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Capabilities and limitations of electrogastrogram in the detection of normal gastric slow wave and gastric dysrhythmias
April 2000
a bolus of 0.025 Ulkg) in 7 dogs. Visual and computerized analyses were performed. Results: I) Origin of dysrhythmias. A total 577 min of bradygastria and 20I min of tachygastria were observed in the recordings. A majority of bradygastria was originated in the proximal stomach, 80.5::':9.4%, compared with 8.6::':8.6% originated in the distal antrum (p
4458 GASTRIC DYSRHYTHMIA IS INDICATIVE OF GASTRIC ANTRAL HYPOMOTILITY. Liwei Qian, Zhishun Wang, Jiande Chen, Univ of Texas Med Branch, Galveston, TX. Gastric myoelectrical dysrhythmia has been frequently reported in patients with gastric motor disorders, indirectly suggesting an association of gastric dysrhythmia with dis-motility. The aim of this study was to investigate the direct correlation of gastric dysrhythmia with gastric muscle tone in dogs. Methods: Five healthy female hound dogs (15-22 kg) were implanted with 4 pairs of serosal electrodes along the greater curvature of the stomach at an interval of 4 em with the most distal pair 2 cm above the pylorus. A strain gauge (SG) was sutured on the serosal wall parallel to the most distal pair of electrodes. After the dogs were completely recovered, gastric myoelectrical activity (GMA) and (SG) signal were recorded for 80 min in the fasting state in a few sessions. Medical intervention (vasopressin: 0.5 Ulkg infused over 20 min or glucagon O.1Ulkg infused over 40min plus a bolus of 0.025 Ulkg) was performed after 20-min baseline to induce gastric dysrhythmia. Computerized spectral analysis was applied to calculate the percentage of regular slow waves from the distal channel. The energy of the strain gauge signal was derived by calculating the area under the curve. Results: I) The SG energy was significantly decreased during the 20/40min infusion of either vasopressin/glucagon. The Total energy was 48.4 ::': 1.3 dB at baseline. and decreased to 36.6 ::': 4.5 dB, 44.5 ::': 4.3 dB, 45.8 ::': 1.9 dB during the following three 20-min periods with and after the infusion (p<0.05). 2) The regularity of GMA was 90.1::': 5 % at baseline, reduced to 13.9 ::': 3.9%, and 52.2 ::': 6.4 % during the following two 20-min periods with and after infusion (p0.05). Conclusion: Vasopressin and glucagon inhibit gastric tone and impairs gastric slow waves. Gastric dysrhythmias are associated with the reduced antral muscle tone and is indicative of antral hypomotility.
4459
CAPABILITIES AND LIMITATIONS OF ELECTROGASTROGRAM IN THE DETECTION OF NORMAL GASTRIC SLOW WAVE AND GASTRIC DYSRHYTHMIAS. Zhishun Wang, Liwei Qian, Tatsuyuki Ueno, Hui Ouyang, Jiande Chen, Univ of Texas Moo Branch, Galveston, TX. Electrogastrography (EGG) has been widely used in the detection of gastric dysrhythmias in patients with motility disorders. While studies have been
AGAA851
performed to confirm that 3 cycles/min (cpm) waves in the EGG are of gastric origin, little is known on the accuracy of the EGG in the detection of gastric dysrhythmias. The aim of this study was to quantitatively assess the capabilities and limitations of the EGG in the detection of gastric dysrhythmias. Methods: The study was performed in 5 healthy female hound dogs (14-19kg) surgically implanted with four pairs of bipolar electrodes on gastric serosa. After the dogs were completely recovered from surgery. the study was performed in the fasting state using the following protocol: 20 min baseline, 20 min vasopressin infusion (0.5u/kg, in 20ml saline) and 40 min recovery. Four channels of bipolar surface electrodes were placed on abdominal skin over the stomach. Spectral and cross-spectral analysis methods developed in our laboratory were applied to compute the percentage of regular slow waves and slow wave coupling from both the serosal and surface recordings. Results: I) The EGG was capable of detecting the percentage of normal slow waves accurately in the different periods of the experiment (serosal vs. EGG, baseline: 79.8% vs. 70.4%, r=0.95, p<0.02; infusion: 32.9% vs. 35.6%, r=0.95, p<0.02; recovery: 61.0% vs. 52.9%, r=0.91, p<0.04). It was also able to detect the slow wave coupling. 2) Similarly, the EGG was able to accurately detect bradygastria. The percentages of bradygastria assessed from the serosal recording and the EGG during the 3 different periods of the recording were 16.1% vs. 27.8%, r=0.92, p
4460 SPATIO-TEMPORAL CHARACTERISTIC OF GASTRIC SLOW WAVE PROPAGATION IN DOGS. Zhishun Wang, Hui Ouyang, Jiande Chen, Univ of Texas Med Branch, Galveston, TX. It has long been accepted that the gastric slow wave propagates distally with an increasing velocity. However, our preliminary observations did not seem to support such a notion. Therefore, the aim of this study was to quantitatively compute the propagation velocity of the gastric slow wave and its temporal variations during different phases of the migrating motor complex (MMC). Methods: The study was performed in 7 healthy female hound dogs (l4-22kg) surgically implanted with eight pairs of bipolar electrodes on the gastric serosa. The eight-channel gastric myoelectrical activity (GMA) was recorded for three hours to assure that one complete cycle of the MMC could be acquired. The previously developed spike detection software was used to accurately extract spike activity to identify different phases of the MMC. After the phase identification, the phase shift of gastric slow waves between two adjacent channels from the proximal to distal was computed. Results: I). Temporal characteristics: The propagation velocity was fastest during Phase III. The phase shift in the distal antrum was 1.45::':0.74s, 1.28::':0.45s and 1.09::':0.44s during phases I, II and III, respectively (phase I vs. III, p<0.05). 2). Spatial characteristics: The propagation velocity of the gastric slow wave increased in a piece-wise nonlinear fashion. The propagation velocity was lowest in the middle part of the stomach. Phase shift in the middle (about 8cm from the pylorus) part of the stomach was significantly larger than that in the most proximal part during phase I ( 3.43 ::': 0.54s vs 2.39 :!: 0.40, p<0.OO3). The results were similar during phases II and III. Phase shift in the most distal part was significantly smaller than that the most proximal part: 1.45 ± 0.74 vs 2.39 ± 0.40, p
a bolus of 0.025 Ulkg) in 7 dogs. Visual and computerized analyses were performed. Results: I) Origin of dysrhythmias. A total 577 min of bradygastria and 20I min of tachygastria were observed in the recordings. A majority of bradygastria was originated in the proximal stomach, 80.5::':9.4%, compared with 8.6::':8.6% originated in the distal antrum (p
4458 GASTRIC DYSRHYTHMIA IS INDICATIVE OF GASTRIC ANTRAL HYPOMOTILITY. Liwei Qian, Zhishun Wang, Jiande Chen, Univ of Texas Med Branch, Galveston, TX. Gastric myoelectrical dysrhythmia has been frequently reported in patients with gastric motor disorders, indirectly suggesting an association of gastric dysrhythmia with dis-motility. The aim of this study was to investigate the direct correlation of gastric dysrhythmia with gastric muscle tone in dogs. Methods: Five healthy female hound dogs (15-22 kg) were implanted with 4 pairs of serosal electrodes along the greater curvature of the stomach at an interval of 4 em with the most distal pair 2 cm above the pylorus. A strain gauge (SG) was sutured on the serosal wall parallel to the most distal pair of electrodes. After the dogs were completely recovered, gastric myoelectrical activity (GMA) and (SG) signal were recorded for 80 min in the fasting state in a few sessions. Medical intervention (vasopressin: 0.5 Ulkg infused over 20 min or glucagon O.1Ulkg infused over 40min plus a bolus of 0.025 Ulkg) was performed after 20-min baseline to induce gastric dysrhythmia. Computerized spectral analysis was applied to calculate the percentage of regular slow waves from the distal channel. The energy of the strain gauge signal was derived by calculating the area under the curve. Results: I) The SG energy was significantly decreased during the 20/40min infusion of either vasopressin/glucagon. The Total energy was 48.4 ::': 1.3 dB at baseline. and decreased to 36.6 ::': 4.5 dB, 44.5 ::': 4.3 dB, 45.8 ::': 1.9 dB during the following three 20-min periods with and after the infusion (p<0.05). 2) The regularity of GMA was 90.1::': 5 % at baseline, reduced to 13.9 ::': 3.9%, and 52.2 ::': 6.4 % during the following two 20-min periods with and after infusion (p
4459
CAPABILITIES AND LIMITATIONS OF ELECTROGASTROGRAM IN THE DETECTION OF NORMAL GASTRIC SLOW WAVE AND GASTRIC DYSRHYTHMIAS. Zhishun Wang, Liwei Qian, Tatsuyuki Ueno, Hui Ouyang, Jiande Chen, Univ of Texas Moo Branch, Galveston, TX. Electrogastrography (EGG) has been widely used in the detection of gastric dysrhythmias in patients with motility disorders. While studies have been
AGAA851
performed to confirm that 3 cycles/min (cpm) waves in the EGG are of gastric origin, little is known on the accuracy of the EGG in the detection of gastric dysrhythmias. The aim of this study was to quantitatively assess the capabilities and limitations of the EGG in the detection of gastric dysrhythmias. Methods: The study was performed in 5 healthy female hound dogs (14-19kg) surgically implanted with four pairs of bipolar electrodes on gastric serosa. After the dogs were completely recovered from surgery. the study was performed in the fasting state using the following protocol: 20 min baseline, 20 min vasopressin infusion (0.5u/kg, in 20ml saline) and 40 min recovery. Four channels of bipolar surface electrodes were placed on abdominal skin over the stomach. Spectral and cross-spectral analysis methods developed in our laboratory were applied to compute the percentage of regular slow waves and slow wave coupling from both the serosal and surface recordings. Results: I) The EGG was capable of detecting the percentage of normal slow waves accurately in the different periods of the experiment (serosal vs. EGG, baseline: 79.8% vs. 70.4%, r=0.95, p<0.02; infusion: 32.9% vs. 35.6%, r=0.95, p<0.02; recovery: 61.0% vs. 52.9%, r=0.91, p<0.04). It was also able to detect the slow wave coupling. 2) Similarly, the EGG was able to accurately detect bradygastria. The percentages of bradygastria assessed from the serosal recording and the EGG during the 3 different periods of the recording were 16.1% vs. 27.8%, r=0.92, p
4460 SPATIO-TEMPORAL CHARACTERISTIC OF GASTRIC SLOW WAVE PROPAGATION IN DOGS. Zhishun Wang, Hui Ouyang, Jiande Chen, Univ of Texas Med Branch, Galveston, TX. It has long been accepted that the gastric slow wave propagates distally with an increasing velocity. However, our preliminary observations did not seem to support such a notion. Therefore, the aim of this study was to quantitatively compute the propagation velocity of the gastric slow wave and its temporal variations during different phases of the migrating motor complex (MMC). Methods: The study was performed in 7 healthy female hound dogs (l4-22kg) surgically implanted with eight pairs of bipolar electrodes on the gastric serosa. The eight-channel gastric myoelectrical activity (GMA) was recorded for three hours to assure that one complete cycle of the MMC could be acquired. The previously developed spike detection software was used to accurately extract spike activity to identify different phases of the MMC. After the phase identification, the phase shift of gastric slow waves between two adjacent channels from the proximal to distal was computed. Results: I). Temporal characteristics: The propagation velocity was fastest during Phase III. The phase shift in the distal antrum was 1.45::':0.74s, 1.28::':0.45s and 1.09::':0.44s during phases I, II and III, respectively (phase I vs. III, p<0.05). 2). Spatial characteristics: The propagation velocity of the gastric slow wave increased in a piece-wise nonlinear fashion. The propagation velocity was lowest in the middle part of the stomach. Phase shift in the middle (about 8cm from the pylorus) part of the stomach was significantly larger than that in the most proximal part during phase I ( 3.43 ::': 0.54s vs 2.39 :!: 0.40, p<0.OO3). The results were similar during phases II and III. Phase shift in the most distal part was significantly smaller than that the most proximal part: 1.45 ± 0.74 vs 2.39 ± 0.40, p