Abstract
BackgroundElectrogram-guided ablation procedures have been proposed as an alternative strategy consisting of either mapping and ablating focal sources or targeting complex fractionated electrograms in atrial fibrillation (AF). However, the incomplete understanding of the mechanism of AF makes difficult the decision of detecting the target sites. To date, feature extraction from electrograms is carried out mostly based on the time-domain morphology analysis and non-linear features. However, their combination has been reported to achieve better performance. Besides, most of the inferring approaches applied for identifying the levels of fractionation are supervised, which lack of an objective description of fractionation. This aspect complicates their application on EGM-guided ablation procedures.MethodsThis work proposes a semi-supervised clustering method of four levels of fractionation. In particular, we make use of the spectral clustering that groups a set of widely used features extracted from atrial electrograms. We also introduce a new atrial-deflection-based feature to quantify the fractionated activity. Further, based on the sequential forward selection, we find the optimal subset that provides the highest performance in terms of the cluster validation. The method is tested on external validation of a labeled database. The generalization ability of the proposed training approach is tested to aid semi-supervised learning on unlabeled dataset associated with anatomical information recorded from three patients.ResultsA joint set of four extracted features, based on two time-domain morphology analysis and two non-linear dynamics, are selected. To discriminate between four considered levels of fractionation, validation on a labeled database performs a suitable accuracy (77.6 %). Results show a congruence value of internal validation index among tested patients that is enough to reconstruct the patterns over the atria to located critical sites with the benefit of avoiding previous manual classification of AF types.ConclusionsTo the best knowledge of the authors, this is the first work reporting semi-supervised clustering for distinguishing patterns in fractionated electrograms. The proposed methodology provides high performance for the detection of unknown patterns associated with critical EGM morphologies. Particularly, obtained results of semi-supervised training show the advantage of demanding fewer labeled data and less training time without significantly compromising accuracy. This paper introduces a new method, providing an objective scheme that enables electro-physiologist to recognize the diverse EGM morphologies reliably.
Highlights
Electrogram-guided ablation procedures have been proposed as an alternative strategy consisting of either mapping and ablating focal sources or target‐ ing complex fractionated electrograms in atrial fibrillation (AF)
Results of clustering For purposes of evaluation of the clustering quality, we carry out training using the selected feature set in two cases: a) External validation using a labeled database with four different classes of atrial EGM. b) Semi-supervised clustering that employs a small amount of labeled data, used in the first training case, to aid semi-supervised clustering on unlabeled dataset, associated with anatomical data, performed separately for each patient
This paper introduces a new method for semi-supervised clustering of fractionated electrograms, providing an objective tool for reliably locating the distribution of different fractionated EGM patterns over the atrial
Summary
Electrogram-guided ablation procedures have been proposed as an alternative strategy consisting of either mapping and ablating focal sources or target‐ ing complex fractionated electrograms in atrial fibrillation (AF). Most of the inferring approaches applied for identifying the levels of fractionation are super‐ vised, which lack of an objective description of fractionation. This aspect complicates their application on EGM-guided ablation procedures. Catheters for radiofrequency ablation are guided inside the heart chambers via cardiac mapping systems [1]. Recent approaches aim at guiding the ablation using electrical signals recorded inside the atria, called electrograms (EGM). These recordings are incorporated into an electroanatomical mapping system to visualize the 3D distribution of the electrical information through the anatomical atrial structure (electroanatomical atrial mapping – EAM).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.