{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T10:34:23Z","timestamp":1760524463247,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2023,2,10]],"date-time":"2023-02-10T00:00:00Z","timestamp":1675987200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Minnesota Partnership for Biotechnology and Medical Genomics","award":["MNP #21.30"],"award-info":[{"award-number":["MNP #21.30"]}]},{"name":"University of Minnesota","award":["MNP #21.30"],"award-info":[{"award-number":["MNP #21.30"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>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\u20135 Hz, while the upper bound (BP\u00afth) of the BP filter varies from 15 Hz to 50 Hz according to many researchers. This large range of BP\u00afth 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\u00afth\u00a0 using a data-driven approach (DBSCAN clustering) and demonstrated the effects of different BP\u00afth on subsequent DF and MSF analysis of clinically recorded iEGMs from patients with AF. Our results demonstrated that our preprocessing framework with BP\u00afth = 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.<\/jats:p>","DOI":"10.3390\/e25020332","type":"journal-article","created":{"date-parts":[[2023,2,13]],"date-time":"2023-02-13T03:07:57Z","timestamp":1676257677000},"page":"332","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Data-Driven Preprocessing Framework for Atrial Fibrillation Intracardiac Electrocardiogram Analysis"],"prefix":"10.3390","volume":"25","author":[{"given":"Xiangzhen","family":"Kong","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vasanth","family":"Ravikumar","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Siva K.","family":"Mulpuru","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Henri","family":"Roukoz","sequence":"additional","affiliation":[{"name":"Division of Cardiology, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1624-5793","authenticated-orcid":false,"given":"Elena G.","family":"Tolkacheva","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA"},{"name":"Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA"},{"name":"Institute for Engineering in Medicine, University of Minnesota, Minneapolis, MN 55455, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1027","DOI":"10.1161\/CIRCULATIONAHA.117.031431","article-title":"Genetic Predisposition, Clinical Risk Factor Burden, and Lifetime Risk of Atrial Fibrillation","volume":"137","author":"Weng","year":"2018","journal-title":"Circulation"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e006350","DOI":"10.1161\/CIRCEP.118.006350","article-title":"Lifetime Risk of Atrial Fibrillation by Race and Socioeconomic Status: ARIC Study (Atherosclerosis Risk in Communities)","volume":"11","author":"Mou","year":"2018","journal-title":"Circ. Arrhythmia Electrophysiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2071","DOI":"10.1161\/CIR.0000000000000040","article-title":"2014 AHA\/ACC\/HRS guideline for the management of patients with atrial fibrillation: Executive summary: A report of the American College of Cardiology\/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society","volume":"130","author":"January","year":"2014","journal-title":"Circulation"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1045","DOI":"10.1111\/j.1540-8167.1994.tb01146.x","article-title":"Successful catheter ablation of atrial fibrillation","volume":"5","author":"Haissaguerre","year":"1994","journal-title":"J. Cardiovasc. Electrophysiol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1812","DOI":"10.1056\/NEJMoa1408288","article-title":"Approaches to catheter ablation for persistent atrial fibrillation","volume":"372","author":"Verma","year":"2015","journal-title":"N. Engl. J. Med."},{"key":"ref_6","first-page":"3162","article-title":"Intracardiac electrogram envelope detection during atrial fibrillation using fast orthogonal search","volume":"2017","author":"Hashemi","year":"2017","journal-title":"Annu. Int. Conf. IEEE Eng. Med. Biol. Soc."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2394","DOI":"10.1109\/TBME.2010.2055056","article-title":"Wave-direction and conduction-velocity analysis from intracardiac electrograms\u2014A single-shot technique","volume":"57","author":"Weber","year":"2010","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_8","unstructured":"Pollnow, S. (2019). Characterizing Cardiac Electrophysiology during Radiofrequency Ablation an Integrative Ex Vivo, In Silico, and In Vivo Approach, KIT Scientific Publishing."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1109\/EMB-M.2006.250507","article-title":"Processing of intracardiac electrograms in atrial fibrillation. Diagnosis of electropathological substrate of AF","volume":"25","author":"Houben","year":"2006","journal-title":"IEEE Eng. Med. Biol. Mag."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1109\/10.387197","article-title":"A technique for measurement of the extent of spatial organization of atrial activation during atrial fibrillation in the intact human heart","volume":"42","author":"Botteron","year":"1995","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1161\/01.CIR.93.3.513","article-title":"Quantitative assessment of the spatial organization of atrial fibrillation in the intact human heart","volume":"93","author":"Botteron","year":"1996","journal-title":"Circulation"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1186\/s12938-016-0157-2","article-title":"Several insights into the preprocessing of electrograms in atrial fibrillation for dominant frequency analysis","volume":"15","author":"Li","year":"2016","journal-title":"Biomed. Eng. Online"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1111\/pace.12288","article-title":"On the preprocessing of atrial electrograms in atrial fibrillation: Understanding Botteron\u2019s approach","volume":"37","author":"Castells","year":"2014","journal-title":"Pacing Clin. Electrophysiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1161\/CIRCRESAHA.111.300158","article-title":"Rotors and the dynamics of cardiac fibrillation","volume":"112","author":"Pandit","year":"2013","journal-title":"Circ. Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2467","DOI":"10.1109\/TBME.2014.2322515","article-title":"Characterization of radiofrequency ablation lesion development based on simulated and measured intracardiac electrograms","volume":"61","author":"Keller","year":"2014","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1067","DOI":"10.1109\/TBME.2016.2589158","article-title":"Orientation-Independent Catheter-Based Characterization of Myocardial Activation","volume":"64","author":"Deno","year":"2017","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2905","DOI":"10.1109\/TBME.2020.2973471","article-title":"Mapping and Removing the Ventricular Far Field Component in Unipolar Atrial Electrograms","volume":"67","author":"Frisch","year":"2020","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1109\/TBME.2006.883739","article-title":"On computing dominant frequency from bipolar intracardiac electrograms","volume":"54","author":"Fischer","year":"2007","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1161\/CIRCULATIONAHA.104.517011","article-title":"Spectral analysis identifies sites of high-frequency activity maintaining atrial fibrillation in humans","volume":"112","author":"Sanders","year":"2005","journal-title":"Circulation"},{"key":"ref_20","first-page":"729","article-title":"Detection of His-Purkinje Activity from Distant Intracardiac Electrograms","volume":"31","author":"Borowitz","year":"2004","journal-title":"Comput. Cardiol."},{"key":"ref_21","first-page":"5986","article-title":"Evaluation of Multiscale Frequency Approach for Visualizing Rotors in Patients with Atrial Fibrillation","volume":"2018","author":"Ravikumar","year":"2018","journal-title":"Annu. Int. Conf. IEEE Eng. Med. Biol. Soc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"767190","DOI":"10.3389\/fphys.2021.767190","article-title":"Similarity Score for the Identification of Active Sites in Patients with Atrial Fibrillation","volume":"12","author":"Ravikumar","year":"2022","journal-title":"Front. Physiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1268","DOI":"10.1111\/jce.14948","article-title":"Novel mapping techniques for rotor core detection using simulated intracardiac electrograms","volume":"32","author":"Ravikumar","year":"2021","journal-title":"J. Cardiovasc. Electrophysiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1515\/cdbme-2016-0058","article-title":"Preprocessing of unipolar signals acquired by a novel intracardiac mapping system","volume":"2","author":"Huck","year":"2016","journal-title":"Curr. Dir. Biomed. Eng."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Baala Sundaram, D.S., Kapoor, A., Xie, J., Xu, N.C., Krishna Moorthy, P., Balasubramani, R., Shivaram, S., Muthyala, A., and Poigai Arunachalam, S. (2020, January 6\u20139). Comparison of Multiscale Frequency Characteristics of Normal Phonocardiogram With Diseased Heart States. Proceedings of the 2020 Design of Medical Devices Conference, Minneapolis, MN, USA.","DOI":"10.1115\/DMD2020-9090"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.engappai.2018.12.004","article-title":"Multi-lead model-based ECG signal denoising by guided filter","volume":"79","author":"Hao","year":"2019","journal-title":"Eng. Appl. Artif. Intell."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.hrthm.2008.10.024","article-title":"Real-time dominant frequency mapping and ablation of dominant frequency sites in atrial fibrillation with left-to-right frequency gradients predicts long-term maintenance of sinus rhythm","volume":"6","author":"Atienza","year":"2009","journal-title":"Heart Rhythm."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1109\/JPROC.2015.2505318","article-title":"Quantitative-Electrogram-Based Methods for Guiding Catheter Ablation in Atrial Fibrillation","volume":"104","author":"Baumert","year":"2016","journal-title":"Proc. IEEE"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Knutsson, H., Westin, C., and Granlund, G.H. (1994, January 13\u201316). Local multiscale frequency and bandwidth estimation. Proceedings of the 1st International Conference on Image Processing, Austin, TX, USA.","DOI":"10.1109\/ICIP.1994.413270"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"020948","DOI":"10.1115\/1.4033148","article-title":"Novel Multiscale Frequency Approach to Identify the Pivot Point of the Rotor","volume":"10","author":"Arunachalam","year":"2016","journal-title":"J. Med. Devices Trans. ASME"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1016\/j.jacc.2012.05.022","article-title":"Treatment of atrial fibrillation by the ablation of localized sources: CONFIRM (Conventional Ablation for Atrial Fibrillation with or without Focal Impulse and Rotor Modulation) trial","volume":"60","author":"Narayan","year":"2012","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"586","DOI":"10.1016\/j.hrthm.2010.01.010","article-title":"The temporal variability of dominant frequency and complex fractionated atrial electrograms constrains the validity of sequential mapping in human atrial fibrillation","volume":"7","author":"Habel","year":"2010","journal-title":"Heart Rhythm."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1161\/CIRCEP.112.976654","article-title":"Bipolar electrogram shannon entropy at sites of rotational activation: Implications for ablation of atrial fibrillation","volume":"6","author":"Ganesan","year":"2013","journal-title":"Circ. Arrhythmia Electrophysiol."},{"key":"ref_34","first-page":"497","article-title":"Kurtosis as a statistical approach to identify the pivot point of the rotor","volume":"2016","author":"Arunachalam","year":"2016","journal-title":"Annu. Int. Conf. IEEE Eng. Med. Biol. Soc."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1109\/TBME.2017.2763460","article-title":"Novel Quantitative Analytical Approaches for Rotor Identification and Associated Implications for Mapping","volume":"65","author":"Annoni","year":"2018","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_36","unstructured":"Dastagir, N., Li, X., Paggi, T., Aktiia, A., and Vanheusden, F.J. (2015). Effects of Filtering Atrial Electrograms on the Relationship of Phase and Dominant Frequency, Atrial Signals."},{"key":"ref_37","unstructured":"Sakwan, N.D. (2017). Phase-and Frequency-Domain Analysis of the Intracardiac Signals of Persistent Atrial Fibrillation in Humans, University of Leicester."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2044","DOI":"10.1016\/j.jacc.2003.12.054","article-title":"A new approach for catheter ablation of atrial fibrillation: Mapping of the electrophysiologic substrate","volume":"43","author":"Nademanee","year":"2004","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1038\/415219a","article-title":"New ideas about atrial fibrillation 50 years on","volume":"415","author":"Nattel","year":"2002","journal-title":"Nature"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1401","DOI":"10.1016\/j.jacc.2005.10.071","article-title":"Frequency analysis in different types of paroxysmal atrial fibrillation","volume":"47","author":"Lin","year":"2006","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"79","DOI":"10.3389\/fcvm.2018.00079","article-title":"Regional Dominant Frequency: A New Tool for Wave Break Identification During Atrial Fibrillation","volume":"5","author":"Shariat","year":"2018","journal-title":"Front. Cardiovasc. Med."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Duan, L., Xiong, D., Lee, J., and Guo, F. (2006, January 8\u201311). A Local Density Based Spatial Clustering Algorithm with Noise. Proceedings of the 2006 IEEE International Conference on Systems, Man and Cybernetics, Taipei, Taiwan.","DOI":"10.1109\/ICSMC.2006.384769"},{"key":"ref_43","unstructured":"Andoni, A., Mit, P.I., and Krauthgamer, R. (2008, January 20\u201322). Earth mover distance over high-dimensional spaces. Proceedings of the nineteenth annual ACM-SIAM symposium on Discrete algorithms (SODA \u201908), Society for Industrial and Applied Mathematics, San Francisco, CA, USA."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1145\/3068335","article-title":"DBSCAN Revisited: Why and How You Should (Still) Use DBSCAN","volume":"42","author":"Schubert","year":"2017","journal-title":"ACM Trans. Database Syst."},{"key":"ref_45","unstructured":"Ester, M., Kriegel, H.P., Sander, J., and Xu, X. (1996, January 2\u20134). A density-based algorithm for discovering clusters in large spatial databases with noise. Proceedings of the Second International Conference on Knowledge Discovery and Data Mining (KDD\u201996), Portland, OR, USA."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1080\/01969727308546046","article-title":"A Fuzzy Relative of the ISODATA Process and Its Use in Detecting Compact Well-Separated Clusters","volume":"3","author":"Dunn","year":"1973","journal-title":"J. Cybern."},{"key":"ref_47","unstructured":"(2022, November 08). Julian Ramos, Dunn\u2019s Index. Available online: https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/27859-dunn-s-index."},{"key":"ref_48","unstructured":"(2022, November 08). Dmitry Kaplan, Knee Point. Available online: https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/35094-knee-point."}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/2\/332\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:30:56Z","timestamp":1760121056000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/2\/332"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,10]]},"references-count":48,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["e25020332"],"URL":"https:\/\/doi.org\/10.3390\/e25020332","relation":{},"ISSN":["1099-4300"],"issn-type":[{"type":"electronic","value":"1099-4300"}],"subject":[],"published":{"date-parts":[[2023,2,10]]}}}