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Background Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration. Aims The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue. Methods and results Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar circular mapping catheter (Lasso-map), and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We analyzed 25 patients (72% men, age 68 ± 15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 and 2.21 mV, respectively. Conclusion When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters.

BackgroundBipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration. The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four different catheters and to identify their specific LA cutoffs for scar and healthy tissue.MethodsConsecutive high-resolution electroanatomic mapping was performed using a multipolar Orion catheter (Orion-map), a duo-decapolar variable circular mapping catheter (Lasso-Map) and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3×3×3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1 mV, 0.2 mV, 0.5 mV, 1.0 mV, and 1.5 mV.ResultsWe analyzed 25 patients (72% men, age 68±15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For a healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 mV and 2.21 mV, respectively.ConclusionsWhen measuring LA BVA in scar and healthy tissue, relevant differences were seen between focal, multielectrode and mini-electrode catheters. Adapted cutoffs for scar and healthy tissue are required.

BACKGROUND: Emerging evidence indicates that a high atrial fibrillation (AF) burden is associated with adverse outcome. However, AF burden is not routinely measured in clinical practice. An artificial intelligence (AI)-based tool could facilitate the assessment of AF burden. OBJECTIVE: We aimed to compare the assessment of AF burden performed manually by physicians with that measured by an AI-based tool. METHODS: We analyzed 7-day Holter electrocardiogram (ECG) recordings of AF patients included in the prospective, multicenter Swiss-AF Burden cohort study. AF burden was defined as percentage of time in AF, and was assessed manually by physicians and by an AI-based tool (Cardiomatics, Cracow, Poland). We evaluated the agreement between both techniques by means of Pearson correlation coefficient, linear regression model, and Bland-Altman plot. RESULTS: We assessed the AF burden in 100 Holter ECG recordings of 82 patients. We identified 53 Holter ECGs with 0% or 100% AF burden, where we found a 100% correlation. For the remaining 47 Holter ECGs with an AF burden between 0.01% and 81.53%, Pearson correlation coefficient was 0.998. The calibration intercept was -0.001 (95% CI -0.008; 0.006), and the calibration slope was 0.975 (95% CI 0.954; 0.995; multiple R(2) 0.995, residual standard error 0.017). Bland-Altman analysis resulted in a bias of -0.006 (95% limits of agreement -0.042 to 0.030). CONCLUSION: The assessment of AF burden with an AI-based tool provided very similar results compared to manual assessment. An AI-based tool may therefore be an accurate and efficient option for the assessment of AF burden.

Background/Aims: Patients with diabetes mellitus (DM) often suffer from gastrointestinal (GI) symptoms, but these correlate poorly to established objective GI motility measures. Our aim is to perform a detailed evaluation of potential measures of gastric and small intestinal motility in patients with DM type 1 and severe GI symptoms.Methods: Twenty patients with DM and 20 healthy controls (HCs) were included. GI motility was examined with a 3-dimensional-Transit capsule, while organ volumes were determined by CT scans.Results: Patients with DM and HCs did not differ with regard to median gastric contraction frequency (DM: 3.0 contractions/minute [interquartile range {IQR}, 2.9-3.0]; HCs: 2.9 [IQR, 2.8-3.1]; P = 0.725), amplitude of gastric contractions (DM: 9 mm [IQR, 8-11]; HCs: 11 mm (IQR, 9-12); P = 0.151) or fasting volume of the stomach wall (DM: 149 cm3 [IQR, 112-187]; HCs: 132 cm3 [IQR, 107-154]; P = 0.121). Median gastric emptying time was prolonged in patients (DM: 3.3 hours [IQR, 2.6-4.6]; HCs: 2.4 hours [IQR, 1.8-2.7]; P = 0.002). No difference was found in small intestinal transit time (DM: 5 hours [IQR, 3.7-5.6]; HCs: 4.8 hours [IQR, 3.9-6.0]; P = 0.883). However, patients with DM had significantly larger volume of the small intestinal wall (DM: 623 cm3 [IQR, 487-766]; HCs: 478 cm3 [IQR, 393-589]; P = 0.003). Among patients, 13 (68%) had small intestinal wall volume and 9 (50%) had gastric emptying time above the upper 95% percentile of HCs.Conclusion: In our study, gastric emptying time and volume of the small intestinal wall appeared to be the best objective measures in patients with DM type 1 and symptoms and gastroenteropathy.

OBJECTIVE: The aim of the study was to evaluate the safety and use of the 3D-Transit system (Motilis SA, Lausanne, Switzerland) and to describe regional gastrointestinal transit times, segmental colonic transit times, and colonic movement patterns in healthy children.METHODS: Twenty-one healthy children (11 girls, median age 10.5 years, range 7-15 years) were included. For evaluation of gastrointestinal transit times and colonic movement patterns, we used the minimally invasive electromagnetic 3D-Transit system. A small electromagnetic capsule (21.5 mm × 8.3 mm) was ingested and tracked through the gastrointestinal tract by a body-worn detector. Regional gastrointestinal transit times were assessed as time between capsule passage of anatomical landmarks. Colonic movement patterns were described and classified based on capsule movement velocity, direction, and distance.RESULTS: One child could not swallow the capsule and 20 children completed the study without any discomfort or side-effects. Median whole gut transit time was 33.6 (range 10.7-80.5) hours, median gastric emptying time was 1.9 (range 0.1-22.1) hours, median small intestinal transit time was 4.9 (range 1.1-15.1) hours, and median colonic transit time was 26.4 (range 6.8-74.5) hours. Median ascending colon/cecum transit time was 9.7 (range 0.3-48.1) hours, median transverse colon transit time was 5.6 (range 0.0-11.6) hours, median descending colon transit time was 2.6 (range 0.01-22.3) hours, and median sigmoid colon/rectum transit time was 7.5 (range 0.1-31.6) hours. Colonic movement patterns among children corresponded to those previously described in healthy adults.CONCLUSIONS: The 3D-Transit system is a well-tolerated and minimally invasive method for assessment of gastrointestinal motility in children.

BACKGROUND: Gastrointestinal (GI) symptoms are common in patients with diabetes mellitus (DM). The electromagnetic 3D-Transit system allows assessment of regional transit times and motility patterns throughout the GI tract. We aimed to compare GI transit times and detailed motility patterns of the colon in patients with DM and GI symptoms to those of healthy controls (HC). We further aimed to determine whether any abnormalities in motility were reversible by cholinergic stimulation.METHODS: We compared 18 patients with DM with 20 HC by means of the 3D-Transit system. Patients were studied before and during oral administration of 60 mg pyridostigmine.KEY RESULTS: Compared to HC, patients had prolonged gastric emptying (DM: 3.3 hours (interquartile range (IQR) 2.6-4.6); HC: 2.3 hours (IQR 1.7-2.7) (P < .01)), colonic transit time (DM: 52.6 hours (IQR 23.3-83.0); HC: 22.4 hours (IQR 18.9-43.6) (P = .02)), and whole gut transit time (DM: 69.4 hours (IQR 32.9-103.6); HC: 30.3 hours (IQR 25.2-49.9) (P < .01)). In addition, compared to HC, patients had prolonged transit time in the ascending colon (DM: 20.5 hours (IQR 11.0-44.0); HC: 8.0 hours (IQR 3.8-21.0) (P < .05)) and more slow retrograde movements in the colon (DM: 2 movements (IQR 1-4); HC: 1 movement (IQR 0-1) (P = .01)). In patients, pyridostigmine increased the number of bowel movements (P < .01) and reduced small intestine transit times (P < .05).CONCLUSIONS: Patients with DM and GI symptoms have longer than normal GI transit times. This is only partly reversible by pyridostigmine. The increased number of retrograde colonic movements in patients could potentially explain the abnormally long transit time in proximal colon.

BACKGROUND: Opioid treatment often causes debilitating constipation. However, it is not well described how opioids affect colonic motility and whether opioid-induced constipation is due to either a decrease of powerful peristaltic contractions or "uncoordinated" peristalsis. The present study aims to investigate the effect of oxycodone on parameters of colonic motility and to determine whether motility is normalized by the opioid antagonist naloxegol.METHODS: In two randomized, double-blind crossover trials, oxycodone or placebo was administered to 25 healthy males (Trial A), while another 24 healthy males were administered oxycodone with naloxegol or placebo (Trial B). Colonic motility was assessed by tracking the progression of an electromagnetic capsule throughout the large intestine. Segmental colonic transit times and capsule movements were calculated using displacement distance and velocity.KEY RESULTS: In Trial A, colonic transit time increased during oxycodone treatment compared with placebo (39 vs 18 hours, P < .01). Displacement during long fast antegrade movements was shorter during oxycodone treatment than with placebo (10 vs 20 cm, P = .03). In Trial B, colonic transit time was faster during oxycodone + naloxegol than during oxycodone + placebo (40 vs 55 hours, P = .049), mainly caused by an increase of the percentwise fraction of distance covered by fast movements in the left colon (P = .001).CONCLUSION & INFERENCES: Oxycodone treatment impaired colonic motility, manifested as increased transit time, specifically decreased long fast antegrade movements, and addition of naloxegol improved motility dynamics. In humans, the increased transit time during opioid treatment is caused by a decrease in long fast movements rather than uncoordinated peristalsis.

BACKGROUND: The Motilis 3D-Transit system allows ambulatory description of transit patterns throughout the gastrointestinal tract and offers an alternative method for studying gastric motility. We aimed to establish normative values for gastric motility assessed with the method.METHOD: A total of 132 healthy volunteers ingested the 3D-Transit capsule for assessment of gastrointestinal transit times. Recordings from 125 subjects were used for definition of normative values. Forty-six subjects were studied on two consecutive days. Recordings were reanalyzed using newly developed software providing information on gastric emptying (GE) as well as contraction frequency and movement during gastric contractions.RESULTS: The median GE time was 2.7 hours (range 0.1-21.2). In 89% of subjects, the capsule passed the pylorus within a postingestion period of 6 hours. The median frequency of gastric contractions was 3.1 per minute (range 2.6-3.8). The frequency was higher in women (3.2, range 2.7-3.8) than in men (3.0, range 2.6-3.5) and increased with age (0.004 per year) (P < .05). The median amplitudes were 35° (range 4-85) when based on rotation of the capsule and 11 mm (range 6-31) when based on capsule change in position. The rotation amplitude was higher in women and decreased with increasing BMI (P < .05). The position amplitude was also higher in women and increased with the amount of calories in the test meal, but decreased with increasing BMI and age (P < .05). Day-to-day variation (P > .05) was considerable while inter-rater variability was small.CONCLUSION AND INFERENCES: We have established normative values for gastric motility assessed with the 3D-Transit system.

Background: The 3D-Transit electromagnet tracking system (Motilis Medica, SA, Lausanne, Switzerland) is an emerging tool for the ambulatory assessment of gastrointestinal (GI) transit and motility. Using this tool, we aimed to derive normative values for region-specific colonic and GI transit times and to assess the influence of age, gender, and body mass index (BMI). Methods: Regional and total colonic transit times (CTT), gastric emptying (GET), small intestinal (SITT), and whole gut (WGTT) transit times were extracted from 111 healthy volunteers from the United Kingdom and Denmark (58 female; median age: 40 years [range: 21-88]). The effects of age, gender, and BMI were assessed using standard statistical methods. Key Results: The ascending, transverse, descending, and rectosigmoid colon transit times accounted for 32%, 34%, 17%, and 17% of total CTT in females, and 33%, 25%, 14%, and 28% of total CTT in males. CTT and WGTT were seen to cluster at intervals separated by approximately 24 hours, providing further evidence of the non-continuous nature of these measurements. Increasing age was associated with longer CTT (P =.021), WGTT (P

Objective: Capsule-based methods for assessment of gastrointestinal (GI) motility have seen great improvements in recent decades. The most recent development is the electromagnetic Motilis 3D-Transit system (3D-Transit). The aim of this paper is to review and discuss the development and technical properties of magnetic tracking of GI motility.Approach: We performed a comprehensive literature review on magnetic tracking in GI research.Main results: The Motility Tracking System was the first capsule based magnetic system to be used in GI motility research. However, the potential of the system was hampered by its stationary and hospitalizing nature. This led to the development of the electromagnetic Motilis 3D-Transit system. The 3D-Transit system is a portable system that allows for assessment of both whole gut and regional transit times and contraction patterns in a fully ambulatory setting in the patients' home environment with only minor restrictions on movements. The spatiotemporal resolution of 3D-Transit allows assessment of segmental colonic transit times and permits an analysis of gastric and colonic movements with a degree of detail unrivalled by other ambulatory methods, such as the Wireless Motility Capsule. Recently, robust normative data on 3D-Transit have been published.Significance: This review provides a current perspective on the use of capsule-based magnetic tracking systems in GI research and how they represent a potentially valuable clinical resource for GI physicians and in GI research.Keywords: colonic contraction patterns; colonic transit time; gastrointestinal motility; gastrointestinal transit time; ingestible capsule; magnetic tracking.

A glass pill for digestive motility tracking with wireless communication is presented. The pill encapsulates three magnetic transmitter coils with a 125 kHz signal, the circuitry required to control the magnetic coil output and the battery. The system provides real time location of the pill inside the digestive tract of the patient using an external detector housed in a wearable jacket. The custom integrated circuit for this application reduces bill-of-materials (BOM) count and significant reduction in power consumption therefore resulting in further size reduction by adapting a smaller battery package. The outcome of the circuit integration enables the glass pill for pediatric use while providing a total pill diameter of 6 mm. The glass pill system operates continuously for 48 hours with a 1.55 V 8 mAh coin cell battery with an average power consumption of 250 microwatts.

BACKGROUND: Gastrointestinal (GI) dysmotility may present secondary to inflammatory bowel disease. The main aim of this study was to investigate GI motility in ulcerative colitis (UC) patients during severe disease activity.METHODS: Twenty patients with severe UC were studied with a novel telemetric capsule system (3D-Transit) designed for minimally invasive, ambulatory assessment of total and regional GI transit times. Ten patients were available for follow-up during remission. Data were compared to those of 20 healthy subjects (HS).KEY RESULTS: Total GI transit time was significantly longer in patients with severe UC (median 44.5 h [range 9.9-102.7 h]) than in HS (median 27.6 h [range 9.6-56.4 h]) (p = 0.032). Additionally, during severe UC, transit time was prolonged through the proximal colon (p = 0.003) and there were strong trends toward longer than normal small intestinal transit time (HS: median 4.9 h [range 3.4-8.3 h] vs severe UC patients: median 5.9 h [range 3.9-11.9 h]; p = 0.053) and colorectal transit times (HS: median 18.2 h [range 1.5-43.7] vs severe UC patients: median 34.9 h [range 0.4-90.9 h]; p = 0.056). Our data further indicate that total GI and colorectal transit times may be prolonged in UC during early remission.CONCLUSIONS & INFERENCES: Total GI transit times are significantly prolonged during severe UC.

Background/aims The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea re-stricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients' regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. Methods Fifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were inves-tigated with 3D-Transit and standard radiopaque markers. Results Total GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman's rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5-47.2) hours in patients versus 25.1 (range: 13.1-142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4-5.5) hours in patients versus 4.4 (range: 1.8-7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9-40.1) hours in patients versus 18.1 (range: 5.0-134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental co-lonic movements was 0.45 (range: 0.03-1.02) per hour in patients and 0.07 (range: 0-0.61) per hour in healthy subjects (P = 0.045). Conclusions Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency of pansegmental colonic movements.

AIM: We aimed to determine colorectal length with the 3D-Transit system by describing a 'centerline' of capsule movement and compare it to known anatomy, as determined by magnetic resonance imaging (MRI). Further, we aimed to test the day-to-day variation of colorectal length assessed with the system.METHOD: The 3D-Transit system consists of electromagnetic capsules that can be tracked as they traverse the gastrointestinal tract. 25 healthy subjects were examined with both 3D-Transit and MRI. Another 21 healthy subjects were examined with 3D-Transit on two consecutive days.RESULTS: Computation of colorectal length from capsule passage was possible in 60 of the 67 3D-Transit recordings. Length of the colorectum measured with MRI and 3D-Transit was respectively 95 cm (75-153 cm) and 99 cm (77-147 cm), P = 0.15. Coefficient of variation (CV) between MRI and 3D-Transit was 7.8%. Apart from the cecum / ascending colon being 26% (P = 0.002) shorter on MRI, there were no other differences in total or segmental colorectal lengths between methods (all P > 0.05). Length of the colorectum measured with 3D-Transit on two consecutive days was 102 cm (73-119 cm) and 103 cm (75-123 cm), P = 0.67. CV between days was 7.3%.CONCLUSIONS: The 3D-Transit system allows accurate and reliable determination of colorectal length compared to MRI derived colorectal length and between days. Antegrade or retrograde capsule movement relative to this centerline, as well as the length and speed of movements may be determined by future studies to allow better classification and treatment in patients with dysmotility. This article is protected by copyright. All rights reserved.

BACKGROUND: Gastrointestinal (GI) motor disorders often involve several regions of the GI tract. Therefore, easy and safe assessment of whole gut and regional motility is valuable for more precise diagnosis. 3D-Transit is a novel method for ambulatory evaluation of total and regional gastrointestinal transit times (GITT) based on the anatomical localization of ingestible electromagnetic capsules. The main purpose of this study was to test the performance of the 3D-Transit system.METHODS: Twenty healthy volunteers each ingested three electromagnetic capsules over a period of two consecutive days. Standard radio-opaque markers (ROM) were also ingested to assess the agreement between total GITT obtained with both methods.KEY RESULTS: Investigations were well-tolerated and three capsules could be tracked simultaneously with minimal data loss (Capsule 1: median: 0.2% of time (range 0-25.3%). Region specific contraction patterns were identified and used for computation of total and regional GITT in all subjects. Inter-observer agreement was 100% for total GITT (median variation 0%) but less for regional GITT. Day-to-day and diurnal variations were significant for total and regional GITT. Total GITT assessed by 3D-Transit capsules were moderately well-correlated to those assessed with standard ROM (Spearman's rho = 0.7).CONCLUSIONS & INFERENCES: 3D-transit is a well-tolerated and minimal invasive ambulatory method for assessment of GI motility. By providing both total and regional transit times, the 3D-Transit system holds great promise for future clinical studies of GI function in health and disease.

Aim Sacral nerve stimulation (SNS) reduces symptoms in up to 80% of patients with faecal incontinence (FI). Its effects are not limited to the distal colon and the pelvic floor. Accordingly, spinal or supraspinal neuromodulation have been suggested as part of the mode of action. The effect of SNS on gastric and small-intestinal motility was studied. Method Using the magnet tracking system, MTS-1, a small magnetic pill was tracked twice through the upper gastrointestinal tract of eight patients with FI successfully treated with SNS. Following a randomized double-blind crossover design, the stimulator was either left active or was turned off for 1 week before investigations with MTS-1. Results The median (range) frequency of gastric con-tractions was 3.05 (2.83–3.40) per min during SNS and 3.04 (2.79?–3.76) per min without (P = NS). The median (range) frequency of contractions in the small intestine during the first 2 h after pyloric passage was 10.005 (9.68–10.70) per min during SNS and 10.09 (9.79–10.29) per min without SNS (P = NS). The median (range) velocity of the magnetic pill during the first 2 h in the small intestine was 1.6 (1.2–2.8) cm/min during SNS and 1.7 (0.8–3.7) cm/min without SNS (P = NS). Small-intestinal propagation mainly occurred during very fast movements (> 15 cm/min), accounting for 51% (42–60%) of the distance 3% (2–4%) of the time during SNS and for 53% (18–73%) of the distance 3% (1–8%) of the time without SNS (P = NS). Conclusion Turning off SNS for 1 week did not affect gastric or small-intestinal motility patterns.

Background. Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis and collagen deposits. Gastrointestinal symptoms of SSc, including abdominal pain, bloating and discomfort, are common but diffuse and their pathophysiology remains obscure. Aim. To investigate the pathophysiology of abdominal pain and discomfort in individuals with SSc. Methods. A total of 15 individuals with SSc (13 women, median age 58 years), all suffering from diffuse abdominal symptoms, and 17 healthy volunteers (12 women, median age 52 years) were evaluated with the Motility Tracking System, MTS-1, measuring gastric emptying (GE) and velocity through the small intestine. SSc patients were also examined for bacterial overgrowth using the hydrogen breath test and with radiopaque markers to determine the total gastrointestinal transit time (GITT). Results. Assessed with the MTS-1, the velocity through the proximal small intestine was significantly reduced in SSc patients (median 0.525 m/h, range 0.11–1.15) when compared to healthy subjects (median 0.91 m/h, range 0.51–1.74) (p = 0.02). Prolonged GE was found in 4 SSc patients (27%) but in none of the healthy volunteers (p = 0.04). Only 3 SSc patients (21%) had positive breath tests for small intestinal bacterial overgrowth. GITT was >3 days in 8 patients (53%). Slow small intestinal transit was associated with a prolonged GITT (p < 0.05). Conclusion. Velocity through the small intestine is significantly reduced in SSc patients with diffuse abdominal symptoms.

Diarrhea is part of the carcinoid syndrome and a significant clinical problem in neuroendocrine tumor (NET) patients. Somatostatin analog (SA) treatment usually alleviates carcinoid diarrhea, but little is known about the objective effects of SA on gastrointestinal transport.To compare gastrointestinal motility in healthy subjects and NET patients before and during SA treatment.Twelve NET patients were studied before and during 4 weeks of SA treatment and were compared with 12 healthy controls. Radio-opaque markers were used for the assessment of total gastrointestinal transit time (GITT). Gastric and small intestinal (SI) transit patterns were described via the external tracking of a small magnetic pill ingested by the subjects.Compared with controls, NET patients had a significantly shorter GITT (0.7 days (0.5-1.5) vs. 1.9 days (1.0-2.3)), a shorter SI transit time (184 min (74-307) vs. 322 min (131-376)), and a faster SI velocity (2.16 cm/min (0.91-3.66) vs. 1.29 cm/min (0.76-2.60)) (all p0.05) but a similar gastric emptying time. SA treatment was followed by a reduction in bowel movements (five per day (3-12) vs. four per day (1-7; p0.02)) as well as an increase in GITT (1.4 days (0.5-2.2; p0.05)). Further, a trend was observed toward increased SI transit time (253 min (145-344; p = 0.08)). Gastric emptying time increased during SA treatment (19 min (4-200) vs. 179 min (5-389; p0.02)). Elevated chromogranin A (CgA), serotonin, and urinary 5-hydroxyindoleacetic acid (U-5HIAA) levels decreased during SA treatment.NET patients have faster than normal total GITT and SI transit times. SA treatment prolongs gastric emptying and GITT, thereby reducing the number of bowel movements.

Fynne L, Worsoe J, Gregersen T, Schlageter V, Laurberg S, Krogh K. Gastric and small intestinal dysfunction in spinal cord injury patients. Acta Neurol Scand: 2012: 125: 123–128. © 2011 John Wiley & Sons A/S. Background – Many patients with spinal cord injury (SCI) suffer from constipation, abdominal pain, nausea, or bloating, and colonic transit times are prolonged in most. Gastric and small intestinal dysfunction could contribute to symptoms but remain to be described in detail. Also, it is obscure whether the level of SCI affects gastric and small intestinal function. Aim – To study orocecal transit time and gastric emptying (GE) in patients with SCI. Methods – Nineteen patients with SCI (7 ♀, median age 54 years) and 15 healthy volunteers (9 ♀, median age 32 years) were included. All were referred because of neurogenic bowel problems. Eleven patients had low SCI (located at conus medullaris or cauda equina) affecting only the parasympathetic nerves to the left colon and eight had high SCI (above Th6) affecting parasympathetic and sympathetic innervation. Subjects ingested a small magnetic pill that subsequently was tracked by the Motility Tracking System – MTS-1 (Motilis, Lausanne, Switzerland). Results – Orocecal transit time was longer than normal both in individuals with high lesions (P

A CMOS integrated RF receiver of a glass pill for tracking motility in the gastrointestinal (GI) tract is presented. The receiver detects a 125 kHz downlink synchronization signal that is sent from an external base station, which is used to trigger the transmission of the 3-axis pill position and also to change the tuning parameters of the receiver system. The incoming downlink RF signal also includes the tuning parameters for the 10-bit resolution adjustable internal ring-oscillator, which generates a 4 MHz clock for providing the 3-axis pill position through the 125 kHz transmitter. The receiver, which is fabricated in UMC 0.18 μm CMOS process is measured using the housing of the glass pill. Experiments show that a maximum operation distance of 80 cm between the base station and the glass pill is achieved. The total power consumption of the integrated solution provides 4.6 times reduction compared to the previous generation tracking pill.

A tracking system with five degrees of freedom based on a 2D-array of 16 Hall sensors and a permanent magnet is presented in this paper. The sensitivity of the Hall sensors is increased by integrated micro- and external macro-flux-concentrators. Detection distance larger than 20cm (during one hour without calibration) is achieved using a magnet of 0.2cm3. This corresponds to a resolution of the sensors of 0.05µTrms. The position and orientation of the marker is displayed in real time at least 20 times per second. The sensing system is small enough to be hand-held and can be used in a normal environment. This presented tracking system has been successfully applied to follow a small swallowed magnet through the entire human digestive tube. This approach is extremely promising as a new non-invasive diagnostic technique in gastro-enterology.

Based on a 2D-array of 16 cylindrical Hall sensors and a permanent magnet, a tracking system with five degrees of freedom is analysed in this paper. The system accuracy is studied, including offset drifts, sensitivity mismatches and the number of sensors. A detection distance as large as 14 cm (during 1 h without calibration) is achieved using a magnet of 0.2 cm3. The position and orientation of the marker is displayed in real time with a sampling frequency up to 50 Hz. The sensing system is small enough to be hand-held and can be used in a normal environment.

Caroline Hedsund,1,2 Iben Moeller Joensson,2 Tine Gregersen,1 Lotte Fynne,1 Vincent Schlageter,3 Klaus Krogh1 1Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, 2Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark; 3Motilis Medica SA, Lausanne, Switzerland Background: Data on small intestinal transit time in healthy children are lacking, and normal values for gastric emptying and colonic transit time are sparse. Conventional methods, including radiopaque markers, scintigraphy, and PillCam™ involve radiation or require the child to swallow a large pill. The minimally invasive, radiation-free Motility Tracking System-1 (MTS-1) has been introduced for description of gastrointestinal motility in adults. The aim of the study was to evaluate the MTS-1 for assessment of gastrointestinal transit times and motility patterns in healthy children. Methods: Twenty-one healthy children (nine girls), median age 10 (range 7–12) years were included. For evaluation with MTS-1, a small magnetic pill was ingested and tracked through the gastrointestinal tract by a matrix of 16 magnetic sensors placed behind a nonmagnetic bed. The children were investigated for 8 hours after swallowing the magnetic pill and again for 4 hours the following morning. After leaving the unit, each child came back after every bowel movement to determine if the pill had been expelled. Results: Nineteen children could swallow the pill. Characteristic contraction patterns were identified for the stomach (three per minute), small intestine (9–11 per minute), and colon (4–5 per minute). Median total gastrointestinal transit time was 37.7 (range 9.5–95.8) hours, median gastric emptying time was 37 (range 2–142) minutes, median small intestinal transit time was 302 (range 164 to >454) minutes, and median colorectal transit time was 38.1 (range 5.6–90.0) hours. Conclusion: MTS-1 allows minimally invasive evaluation of gastrointestinal motility in children. Use of the method is, however, restricted by the nonambulatory setup. Keywords: gastrointestinal motility, gastrointestinal transit time, healthy children, motility tracking system

Background Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. Methods A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4) giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, ϕ). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state. Results Experiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1) (p = 0.03). Conclusion MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

Direct electrical stimulation of the colon offers a promising approach for the induction of propulsive colonic contractions by using an implantable device. The objective of this study was to assess the feasibility to induce colonic contractions using a commercially available battery-operated stimulator (maximum pulse width of 1 ms and maximum amplitude of 10 V). Three pairs of pacing electrodes were inserted into the cecal seromuscular layer of anesthetized pigs. During a first set of in vivo experiments conducted on six animals, a pacing protocol leading to cecum contractions was determined: stimulation bursts with 1 ms pulse width, 10 V amplitude (7-15 mA), 120 Hz frequency, and 30-s burst duration, repeated every 2-5 min. In a second testing phase, an evaluation of the pacing protocol was performed in four animals (120 stimulation bursts in total). By using the battery-operated stimulator, contractions of the cecum and movement of contents could be induced in 92% of all stimulations. A cecal shortening of about 30% and an average intraluminal pressure increase of 10.0 +/- 6.0 mmHg were observed.

The Magnet Tracking System (MTS) is a minimally-invasive technique of continuous evaluation of gastrointestinal motility. In this study, MTS was used to analyse colonic propulsive dynamics and compare the transit of a magnetic pill with that of standard radio-opaque markers. MTS monitors the progress in real time of a magnetic pill through the gut. Ten men and 10 women with regular daily bowel movements swallowed this pill and 10 radio-opaque markers at 8 pm. Five hours of recordings were conducted during 2 following mornings. Origin, direction, amplitude and velocity of movements were analysed relative to space–time plots of the pill trajectory. Abdominal radiographs were taken to compare the progress of both pill and markers. The magnetic pill lay idle for 90% of its sojourn in the colon; its total retrograde displacement accounted for only 20% of its overall movement. Analysis of these movements showed a bimodal distribution of velocities: around 1.5 and 50 cm min–1, the latter being responsible for 2/3 of distance traversed. There were more movements overall and more mass movements in males. Net hourly forward progress was greater in the left than right colon, and greater in males. The position of the magnetic pill correlated well with the advancement of markers. MTS showed patterns and propulsion dynamics of colonic segments with as yet unmet precision. Detailed analysis of slow and fast patterns of colonic progress makes it possible to specify the motility of colonic segments, and any variability in gender. Such analysis opens up promising avenues in studies of motility disorders.

Background Direct colonic electrical stimulation may prove to be a treatment option for specific motility disorders such as chronic constipation. The aim of this study was to provoke colonic contractions using electrical stimulation delivered from a battery-operated device. Methods Electrodes were inserted into the caecal seromuscular layer of eight anaesthetized pigs. Contractions were induced by a neurostimulator (Medtronic 3625). Caecal motility was measured simultaneously by video image analysis, manometry and a technique assessing colonic transit. Results Caecal contractions were generated using 8–10 V amplitude, 1000 µs pulse width, 120 Hz frequency for 10–30 s, with an intensity of 7–15 mA. The maximal contraction strength was observed after 20–25 s. Electrical stimulation was followed by a relaxation phase of 1·5–2 min during which contractions propagated orally and aborally over at least 10 cm. Spontaneous and stimulated caecal motility values were significantly different for both intraluminal pressure (mean(s.d.) 332(124) and 463(187) mmHg respectively; P < 0·001, 42 experiments) and movement of contents (1·6(0·9) and 3·9(2·8) mm; P < 0·001, 40 experiments). Conclusion Electrical stimulation modulated caecal motility, and provoked localized and propagated colonic contractions.

Fluoroscopic verification of nasogastric (NG) feeding tube placement is inconvenient and involves radiation exposure. We tested whether the position of an NG tube can be assessed reliably by a recently introduced magnet-tracking system.A small permanent magnet was attached at the end of an NG tube and its position was monitored using an external sensor array connected to a computer. NG tube trajectory, spontaneous movements of the magnet, and its position relative to the lower esophageal sphincter (LES) and xiphisternum were assessed in 22 healthy subjects and compared with esophageal manometry. In 12 subjects, localization of the magnet was also compared with fluoroscopy.Magnet-tracking displayed NG tube tip movement reproducibly as it moved vertically in the esophagus and then laterally into the stomach. Compared with manometry, the accuracy and sensitivity of magnet tracking for localization of the NG tube tip, above or below the diaphragm, were 100%. Compared with fluoroscopy, the accuracy of NG tube localization by magnet tracking was 100%. With the magnet in the stomach, but not in the esophagus or LES, low amplitude displacements at a frequency of 3 per minute, consistent with gastric slow wave activity, were observed.Magnet tracking allows accurate, real-time, 3-dimensional localization of an NG tube with respect to anatomic landmarks. Recorded motor patterns are indicative of the position of the NG tube. Magnet tracking may be a useful tool for bedside placement of nasogastric and enteral feeding tubes.

We present a new graphical tool to investigate the time evolution of phase-synchronization clusters and apply it to a computer model of the intestine consisting of coupled oscillators. The method estimates the synchronized zones using a covariance analysis of the electrical activity to detect any linear relationship between segments of the intestine. Synchronization expresses itself by the formation, merging and destruction of clusters, which are groups of oscillators with a related dynamics. Specific patterns of cluster evolution were generated with different frequency gradients, reflecting the different properties of segments of the intestine. This tool allowed us to identify characteristic patterns for the small and the large intestine.

We have studied the sensitivity of Hall devices using planar magnetic flux concentrators of various lengths. By placing magneto-concentrators (MCs) on Hall device, we obtained sensitivity up to 100 V/T for a bias current of 1 mA and for a length of the MCs of 50 mm. This value is about 1000 times better then that of a conventional silicon Hall devices, without adding significant amount of noise. The magnetic gain is achieved using a combination of micro-integrated and macroscopic magnetic flux concentrators.

Background: The Motilis 3D-Transit system tracks electromagnetic capsules as they traverse the gastrointestinal tract. The method is minimally invasive and ambulatory. Analysis has previously been limited to regional gut transit times, but new methods may allow detailed analysis of colonic motility. Methods: Parameters of colonic motility were analyzed from 34 3D-Transit recordings performed in healthy volunteers (median age 28 years; 8 F). Characteristic propulsive velocities and lengths of movement were determined to quantify common movement patterns. Data from seven patients with severe chronic diarrhea were included for comparison. Key Results: Lack of capsule motion accounted for 82% (75%-87%) of total colonic transit time. Propulsive velocities were distributed with peaks at 0.5 cm/min (antegrade or retrograde) and 50 cm/min (antegrade). Based on velocity and length of propagation, five motor patterns were identified; (a) long fast antegrade, (b) fast antegrade, (c) slow antegrade, (d) slow retrograde, and (e) fast retrograde movements. Long fast antegrade movements were median 21 cm (10-96 cm). Capsule progression was faster during daytime than at night (5.9 cm/h vs 0.8 cm/h; P

Purpose: Silent brain infarcts (SBI) are frequently detected in patients with atrial fibrillation (AF), but it is unknown whether SBI are linked to autonomic dysfunction. We aimed to explore the association of autonomic dysfunction with SBI in AF patients., Methods: 1,358 AF patients without prior stroke or TIA underwent brain MRI and 5-min resting ECG. We divided our cohort into AF patients who presented in sinus rhythm (SR-group, n = 816) or AF (AF-group, n = 542). HRV triangular index (HRVI), standard deviation of normal-to-normal intervals, mean heart rate, root mean square root of successive differences of normal-to-normal intervals, 5-min total power and power in the low frequency, high frequency and very low frequency range were calculated. Primary outcome was presence of SBI in the SR group, defined as large non-cortical or cortical infarcts. Secondary outcomes were SBI volumes and topography., Results: Mean age was 72 +/- 9 years, 27% were female. SBI were detected in 10.5% of the SR group and in 19.9% of the AF group (p < 0.001). HRVI, Conclusion: Impaired HRVI is associated with SBI in AF patients. AF patients with autonomic dysfunction might undergo systematic brain MRI screening to initiate intensified medical treatment.