Quantification of velocity anisotropy during gastric electrical arrhythmia

Du, Peng; OrGrady, G.; Paskaranandavadivel, Niranchan; Angeli, Timothy R.; Lahr, Christopher J.; Abell, Thomas L.; Cheng, Leo K.; Pullan, Andrew J.

doi:10.1109/iembs.2011.6091092

Cited by 7 publications

(4 citation statements)

References 8 publications

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“…Importantly, these slow wave initiation and conduction abnormalities may often occur within normal frequency ranges, potentially being missed by techniques lacking in spatial resolution, like cutaneous EGG [ 10 , 12 ]. GEMS analyses have also recently been applied to show, for the first time, that high-velocity and high-amplitude activity routinely emerges in association with many dysrhythmic events [ 28 , 29 ]. In future, this finding may help in the localization and treatment of dysrhythmic sources.…”

Section: Discussionmentioning

confidence: 99%

“…In the normal human stomach, for example, HR mapping has recently shown that normal slow wave excitation is characterized by marked velocity and amplitude transitions occuring between the normal pacemaker region and the corpus, and within the gastric antrum [ 8 ]. Abnormally high velocity and amplitude activity has also recently been found to routinely accompany gastric dysrhythmias, and the velocity and amplitude data provided by GEMS can, therefore, assist in identifying and understanding the onset, location and pattern of abnormal events [ 28 , 29 ].…”

Section: Methodsmentioning

confidence: 99%

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The gastrointestinal electrical mapping suite (GEMS): software for analyzing and visualizing high-resolution (multi-electrode) recordings in spatiotemporal detail

et al. 2012

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BackgroundGastrointestinal contractions are controlled by an underlying bioelectrical activity. High-resolution spatiotemporal electrical mapping has become an important advance for investigating gastrointestinal electrical behaviors in health and motility disorders. However, research progress has been constrained by the low efficiency of the data analysis tasks. This work introduces a new efficient software package: GEMS (Gastrointestinal Electrical Mapping Suite), for analyzing and visualizing high-resolution multi-electrode gastrointestinal mapping data in spatiotemporal detail.ResultsGEMS incorporates a number of new and previously validated automated analytical and visualization methods into a coherent framework coupled to an intuitive and user-friendly graphical user interface. GEMS is implemented using MATLAB®, which combines sophisticated mathematical operations and GUI compatibility. Recorded slow wave data can be filtered via a range of inbuilt techniques, efficiently analyzed via automated event-detection and cycle clustering algorithms, and high quality isochronal activation maps, velocity field maps, amplitude maps, frequency (time interval) maps and data animations can be rapidly generated. Normal and dysrhythmic activities can be analyzed, including initiation and conduction abnormalities. The software is distributed free to academics via a community user website and forum (http://sites.google.com/site/gimappingsuite).ConclusionsThis software allows for the rapid analysis and generation of critical results from gastrointestinal high-resolution electrical mapping data, including quantitative analysis and graphical outputs for qualitative analysis. The software is designed to be used by non-experts in data and signal processing, and is intended to be used by clinical researchers as well as physiologists and bioengineers. The use and distribution of this software package will greatly accelerate efforts to improve the understanding of the causes and clinical consequences of gastrointestinal electrical disorders, through high-resolution electrical mapping.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The gastrointestinal electrical mapping suite (GEMS): software for analyzing and visualizing high-resolution (multi-electrode) recordings in spatiotemporal detail

et al. 2012

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“…Amplitudes were calculated by using a peak-trough detection algorithm based on the ‘zero-crossing’ of the first and second-order signal derivatives of each event, and visualized by assigning a color gradient according to magnitude (Figure 1E) 19 . Corpus results (which show consistent velocities and amplitudes in normal circumstances 16 ) were decomposed into longitudinal and circumferential components for comparison as previously described 24 .…”

Section: Methodsmentioning

confidence: 99%

Abnormal Initiation and Conduction of Slow-Wave Activity in Gastroparesis, Defined by High-Resolution Electrical Mapping

et al. 2012

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Background & Aims Interstitial cells of Cajal (ICC) generate slow waves. Disrupted ICC networks and gastric dysrhythmias are each associated with gastroparesis. However, there are no data on the initiation and propagation of slow waves in gastroparesis, because research tools have lacked spatial resolution. We applied high-resolution electrical mapping to quantify and classify gastroparesis slow-wave abnormalities in spatiotemporal detail. Methods Serosal HR mapping was performed, using flexible arrays (256 electrodes; 36 cm2), at stimulator implantation in 12 patients with diabetic or idiopathic gastroparesis. Data were analyzed by isochronal mapping, velocity and amplitude field mapping, and propagation animation. ICC numbers were determined from gastric biopsies. Results Mean ICC counts were reduced in patients with gastroparesis (2.3 vs 5.4 bodies/field; P<.001). Slow-wave abnormalities were detected by HR mapping in 11/12 patients. Several new patterns were observed and classified as ‘abnormal initiation’ (10/12; stable ectopic pacemakers or diffuse focal events; median 3.3 c/min, range 2.1-5.7), or ‘abnormal conduction’ (7/10; reduced velocities or conduction blocks; median 2.9 c/min; range 2.1-3.6). Circumferential conduction emerged during aberrant initiation or incomplete block and was associated with velocity elevation (7.3 vs 2.9 mm s−1; P=.002) and increased amplitudes beyond a low base value (415 vs 170 μV; P=.002). Conclusions HR mapping revealed new categories of abnormal human slow-wave activity. Abnormalities of slow-wave initiation and conduction occur in gastroparesis, often at normal frequency, which could be missed by tests that lack spatial resolution. Irregular initiation, aberrant conduction, and low amplitude activity could contribute to the pathogenesis of gastroparesis.

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“…Accurate determination of slow wave propagation velocities has become a central focus of gastric HR mapping analysis because substantial changes in velocity have been associated with gastric dysrhythmias indicating abnormal circumferentially propagating wavefronts [10]. Identifying velocity features may therefore allow a better understanding of dysrhythmic slow wave propagation and contribute to an improved foundation for clinically diagnosing gastric dysrhythmias using HR mapping.…”

Section: Introductionmentioning

confidence: 99%

An Improved Method for the Estimation and Visualization of Velocity Fields from Gastric High-Resolution Electrical Mapping

Paskaranandavadivel

OrGrady

et al. 2012

IEEE Trans. Biomed. Eng.

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High-resolution (HR) electrical mapping is an important clinical research tool for understanding normal and abnormal gastric electrophysiology. Analyzing velocities of gastric electrical activity in a reliable and accurate manner can provide additional valuable information for quantitatively and qualitatively comparing features across and within subjects, particularly during gastric dysrhythmias. In this study we compared three methods of estimating velocities from HR recordings to determine which method was the most reliable for use with gastric HR electrical mapping. The three methods were i) Simple finite difference ii) Smoothed finite difference and a iii) Polynomial based method. With synthetic data, the accuracy of the simple finite difference method resulted in velocity errors almost twice that of the smoothed finite difference and the polynomial based method, in the presence of activation time error up to 0.5s. With three synthetic cases under various noise types and levels, the smoothed finite difference resulted in average speed error of 3.2% and an average angle error of 2.0° and the polynomial based method had an average speed error of 3.3% and an average angle error of 1.7°. With experimental gastric slow wave recordings performed in pigs, the three methods estimated similar velocities (6.3-7.3 mm/s), but the smoothed finite difference method had a lower standard deviation in its velocity estimate than the simple finite difference and the polynomial based method, leading it to be the method of choice for velocity estimation in gastric slow wave propagation. An improved method for visualizing velocity fields is also presented.

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Quantification of velocity anisotropy during gastric electrical arrhythmia

Cited by 7 publications

References 8 publications

The gastrointestinal electrical mapping suite (GEMS): software for analyzing and visualizing high-resolution (multi-electrode) recordings in spatiotemporal detail

The gastrointestinal electrical mapping suite (GEMS): software for analyzing and visualizing high-resolution (multi-electrode) recordings in spatiotemporal detail

Abnormal Initiation and Conduction of Slow-Wave Activity in Gastroparesis, Defined by High-Resolution Electrical Mapping

An Improved Method for the Estimation and Visualization of Velocity Fields from Gastric High-Resolution Electrical Mapping

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