Dataset Information

A system and method for online high-resolution mapping of gastric slow-wave activity.

ABSTRACT: High-resolution (HR) mapping employs multielectrode arrays to achieve spatially detailed analyses of propagating bioelectrical events. A major current limitation is that spatial analyses must currently be performed "off-line" (after experiments), compromising timely recording feedback and restricting experimental interventions. These problems motivated development of a system and method for "online" HR mapping. HR gastric recordings were acquired and streamed to a novel software client. Algorithms were devised to filter data, identify slow-wave events, eliminate corrupt channels, and cluster activation events. A graphical user interface animated data and plotted electrograms and maps. Results were compared against off-line methods. The online system analyzed 256-channel serosal recordings with no unexpected system terminations with a mean delay 18 s. Activation time marking sensitivity was 0.92; positive predictive value was 0.93. Abnormal slow-wave patterns including conduction blocks, ectopic pacemaking, and colliding wave fronts were reliably identified. Compared to traditional analysis methods, online mapping had comparable results with equivalent coverage of 90% of electrodes, average RMS errors of less than 1 s, and CC of activation maps of 0.99. Accurate slow-wave mapping was achieved in near real-time, enabling monitoring of recording quality and experimental interventions targeted to dysrhythmic onset. This work also advances the translation of HR mapping toward real-time clinical application.

SUBMITTER: Bull SH

PROVIDER: S-EPMC4323276 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

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A system and method for online high-resolution mapping of gastric slow-wave activity.

Bull Simon H SH O'Grady Gregory G Du Peng P Cheng Leo K LK

IEEE transactions on bio-medical engineering 20140520 11

High-resolution (HR) mapping employs multielectrode arrays to achieve spatially detailed analyses of propagating bioelectrical events. A major current limitation is that spatial analyses must currently be performed "off-line" (after experiments), compromising timely recording feedback and restricting experimental interventions. These problems motivated development of a system and method for "online" HR mapping. HR gastric recordings were acquired and streamed to a novel software client. Algorith ...[more]

PMID: 24860024

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Project description:BackgroundGastric contractions are coordinated by slow waves, generated by interstitial cells of Cajal (ICC). Gastric surgery affects slow wave conduction, potentially contributing to postoperative gastric dysfunction. However, the impact of gastric cuts on slow waves has not been comprehensively evaluated. This study aimed to define consequences of surgical excisions on gastric slow waves by applying high-resolution (HR) electrical mapping and in silico modeling.MethodsPatients undergoing gastric stimulator implantation (n = 10) underwent full-thickness stapled excisions (25 × 15 mm, distal corpus) for histological evaluation, enabling HR mapping (256 electrodes; 36 cm(2) ) over and adjacent to excisions. A biophysically based in silico model of bidirectionally coupled ICC networks was developed and applied to investigate the underlying conduction mechanisms and importance of excision orientation.Key resultsNormal gastric slow waves propagated aborally (3.0 ± 0.2 cpm). Excisions induced complete conduction block and wavelets that rotated around blocks, then propagated rapidly circumferentially distal to the blocks (8.5 ± 1.2 vs normal 3.6 ± 0.4 mm/s; p < 0.01). This 'conduction anisotropy' homeostatically restored antegrade propagating gastric wavefronts distal to excisions. Excisions were associated with complex dysrhythmias in five patients: retrograde propagation (3/10), ectopics (3/10), functional blocks (2/10), and collisions (1/10). Simulations demonstrated conduction anisotropy emerged from bidirectional coupling within ICC layers and showed transverse incision length and orientation correlated with the degree of conduction distortion.Conclusions & inferencesOrienting incisions in the longitudinal gastric axis causes least disruption to electrical conduction and motility. However, if transverse incisions are made, a homeostatic mechanism of gastric conduction anisotropy compensates by restoring aborally propagating wavefronts. Complex dysrhythmias accompanying excisions could modify postoperative recovery in susceptible patients.

Project description:New findingsWhat is the central question of this study? This study aimed to provide the first comparison of simultaneous high-resolution mapping of anterior and posterior gastric serosa over sustained periods. What is the main finding and its importance? Episodes of spontaneous gastric slow-wave dysrhythmias increased significantly following intravenous infusion of vasopressin compared with the baseline state. A number of persistent dysrhythmias were defined, including ectopic activation, conduction block, rotor, retrograde and collision/merger of wavefronts. Slow-wave dysrhythmias could occur either simultaneously or independently on the anterior and posterior gastric serosa, and interacted depending on activation-repolarization and frequency dynamics. High-resolution mapping enables mechanistic insights into gastric slow-wave dysrhythmias and is now achieving clinical translation. However, previous studies have focused mainly on dysrhythmias occurring on the anterior gastric wall. The present study simultaneously mapped the anterior and posterior gastric serosa during episodes of dysrhythmias induced by vasopressin to aid understanding of dysrhythmia initiation, maintenance and termination. High-resolution mapping (8 × 16 electrodes on each serosa; 20-74 cm2 ) was performed in anaesthetized dogs. Baseline recordings (21 ± 8 min) were followed by intravenous infusion of vasopressin (0.1-0.5 IU ml-1 at 60-190 ml h-1 ) and further recordings (22 ± 13 min). Slow-wave activation maps, amplitudes, velocity, interval and frequency were calculated, and differences compared between baseline and postinfusion. All dogs demonstrated an increased prevalence of dysrhythmic events following infusion of vasopressin (17 versus 51%). Both amplitude and velocity demonstrated significant differences (baseline versus postinfusion: 3.6 versus 2.2 mV; 7.7 versus 6.5 mm s-1 ; P < 0.05 for both). Dysrhythmias occurred simultaneously or independently on the anterior and posterior serosa, and then interacted according to frequency dynamics. A number of persistent dysrhythmias were compared, including the following: ectopic activation (n = 2 animals), conduction block (n = 1), rotor (n = 2), retrograde (n = 3) and collision/merger of wavefronts (n = 2). We conclude that infusion of vasopressin induces gastric dysrhythmias, which occur across a heterogeneous range of frequencies and patterns. The results demonstrate that different classes of gastric dysrhythmias may arise simultaneously or independently in one or both surfaces of the serosa, then interact according to their relative frequencies. These results will help to inform interpretation of clinical dysrhythmia.

Dataset Information

A system and method for online high-resolution mapping of gastric slow-wave activity.

Publications

A system and method for online high-resolution mapping of gastric slow-wave activity.

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