Evaluation of Multiscale Frequency Approach for Visualizing Rotors in Patients with Atrial Fibrillation

Ravikumar, Vasanth; Annoni, Elizabeth M.; Mulpuru, Siva K.; Roukoz, Henri; Tolkacheva, Elena G.

doi:10.1109/embc.2018.8513684

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…Therefore, we obtained 18 values of EMD n ( P , Q ). The value of EMD = 0.2 was considered as a threshold for similarity, i.e., if two approaches have EMD < 0.2 ( Ravikumar et al, 2018 ), they are similar, i.e., they have a strong correlation. The threshold was selected based on the minimal distances between the distributions.…”

Section: Methodsmentioning

confidence: 99%

Similarity Score for the Identification of Active Sites in Patients With Atrial Fibrillation

et al. 2022

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BackgroundAtrial fibrillation (AF) is the most common cardiac arrhythmia and precursor to other cardiac diseases. Catheter ablation is associated with limited success rates in patients with persistent AF. Currently, existing mapping systems fail to identify critical target sites for ablation. Recently, we proposed and validated several individual techniques, such as dominant frequency (DF), multiscale frequency (MSF), kurtosis (Kt), and multiscale entropy (MSE), to identify active sites of arrhythmias using simulated intracardiac electrograms (iEGMs). However, the individual performances of these techniques to identify arrhythmogenic substrates are not reliable.ObjectiveThis study aimed to develop a similarity score using various iEGM analysis techniques to more accurately identify the spatial location of active sites of arrhythmia in patients with AF.MethodsClinical bipolar iEGMs were obtained from patients with AF who underwent either successful (m = 4) or unsuccessful (m = 4) catheter ablation. A similarity score (0–3) was developed via the earth mover’s distance (EMD) approach based on a combination of DF, MSF, MSE, and Kt techniques.ResultsIndividual techniques successfully discriminated between successful and unsuccessful AF ablation patients but were not reliable in identifying active spatial sites of AF. However, the proposed similarity score was able to pinpoint the spatial sites with high values (active AF sites) that were observed only in patients with unsuccessful AF termination, suggesting that these active sites were missed during the ablation procedure.ConclusionArrhythmogenic substrates with abnormal electrical activity are identified in patients with unsuccessful AF termination after catheter ablation, suggesting clinical efficacy of similarity score.

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Section: Methodsmentioning

confidence: 99%

Similarity Score for the Identification of Active Sites in Patients With Atrial Fibrillation

et al. 2022

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“…Thus, in this study, we have presented our approaches as a potential alternative to phase mapping.The substantial value of our results is that the novel approaches can be implemented on the intracardiac EGM signals and still maintains critical performance similar to their previous implementation on fluorescence intensity signals from ex-vivo optical mapping experiments. This, in turn, shows that the proposed techniques do not rely on repolarization information of the electrical signal to pinpoint the rotor and its pivot point location, and therefore can be applied to clinically acquired EGMs 29. The intrinsic differences in signal parameters, such as frequency, entropy, and amplitude, are extracted by our methods to discriminate signals from different EGM locations.…”

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confidence: 88%

“…The preprocessing was based on the previous analysis performed on clinical EGM signals. 29 The distance between the two electrodes for bipolar signals was chosen as 0.5 mm, to maintain a high resolution as compared to that of unipolar signals. Both the EGMs were sampled at 1000 samples per second.…”

Section: Simulated Unipolar and Bipolar Egmsmentioning

confidence: 99%

Novel mapping techniques for rotor core detection using simulated intracardiac electrograms

Ravikumar

Annoni

Parthiban

et al. 2021

Cardiovasc electrophysiol

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Background: Catheter ablation is associated with limited success rates in patients with persistent atrial fibrillation (AF). Currently, existing mapping systems fail to identify critical target sites for ablation. Recently, we proposed and validated several techniques (multiscale frequency [MSF], Shannon entropy [SE], kurtosis [Kt], and multiscale entropy [MSE]) to identify pivot point of rotors using ex-vivo optical mapping animal experiments. However, the performance of these techniques is unclear for the clinically recorded intracardiac electrograms (EGMs), due to the different nature of the signals.Objective: This study aims to evaluate the performance of MSF, MSE, SE, and Kt techniques to identify the pivot point of the rotor using unipolar and bipolar EGMs obtained from numerical simulations.Methods: Stationary and meandering rotors were simulated in a 2D human atria.The performances of new approaches were quantified by comparing the "true" core of the rotor with the core identified by the techniques. Also, the performances of all techniques were evaluated in the presence of noise, scar, and for the case of the multielectrode multispline and grid catheters.Results: Our results demonstrate that all the approaches are able to accurately identify the pivot point of both stationary and meandering rotors from both unipolar and bipolar EGMs. The presence of noise and scar tissue did not significantly affect the performance of the techniques. Finally, the core of the rotors was correctly identified for the case of multielectrode multispline and grid catheter simulations. Conclusion:The core of rotors can be successfully identified from EGMs using novel techniques; thus, providing motivation for future clinical implementations.

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A Data-Driven Preprocessing Framework for Atrial Fibrillation Intracardiac Electrocardiogram Analysis

Kong

Ravikumar

Mulpuru

et al. 2023

Entropy

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Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Signal-processing approaches are widely used for the analysis of intracardiac electrograms (iEGMs), which are collected during catheter ablation from patients with AF. In order to identify possible targets for ablation therapy, dominant frequency (DF) is widely used and incorporated in electroanatomical mapping systems. Recently, a more robust measure, multiscale frequency (MSF), for iEGM data analysis was adopted and validated. However, before completing any iEGM analysis, a suitable bandpass (BP) filter must be applied to remove noise. Currently, no clear guidelines for BP filter characteristics exist. The lower bound of the BP filter is usually set to 3–5 Hz, while the upper bound (BP¯th) of the BP filter varies from 15 Hz to 50 Hz according to many researchers. This large range of BP¯th subsequently affects the efficiency of further analysis. In this paper, we aimed to develop a data-driven preprocessing framework for iEGM analysis, and validate it based on DF and MSF techniques. To achieve this goal, we optimized the BP¯th using a data-driven approach (DBSCAN clustering) and demonstrated the effects of different BP¯th on subsequent DF and MSF analysis of clinically recorded iEGMs from patients with AF. Our results demonstrated that our preprocessing framework with BP¯th = 15 Hz has the best performance in terms of the highest Dunn index. We further demonstrated that the removal of noisy and contact-loss leads is necessary for performing correct data iEGMs data analysis.

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Evaluation of Multiscale Frequency Approach for Visualizing Rotors in Patients with Atrial Fibrillation

Cited by 3 publications

References 15 publications

Similarity Score for the Identification of Active Sites in Patients With Atrial Fibrillation

Similarity Score for the Identification of Active Sites in Patients With Atrial Fibrillation

Novel mapping techniques for rotor core detection using simulated intracardiac electrograms

A Data-Driven Preprocessing Framework for Atrial Fibrillation Intracardiac Electrocardiogram Analysis

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