring data from 10 patients with BD and 10 patients with GERD who exhibited belching were retrospectively analyzed. Belches were considered "isolated" or "reflux-related" and acidic/non-acidic. Belch characteristics were compared between patients with BD and those with GERD.

Results

Symptomatic belches were more frequent in patients with BD than in patients with GERD (median, 160.5 vs 56.0, P < 0.05). SGB was the most common type in both groups; common subtypes comprised "isolated" in patients with BD and "isolated during the reflux period" in patients with GERD. Reflux-related SGB was more common in patients with GERD than in BD (78.3% vs 45.2%, P < 0.005). Both "preceding belching" including the reflux period and acidic SGB were more common in patients with GERD than in BD (31.8% vs 8.6% and 38.1% vs 8.9%, both P < 0.05). Supragastric belch number positively correlated with all reflux episodes in patients with GERD (adjusted R² = 0.572, P = 0.007).

Conclusions

BD is characterized by more belching, compared to GERD. SGB is more frequently associated with reflux in GERD than in BD; acidity may be related to GERD. In BD, SGB is typically non-acidic and unrelated to reflux. Distinct SGB characteristics may reflect different pathogenic mechanisms of reflux and associated symptoms.

Factors of Reflux Episodes With Post-reflux Swallow-induced Peristaltic Wave in Gastroesophageal Reflux Disease

Background/Aims

It is known that post-reflux swallow-induced peristaltic wave (PSPW) index represents the chemical clearance of the esophagus. However, few studies have explored why some reflux episodes could induce PSPW while others in the same patient could not. The purpose of this study is to investigate the characteristics of reflux episodes which could elicit PSPW.

Methods

In this study, 269 reflux episodes were detected, of which 90 with a PSPW and 179 without a PSPW. Comparisons were made between the characteristics of reflux episodes with a PSPW and without a PSPW. The characteristics were including nadir pH, pH drop, proximal extent (cm, sec), ascending velocity (cm/sec), volume clearance time, acid clearance time, percentage acidic (%), 15 to 60-minute acid burden (seconds), and 15- to 60-minute volume burden (seconds). The characteristics between the 2 groups were compared through performing Wilcoxon signed rank test.

Results

Reflux episodes followed by a PSPW were significantly associated with a higher proximal extent than those without a PSPW. After the reflux episodes, higher volume clearance time and larger volume burden were more likely to trigger a PSPW. However, there were no significant differences between the 2 groups in nadir pH, pH drop, ascending velocity, acid clearance time, percentage acidic, or acid burden.

Conclusions

The role of acid seems to be less important in a reflux episode inducing a PSPW. Proximal reflux episodes are more likely to induce a PSPW. The depression of volume clearance may also be an important factor in eliciting a PSPW.

Minor esophageal functional disorders: are they relevant?

PURPOSE OF REVIEW

High resolution esophageal manometry (HRM) has expanded understanding of esophageal motor function. The Chicago Classification scheme has allowed systematic categorization of the myriad of manometric parameters identified during HRM. Multichannel intraluminal impedance pH has enhanced ambulatory reflux monitoring through complete assessment of esophageal content transit. However, the clinical implications of identified minor esophageal functional disorders remain unclear.

RECENT FINDINGS

Esophagogastric junction outlet obstruction is defined by esophagogastric junction obstruction with preserved peristalsis and may be managed expectantly, or in a manner similar to achalasia. Hypercontractile esophagus has been associated with dysphagia and non-cardiac chest pain, but the clinical significance is unclear as a majority of patients will improve without specific therapy. Additionally, these findings may be confounded by chronic opiate use. Ineffective esophageal motility is characterized by diminished esophageal contraction amplitude, potentially causing dysphagia and GERD. However, this is commonly identified in asymptomatic volunteers and may represent a normal variant. The multiple rapid swallow sequence can assess esophageal contraction reserve, which may predict post fundoplication dysphagia. The post-swallow induced peristaltic wave can serve as a surrogate of gastric refluxate clearance, providing important prognostic value. However, the associated time burden and lack of alternative therapeutic options limit its clinical utility.

SUMMARY

Minor esophageal functional disorders provide new therapeutic targets for symptomatic patients. However, these findings have inconsistent associations with symptoms and poorly defined therapeutic options. Minor esophageal function disorders should not be interpreted in isolation, with management decisions accounting for clinical, endoscopic, and radiographic factors in addition.

Relationship between night reflux and sleep disturbance in elderly patients with gastroesophageal reflux disease in a tertiary hospital

BACKGROUND

The reflux symptoms of gastroesophageal reflux disease (GERD) seriously affect the quality of life of patients. Daytime reflux is obvious, but the duration of reflux is short, which has little impact on the quality of life. Although the frequency of nocturnal regurgitation is low, its duration is long, which seriously affects the sleep quality of patients. Therefore, GERD nocturnal regurgitation has become one of clinical research hotspots and an important problem to be solved.

AIM

To observe the relationship between night reflux and sleep disturbance in elderly patients with GERD in a tertiary hospital.

METHODS

Two hundred and forty elderly patients with gastroesophageal reflux admitted to the Second Jinhua Hospital of Zhejiang Province from February 2017 to August 2019 were selected as subjects for investigation of the incidence of nocturnal reflux symptoms, manifestations of sleep disorders, and the relationship between nocturnal reflux and sleep disorders.

RESULTS

Of 240 cases of GERD included, 36 (15.0%) had no nocturnal reflux and 204 (85.0%) had. In the past 1 mo, nocturnal reflux developed on average once a week or less in 34 (16.67%) of 204 patients with nocturnal reflux, twice a week in 78 (38.24%), and > 2 times in 52 (25.49%). Of 36 cases without nocturnal reflux symptoms, 9 (25.0%) had a sleep disorder, while all 204 (100.0%) cases with nocturnal reflux suffered from a sleep disorder. The incidence of sleep disorder was significantly higher in patients with nocturnal reflux than in those without (P < 0.05). Approximately 77.94% of the patients had decreased sleep quality. Daytime residual effect was found in 70.10% of patients. Sleep latency was prolonged in 55.88% of patients. When the latency was prolonged, the time to sleep was mainly 30-40 min. The total sleep time was shortened in 53.92% of patients, most of whom had a sleep time of 4-5 h. Among the 204 GERD patients, 106 (51.96%) needed drug therapy for nocturnal reflux, including 36 (33.96%) patients taking rabeprazole orally, 20 (18.87%) taking omeprazole orally, 30 (28.30%) taking cimetidine orally, and 20 (18.87%) taking sleeping pills orally, with an effective rate of 96.23% (102/106).

CONCLUSION

Nocturnal reflux may be one of the reasons affecting sleep disorders in elderly GERD patients. Proton pump inhibitor therapy can be administered in clinical practice.

Role of Reflux in the Pathogenesis of Eosinophilic Esophagitis: Comprehensive Appraisal With Off- and On PPI Impedance-pH Monitoring

OBJECTIVES

Role of reflux and mechanisms of response to proton pump inhibitor (PPI) therapy in eosinophilic esophagitis (EoE) have not yet been fully elucidated. Comprehensive assessment by impedance-pH monitoring could clarify these issues.

METHODS

Prospective multicenter study comparing EoE patients with healthy controls and gastroesophageal reflux disease cases. Patients with EoE were evaluated off- and on PPI; responsiveness was assessed by histology. Impedance-pH appraisal included chemical clearance, assessed with the postreflux swallow-induced peristaltic wave (PSPW) index, and mucosal integrity measured with mean nocturnal baseline impedance (MNBI).

RESULTS

Sixty consecutive patients with EoE were compared with 60 age- and sex-matched healthy controls and 60 subjects with gastroesophageal reflux disease. The number of total refluxes was higher, while the PSPW index was lower in patients with EoE than in healthy controls. Off PPI, a lower MNBI gradient between the mid and distal esophagus distinguished 20 patients with PPI-refractory EoE from 40 patients with PPI-responsive EoE and was a predictor of PPI failure. On PPI, a lower PSPW index was the sole reflux parameter distinguishing PPI-refractory from PPI-responsive EoE; all reflux parameters improved in PPI-responsive patients, whereas the PSPW index was not modified in PPI-refractory cases and was independently associated with PPI-responsiveness. MNBI in the distal and mid esophagus improved much more in PPI-responsive than in PPI-refractory EoE.

DISCUSSION

Reflux plays a role in the pathogenesis of EoE, more relevant in PPI-responsive cases. Low impedance gradient between the mid and distal esophagus may be useful to predict PPI refractoriness. PPIs mainly act by improving chemical clearance, i.e., by an antireflux action supporting long-term prescription in PPI-responsive EoE.

Differences in salivary secretory function between patients with erosive esophagitis and those with nonerosive reflux disease

BACKGROUND AND AIM

It has been speculated that impaired salivary flow contributes to abnormal acid clearance in patients with erosive esophagitis (EE). For easy and objective assessment of salivary function, we developed a salivary gland blood flow measurement technique using continuous-wave Doppler sonography. In the present study, we evaluated the salivary secretory function in patients with EE and those with nonerosive reflux disease (NERD) using this method.

METHODS

Doppler waveform analysis was performed on the facial artery to assess blood inflow to the submandibular gland of 30 healthy subjects (HS). Blood flow was compared before and after secretory stimulation with 1 mL of lemon juice. Saliva was simultaneously collected and weighed before and after stimulation. Continuous-wave Doppler sonography was also performed in patients with EE and NERD. The size of the submandibular gland was compared in 26 patients with EE, 41 patients with NERD, and 86 HS.

RESULTS

The submandibular gland blood flow increased after stimulation in all HS. Both within-day and day-to-day reproducibility were good. There was a significant correlation between the percent increase in the maximum velocity and the percent increase in salivary secretion. Although the size of the submandibular gland was not significantly different among the three groups, the percent increase in the maximum velocity in patients with EE was significantly smaller than that in HS.

CONCLUSIONS

We have established an easy method of assessing salivary function in daily practice. This study revealed that a decrease in salivary secretory function is involved in the pathology of EE.

Gastro-Esophageal Reflux in Children

Gastro-esophageal reflux (GER) is common in infants and children and has a varied clinical presentation: from infants with innocent regurgitation to infants and children with severe esophageal and extra-esophageal complications that define pathological gastro-esophageal reflux disease (GERD). Although the pathophysiology is similar to that of adults, symptoms of GERD in infants and children are often distinct from classic ones such as heartburn. The passage of gastric contents into the esophagus is a normal phenomenon occurring many times a day both in adults and children, but, in infants, several factors contribute to exacerbate this phenomenon, including a liquid milk-based diet, recumbent position and both structural and functional immaturity of the gastro-esophageal junction. This article focuses on the presentation, diagnosis and treatment of GERD that occurs in infants and children, based on available and current guidelines.

Impedance-pH Monitoring for Diagnosis of Reflux Disease: New Perspectives

Heartburn is the most specific symptom of gastroesophageal reflux disease (GERD). In clinical practice, heartburn relief by a proton pump inhibitor (PPI) trial does suffice to confirm GERD. However, an objective diagnosis of GERD is required before anti-reflux endoscopic or surgical interventions, independently from PPI response. Thus, since normal findings at upper endoscopy are detected in the majority of patients with heartburn, reflux monitoring is often required. When traditional catheter-based or wireless pH tests are used, reflux episodes are conventionally identified by pH drops below 4.0 units. Combined impedance-pH monitoring has the advantage to provide a comprehensive assessment of both physical and chemical properties of refluxate and the distinction between acid and weakly acidic refluxes, both proven to cause heartburn. Unfortunately, the conventional impedance-pH parameters, namely acid exposure time and number of reflux events, are characterized by suboptimal diagnostic sensitivity, and the reliability of symptom-reflux association indexes remains questionable. Therefore, novel impedance parameters, namely the post-reflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI), have recently been proposed in order to achieve a better diagnostic yield. In fact, they proved to be highly accurate in distinguishing reflux-related from reflux-unrelated heartburn, off- as well as on-PPI therapy. Currently, manual review of impedance-pH tracings is needed because of the modest accuracy of available software tools for automated analysis. PSPW index and MNBI are highly applicable and reproducible, and their calculation requires a few additional minutes during the manual review of impedance-pH tracings. So far, we believe that PSPW index and MNBI are ready for prime time and should become part of the standard analysis of impedance-pH tracings for GERD diagnosis in patients with endoscopy-negative heartburn.