Primary Esophageal Peristalsis Research Articles

Effects of Codeine on Esophageal Peristalsis in Patients With Ineffective Esophageal Motility: Studies Using High-resolution Manometry.

This study aims to evaluate the effects of acute codeine administration on primary and secondary esophageal peristalsis in patients with ineffective esophageal motility (IEM). Eighteen IEM patients (8 women; mean age 37.8 years, range 23-64 years) were enrolled in the study. The patients underwent high-resolution manometry exams, consisting of 10 single wet swallows, multiple rapid swallows, and ten 20 mL rapid air injections to trigger secondary peristalsis. All participants completed 2 separate sessions, including acute administration of codeine (60 mg) and placebo, in a randomized order. Codeine significantly increased the distal contractile integral (566 ± 81 mmHg∙s∙cm vs 247 ± 36 mmHg∙s∙cm, P = 0.001) and shortened distal latency (5.7 ± 0.2 seconds vs 6.5 ± 0.1 seconds, P < 0.001) for primary peristalsis compared with these parameters after placebo treatment. The mean total break length decreased significantly after codeine treatment compared with the length after placebo (P = 0.003). Codeine significantly increased esophagogastric junction-contractile integral (P = 0.028) but did not change the 4-second integrated relaxation pressure (P = 0.794). Codeine significantly decreased the frequency of weak (P = 0.039) and failed contractions (P = 0.009), resulting in increased frequency of normal primary peristalsis (P < 0.136). No significant differences in the ratio of impaired multiple rapid swallows inhibition and parameters of secondary peristalsis were detected. In IEM patients, acute administration of codeine increases contraction vigor and reduces distal latency of primary esophageal peristalsis, but has no effect on secondary peristalsis. Future studies are required to further elucidate clinical relevance of these findings, especially in the setting of gastroesophageal reflux disease with IEM.

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

EndoFLIP Topography: Motor Patterns in an Obstructed Esophagus

Bolus flow and biomechanical properties of the esophageal wall during primary esophageal peristalsis: Effects of bolus viscosity and posture.

Studies show that intraluminal impedance recordings of the esophagus allow one to measure the luminal distension during peristalsis, an important parameter for calculation of the biomechanical properties of esophageal wall. The goal was to determine the effect of subject posture and bolus viscosity on the biomechanical properties of esophageal wall, and the rate of bolus flow along the length of the esophagus during primary peristalsis. High-resolution manometry impedance recordings were obtained in 14 normal healthy subjects. Swallows of 10ml saline and viscous bolus were recorded in the supine and Trendelenburg positions. User identified the region of interest, and a custom-designed software extracted parameters of interest such as bolus flow rate, esophageal wall tension, and esophageal wall distensibility in four equal segments of the esophagus. Bolus flow rate decreases along the length of the esophagus, being slowest in the distal esophagus. Bolus flow rate is smaller in the Trendelenburg position and with viscous bolus as compared with supine position and saline bolus. Esophageal wall tension is greater in the Trendelenburg position and with viscous bolus as compared with the supine position and saline bolus. The esophageal wall distensibility is larger in the distal as compared with proximal esophagus, which is true for both the saline and viscous bolus. We report, for the first time, bolus flow rate and biomechanical properties of the esophageal wall during swallow-induced primary peristalsis. Future studies may investigate biomechanical basis of esophageal motility disorders using the methodology described.

Effects of phosphodiesterase-5 inhibitor sildenafil on esophageal secondary peristalsis: Studies with high-resolution manometry.

Secondary peristalsis contributes to the clearance of retained refluxate from the esophagus. Sildenafil, a phosphodiesterase-5 inhibitor, inhibits primary esophageal peristalsis, but its effects on secondary peristalsis remain unknown. This study sought to investigate whether sildenafil could influence physiological characteristics of secondary peristalsis by applying high-resolution manometry (HRM). Seventeen healthy volunteers (15 men and 2 women, aged 30.2±6.4years) underwent two HRM studies on separate days following the administration of either a placebo or 50mg of sildenafil in a random order. Both studies were performed using a water-perfused HRM catheter containing one air injection channel positioned in the mid-esophagus. Secondary peristalsis was stimulated by a rapid mid-esophageal injection of 10 or 20mL of air 1h after the administration of either the placebo or sildenafil. The frequency and distal contractile integral of secondary peristalsis were then compared. Complete secondary peristalsis triggered by the 20-mL air injection was more frequent than observed with the 10-mL air injection (P<0.001). The vigor of secondary peristalsis triggered by the injection of either volume of air was lower than that of primary peristalsis (P<0.001). Sildenafil significantly reduced the success rate (P≤0.001) and vigor (P<0.001) of secondary peristalsis relative to the effects of the placebo at both distension volumes. Secondary peristalsis can be successfully triggered by rapid air injection during HRM. Sildenafil reduces both the success rate and the vigor of secondary peristalsis, similar to that seen with primary peristalsis.

EFFECT OF BOLUS SIZE ON DEGLUTITION AND ESOPHAGEAL TRANSIT IN HEALTHY DOGS.

Contrast videofluoroscopy is the gold standard procedure for evaluating dysphagia in humans, but quantitative measures vary depending on bolus size and consistency. We hypothesized that quantitative measures made during videofluoroscopy of swallowing in dogs would differ between bolus sizes and consistencies. Ten healthy adult dogs were enrolled a prospective, crossover experimental study and underwent contrast videofluoroscopy while swallowing liquid (5, 10, and 15 ml) and canned food (3, 8, and 12 g) boluses. Maximum pharyngeal contraction occurred significantly later with medium solid boluses than with medium liquid boluses, with a mean difference of 0.021 s (adjusted P = 0.042). Upper esophageal sphincter opening occurred significantly earlier with large solid boluses than with medium solid boluses, with a mean difference of 0.018 s (adjusted P = 0.025). Thoracic esophageal transit time was significantly longer with small solid boluses than with small liquid boluses, with a mean difference of 0.68 s (adjusted P = 0.004). Odds of primary esophageal peristalsis occurring were significantly (18.5 times) higher with large solid vs. large liquid boluses (adjusted P = 0.031). No other statistical comparisons reached significance. Based on these results, we recommend a standardized approach to videofluoscopy in dogs with determination of quantitative measures using medium liquid and soft food boluses to minimize effects of size. Furthermore, we conclude that measurements made on liquid swallows should not be directly compared to measurements made on soft food boluses.

Quantitative Differences Between Primary and Secondary Peristaltic Contractions of the Esophagus

Differences in contraction characteristics between primary and secondary peristalsis have only been scarcely studied. Recently new measures of contractile activity in the human esophagus were developed. The study aims were to use combined manometry and impedance planimetry [pressure-cross-sectional area (P-CSA)] recordings from healthy volunteers to examine esophageal peristalsis, and, furthermore, to investigate the effect of the motility enhancing drug erythromycin to study differential effects on the two types of contractions. Sixteen healthy volunteers participated in the study [mean age 23 (range, 19-34) years, 6 females]. An esophageal probe with a bag for CSA measurement was positioned 10 cm above the lower esophageal sphincter. Bag volume was increased stepwise from 5 to 25 ml before and after intravenous infusion of 250 mg erythromycin. Swallow-evoked primary and distension-evoked secondary esophageal peristalsis were compared with regard to (1) pressure amplitude, (2) CSA amplitude, (3) preload tension (wall tension before an evoked contraction), (4) contractile tension, and (5) work outputs. Primary peristalsis induced more efficient contractions as the contraction amplitudes, work output and contractile tension were higher compared to secondary peristalsis (P < 0.001). Erythromycin induced change in CSA during distension-evoked secondary peristalsis (CSA before 212.9 ± 26.8 vs. after 180.5 ± 23.3, P < 0.05). The sensitivity to esophageal distension increased with the distending volume both before and during erythromycin. The sensitivity was not changed by erythromycin (P = 0.6). Esophageal primary peristaltic contractions were more forceful with longer duration, and higher work output compared to secondary peristalsis contractions. Erythromycin affected peristalsis only to a minor degree.

Esophagus and Its Function Related to Gastro-esophageal Reflux

ABSTRACT The main function of the esophagus is to transport food from the mouth into stomach. Anatomical structures, innervations and blood supplies are needed in order to transport the food into stomach. Mastication stimulates the parasympathetic nerves that regulate salivary, gastric and pancreatic secretion. Saliva secretion stimulates swallowing and increases primary esophageal peristalsis, helps in clearing the esophagus from refluxed material. Swallowing induces peristaltic of esophagus that propulses a solid bolus down the esophagus into the stomach. Innervations are important for esophagus to do its function. One of the most important is coordination between the various reflexes. Delayed clearance of acid from the esophageal and decreased pressure of the lower sphincter esophagus (LES) are the major mechanisms involved in the development of esophagitis. The resistance of the mucosa to the noxious effect of the refluxed material (acid, pepsin, chymotrypsin and trypsin, bile, etc.) is different from person to person. The LES pressure is a defense mechanisms to prevent gastro-esophageal reflux disease ( xe GERD). The LES pressure decreases postprandially. The frequency of postprandinal GER is related to the meal size. Gastric bolus feeding is related to greater intragastric pressure causes more of transient LES relaxations. Osmolality and volume of the feeding slow gastric emptying and incrase postprandial GER. The occurrence of xe GERD is associated with whether or not the preventive factors are functioning. Other preventive factors for xe GERD are esophageal peristalsis, secretion and mucosal resistance, gravity and position, the LES tone and angle of his. Patient with xe GERD should be searched for any disturbances on those factors. Keywords: gastroesophageal reflux diseases, lower esophageal sphincter, esophagitis, peristaltic

Effects of Body Positioning on Swallowing and Esophageal Transit in Healthy Dogs

Contrast videofluoroscopy is the imaging technique of choice for evaluating dysphagic dogs. In people, body position alters the outcome of videofluoroscopic assessment of swallowing. That esophageal transit in dogs, as measured by a barium esophagram, is not affected by body position. Healthy dogs (n=15). Interventional, experimental study. A restraint device was built to facilitate imaging of dogs in sternal recumbency. Each dog underwent videofluoroscopy during swallowing of liquid barium and barium-soaked kibble in sternal and lateral recumbency. Timing of swallowing, pharyngeal constriction ratio, esophageal transit time, and number of esophageal peristaltic waves were compared among body positions. Transit time in the cervical esophagus (cm/s) was significantly delayed when dogs were in lateral recumbency for both liquid (2.58+/-1.98 versus 7.23+/-3.11; P=.001) and kibble (4.44+/-2.02 versus 8.92+/-4.80; P=.002). In lateral recumbency, 52+/-22% of liquid and 73+/-23% of kibble swallows stimulated primary esophageal peristalsis. In sternal recumbency, 77+/-24% of liquid (P=.01 versus lateral) and 89+/-16% of kibble (P=.01 versus lateral) swallows stimulated primary esophageal peristalsis. Other variables were not significantly different. Lateral body positioning significantly increases cervical esophageal transit time and affects the type of peristaltic wave generated by a swallow.

Esophageal ileus following laparoscopic fundoplication

Early postoperative dysphagia occurs in most patients following laparoscopic fundoplication. Whether dysphagia is associated with a change in esophageal motor function and/or a change in gastroesophageal junction characteristics is unknown. Esophageal motility in the early postoperative period has not been evaluated previously. Esophageal motility was studied on the first postoperative day in 10 patients who underwent laparoscopic Nissen fundoplication and 10 patients who underwent laparoscopic cholecystectomy (control group), using standard perfusion manometry. Primary peristalsis on water swallows following fundoplication elicted a median response of 5% successful peristalsis compared with median response of 100% successful peristalsis following cholecystectomy (P = 0.05). The fundoplication was associated with failure of primary esophageal peristalsis in 7/10 patients, compared to 2/10 patients who underwent cholecystectomy (P = 0.068 Fisher's exact test). Three months after fundoplication, in nine patients studied, primary peristalsis was similar to peristalsis observed preoperatively in seven patients and two patients still had an aperistaltic esophagus. In this study, esophageal manometry 1 day after surgery demonstrated grossly disturbed esophageal motility in most patents following laparoscopic fundoplication, compared to normal motility following laparoscopic cholecystectomy. Peristalsis improved at 3 months or more following surgery. This suggests that an 'esophageal ileus' occurs during the early period after laparoscopic fundoplication.

Primary and secondary esophageal contractions in patients with gastroesophageal reflux disease

We studied the primary and secondary esophageal peristalsis in 36 patients with heartburn and acid regurgitation and in 14 asymptomatic volunteers. Primary peristalsis was elicited by ten swallows of a 5-mL bolus of water and secondary peristalsis was elicited by intra-esophageal infusion of 5, 10, and 15 mL water, 0.1 N hydrochloric acid and air. Esophageal contractions were measured by an 8-lumen manometric catheter assembly incorporating a 6-cm sleeve device. Contractions were registered at 3, 9, and 15 cm from the upper margin of the sleeve and the infusion was done through a side hole located at 12 cm. Twenty patients had normal endoscopic esophageal examination, 10 with normal (group I) and 10 with abnormal pH-metric examination (group II), and 16 had esophagitis (group III). The amplitude of contractions after swallows was lower (97.8 +/- 10.0 mmHg) in the distal esophagus of group III patients than in controls (142.3 +/- 14.0 mmHg). Patients of group III had fewer secondary contractions (water: 25% of infusion) than patients of the other groups and controls (67% of infusion). Patients of group III also had a lower amplitude of secondary peristalsis in the distal esophagus (water: 70.1 +/- 9.6 mmHg) than controls (129.2 +/- 18.2 mmHg). We conclude that patients with esophagitis have an impairment of primary and secondary peristalsis in the distal esophagus.

Illness behavior and laparoscopic antireflux surgery: tailoring the wrap to suit the patient

Psychological factors are believed to play a role in gastroesophageal reflux disease. It has previously been shown that preoperative illness behavior influences the outcome after laparoscopic Nissen fundoplication. Between August 2001 and June 2004 we considered a partly subjective assessment of illness behavior when selecting patients with gastroesophageal reflux disease for laparoscopic anterior partial (n = 77) or total fundoplication (n = 90). A prospective questionnaire study of illness behavior was also undertaken and the results were correlated with clinical follow up after 12 months. There was a statistically significant difference in age (P < 0.001), primary esophageal peristalsis on manometry (P = 0.037) and two illness behavior category scores related to hypochondriasis (P = 0.041 and P = 0.025) between laparoscopic anterior partial fundoplication and Nissen total fundoplication groups. Despite these differences, there was no significant correlation between preoperative illness behavior score and patient satisfaction in either group. There was a statistically significant negative correlation between the ability to express personal feelings and postoperative heartburn score in those who had a laparoscopic anterior partial fundoplication (P = 0.048). The clinical outcome in both groups was good to excellent in terms of postoperative heartburn and satisfaction scores. A tailored approach in the choice of wrap, taking into account psychological factors preoperatively, is an appropriate strategy for laparoscopic fundoplication.

Total fundoplication is superior to partial fundoplication even when esophageal peristalsis is weak.

About a decade ago, partial (240 degrees) fundoplication became popular for treating gastroesophageal reflux disease in cases where the patient's primary esophageal peristalsis was weak. A total (360 degrees) fundoplication was reserved for patients with normal peristalsis (tailored approach). The theory was that partial fundoplication was an adequate antireflux measure, and by posing less resistance for the weak esophageal peristalsis to overcome, it would give rise to less dysphagia. Short-term results seemed to confirm these ideas. This study reports the longterm followup of patients in whom a tailored approach (type of wrap chosen to match esophageal peristalsis) was used, and the results of a nonselective approach, using a total fundoplication regardless of the amplitude of esophageal peristalsis. We analyzed clinical and laboratory findings in 357 patients who had an operation for gastroesophageal reflux disease between October 1992 and November 2002. Group 1 was composed of 235 patients in whom a tailored approach was used between October 1992 and December 1999 (141 patients, partial fundoplication and 94 patients, total fundoplication). Group 2 contained 122 patients in whom a nonselective approach was used (total fundoplication regardless of quality of peristalsis). In group 1, heartburn from reflux (ie, pH monitoring test was abnormal) recurred in 19% of patients after partial fundoplication and in 4% after total fundoplication. In group 2, heartburn recurred in 4% of patients after total fundoplication. The incidence of postoperative dysphagia was similar in the two groups. These data show that laparoscopic partial fundoplication was less effective than total fundoplication in curing gastroesophageal reflux disease, and compared with a partial (240 degrees) fundoplication, a total (360 degrees) fundoplication was not followed by more dysphagia, even when esophageal peristalsis was weak.

Esophageal function and Sjögren's syndrome.

The frequency and characteristics of esophageal dysmotility in Sjögren's syndrome (SS) are as controversial as their related symptoms. We evaluated esophageal function and gastroesophageal reflux (GER) in 21 SS patients using manometry and 24-hr esophageal pH monitoring. All patients complained of xerostomia, 33% of dysphagia, and 62% of heartburn. Compared to controls, the mean percentage abdominal length of their lower esophageal sphincters (LES) and resting LES pressures were significantly lower, with no difference in primary esophageal peristalsis. Tertiary waves without swallowing were detected in 29% of them and pathological GER in 67%. Symptoms, esophageal motor abnormalities, and reflux features were similar in primary and secondary SS. ANOVA indicated that dysphagia was unrelated to the esophageal impairments and GER analysis results, while heartburn was significantly associated with GER severity. Esophageal acid-exposure time was significantly longer in SS patients with distal tertiary waves, while proximal esophagus wave velocity was significantly lower. While SS patients have nonspecific esophageal motility disorders and frequently GER disease, early and accurate diagnosis of GER is essential to identify SS patients at risk for acidic reflux, especially because the acid-clearance capacity of the esophagus is already diminished by the lack of saliva.

Characteristics of primary and secondary esophageal peristalsis during maturation in human neonates

Characteristics of primary and secondary esophageal peristalsis during maturation in human neonates

Loss of secondary esophageal peristalsis is not a contributory pathogenetic factor in posterior laryngitis.

Secondary esophageal peristalsis helps prevent the entry of gastric acid into the pharynx by clearing the refluxed gastric contents back into the stomach. Because the loss of this mechanism may contribute to the pathogenesis of reflux-induced laryngeal disorders, our aim was to study the frequency of stimulation and parameters of secondary esophageal peristalsis in patients with posterior laryngitis (PL). We studied 14 patients (45 +/- 5 years) with PL documented by videolaryngoscopy and 11 healthy controls (46 +/- 6 years). The upper esophageal sphincter (UES) pressure was monitored by a sleeve assembly incorporating an injection port 5 cm distal to the sleeve. The esophageal body and lower esophageal sphincter (LES) pressures were measured by an LES sleeve assembly. Primary esophageal peristalsis was induced by 5-mL water swallows. Secondary esophageal peristalsis was induced by abrupt injection of volumes of air, incrementally increased by 5 mL, into the esophagus. Secondary esophageal peristalsis could not be elicited by injection of any volume (up to 60 mL) in 3 PL patients and 2 controls. These 5 subjects had normal primary peristalsis. The threshold volume of air required to stimulate secondary esophageal peristalsis in PL patients (median, 15 mL) was similar to that of controls (median, 10 mL). The parameters of the secondary esophageal peristaltic pressure wave were similar in both groups, and in both groups, they were similar to those of primary peristalsis. The UES response to the injection of the threshold volume that induced secondary esophageal peristalsis in PL patients was contraction in 58% of the trials, partial relaxation in 3%, and no response in 39%. The findings were similar to those in the controls. The LES response to injection of the threshold volume was complete relaxation in both the PL patients and the controls. We conclude that the integrity of secondary esophageal peristalsis is preserved in PL patients.

Swallowing reflex and brain stem neurons activated by superior laryngeal nerve stimulation in the mouse.

The purpose of the present study was to identify vagal subnuclei that participate in reflex swallowing in response to electrical stimulation of the left superior laryngeal nerve (SLN). SLN stimulation at 10 Hz evoked primary peristalsis, including oropharyngeal and esophageal peristalsis, and LES relaxation. It also induced c-fos expression in interneurons in the interstitial (SolI), intermediate (SolIM), central (SolCe), dorsomedial (SolDM) and commissural (SolC) solitary subnuclei. Neurons in parvicellular reticular nucleus (PCRt) and area postrema (AP) and motoneurons in the semicompact (NAsc), loose (NAl), and compact (NAc) formations of the nucleus ambiguus and both rostral (DMVr) and caudal (DMVc) parts of the dorsal motor nucleus of vagus were also activated. The activated neurons represent all neurons concerned with afferent SLN-mediated reflexes, including the swallowing-related neurons. SLN stimulation at 5 Hz elicited oropharyngeal and LES but not esophageal responses and evoked c-fos expression in neurons in SolI, SolIM, SolDM, PCRt, AP, NAsc, NAl, and DMVc but not in SolCe, NAc, or DMVr. These data are consistent with the role of SolI, SolIM, SolDM, NAsc, NAl, and DMVc circuit in oropharyngeal peristalsis and LES relaxation and SolCe, NAc, DMVc, and DMVr in esophageal peristalsis and LES responses.

Disruption of primary and secondary esophageal peristalsis by afferent stimulation.

Recent studies have shown that afferent signals originating from the pharynx inhibit progression of primary esophageal peristalsis. Our aim was to further elucidate the effect of esophageal and pharyngeal afferent stimulation on primary and secondary esophageal peristalsis. We studied the effect of esophageal air distension and pharyngeal water stimulation on progression of primary and secondary peristalsis in nine healthy volunteers aged 27 +/- 2 yr (4 men, 5 women). At a threshold volume, rapid injection of water into the pharynx, directed posteriorly, resulted in complete halt of the progressing secondary and primary esophageal peristalses in both the proximal and distal esophagus. The threshold volume of injected water for inducing inhibition was similar for secondary (0.6 +/- 0.2 ml) and primary (0.5 +/- 0.1 ml) esophageal peristalsis. Progression of primary peristalsis induced by a dry swallow and secondary peristalsis induced by intraesophageal air distension were completely inhibited by intraesophageal injection of 15 +/- 2 ml of air in 70% and 75% of the trials, respectively. We conclude that afferent signals induced by esophageal air distension and pharyngeal water stimulation inhibit propagation of both primary and secondary esophageal peristalsis, suggesting a shared neural control mechanism for these types of peristalsis.

Involvement of nitric oxide in human primary esophageal peristalsis

European Journal of Gastroenterology & Hepatology: December 1998 - Volume 10 - Issue 12 - p A37

Inhibition of progressing primary esophageal peristalsis by pharyngeal water stimulation in humans

BACKGROUND & AIMS: Sensory impulses initiated from the pharynx exert differing effects on the deglutitive apparatus. They have an inhibitory effect on the lower esophageal sphincter but an excitatory effect on the upper esophageal sphincter. The aim of this study was to systematically investigate the effect of pharyngeal sensory impulses evoked by water stimulation on the progressing esophageal peristalsis. METHODS: Sixteen healthy young volunteers were studied in the supine position. The presence of normal peristalsis was verified. Esophageal peristalsis was recorded 3, 6, 9, 12, 15, and 18 cm above the lower esophageal sphincter. Pharyngeal stimulation was performed by injecting a predetermined threshold volume into the pharynx 2 cm above the upper esophageal sphincter, directed posteriorly. The injections were timed to coincide with the arrival of the peristaltic wave induced by dry swallows at respective recording sites. RESULTS: Injection of the threshold volume (0.5 +/- 0.1 mL) stopped the progression of peristalsis at both the striated and smooth muscle esophagus. Topical pharyngeal anesthesia blocked this inhibitory effect (P < 0.01). CONCLUSIONS: Sensory impulses initiated from the pharynx evoked by water injection inhibit the progression of primary esophageal peristalsis. Although the clinical significance of these findings is not determined, they may explain the mechanism of some of the failed esophageal peristalsis. (Gastroenterology 1996 Feb;110(2):419-23)

Correlation of lower esophageal mucosal ring and lower esophageal sphincter pressure

We assessed the relationship of lower esophageal sphincter pressure (LESP) to presence and absence of lower esophageal mucosal ring (LEMR) in 66 patients to determine if the LEMR was more likely related to prolonged sphincter hypotension. This potential relationship is of interest because LEMR may be due to reflux esophagitis. Each patient had radiographic and manometric studies, and both examinations were done within one week of each other. The mean LESP in patients with LEMR was 23.8 mm Hg (range 4.2-64 mm Hg) compared to 28.7 mm Hg (range 8-59 mm Hg) in patients without LEMR; the difference was not statistically significant. Patients with LEMR were also divided into three subgroups according to the diameter of the rings (< or = 13 mm, 14-19 mm, > or = 20 mm). There was no significant relationship between the caliber of LEMR and LESP (P > 0.05). Presence of LEMR did not affect the amplitude or duration of primary esophageal peristalsis. These results do not support a relationship between LEMR and prolonged LESP hypotension or abnormal esophageal motility. However, other pathogenetic mechanisms involved in producing reflux esophagitis not related to prolonged sphincter hypotension were not studied.