{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T02:14:59Z","timestamp":1779243299263,"version":"3.51.4"},"reference-count":53,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,3,12]],"date-time":"2021-03-12T00:00:00Z","timestamp":1615507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000274","name":"British Heart Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000274","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:p><jats:bold>Purpose:<\/jats:bold> Identifying targets for catheter ablation remains challenging in persistent atrial fibrillation (persAF). The dominant frequency (DF) of atrial electrograms during atrial fibrillation (AF) is believed to primarily reflect local activation. Highest DF (HDF) might be responsible for the initiation and perpetuation of persAF. However, the spatiotemporal behavior of DF remains not fully understood. Some DFs during persAF were shown to lack spatiotemporal stability, while others exhibit recurrent behavior. We sought to develop a tool to automatically detect recurrent DF patterns in persAF patients.<\/jats:p><jats:p><jats:bold>Methods:<\/jats:bold> Non-contact mapping of the left atrium (LA) was performed in 10 patients undergoing persAF HDF ablation. 2,048 virtual electrograms (vEGMs, EnSite Array, Abbott Laboratories, USA) were collected for up to 5 min before and after ablation. Frequency spectrum was estimated using fast Fourier transform and DF was identified as the peak between 4 and 10 Hz and organization index (OI) was calculated. The HDF maps were identified per 4-s window and an automated pattern recognition algorithm was used to find recurring HDF spatial patterns. Dominant patterns (DPs) were defined as the HDF pattern with the highest recurrence.<\/jats:p><jats:p><jats:bold>Results:<\/jats:bold> DPs were found in all patients. Patients in atrial flutter after ablation had a single DP over the recorded time period. The time interval (median [IQR]) of DP recurrence for the patients in AF after ablation (7 patients) decreased from 21.1 s [11.8 49.7 s] to 15.7 s [6.5 18.2 s]. The DF inside the DPs presented lower temporal standard deviation (0.18 \u00b1 0.06 Hz vs. 0.29 \u00b1 0.12 Hz, <jats:italic>p<\/jats:italic> &amp;lt; 0.05) and higher OI (0.35 \u00b1 0.03 vs. 0.31 \u00b1 0.04, <jats:italic>p<\/jats:italic> &amp;lt; 0.05). The atrial regions with the highest proportion of HDF region were the septum and the left upper pulmonary vein.<\/jats:p><jats:p><jats:bold>Conclusion:<\/jats:bold> Multiple recurrent spatiotemporal HDF patterns exist during persAF. The proposed method can identify and quantify the spatiotemporal repetition of the HDFs, where the high recurrences of DP may suggest a more organized rhythm. DPs presented a more consistent DF and higher organization compared with non-DPs, suggesting that DF with higher OI might be more likely to recur. Recurring patterns offer a more comprehensive dynamic insight of persAF behavior, and ablation targeting such regions may be beneficial.<\/jats:p>","DOI":"10.3389\/fphys.2021.649486","type":"journal-article","created":{"date-parts":[[2021,3,12]],"date-time":"2021-03-12T07:34:37Z","timestamp":1615534477000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":14,"title":["Automatic Extraction of Recurrent Patterns of High Dominant Frequency Mapping During Human Persistent Atrial Fibrillation"],"prefix":"10.3389","volume":"12","author":[{"given":"Xin","family":"Li","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gavin S.","family":"Chu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tiago P.","family":"Almeida","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Frederique J.","family":"Vanheusden","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jo\u00e3o","family":"Salinet","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nawshin","family":"Dastagir","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Amar R.","family":"Mistry","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zakariyya","family":"Vali","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bharat","family":"Sidhu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter J.","family":"Stafford","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fernando S.","family":"Schlindwein","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"G. Andr\u00e9","family":"Ng","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2021,3,12]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1093\/eurheartj\/17.suppl_C.2","article-title":"Unravelling the electrical mysteries of atrial fibrillation","volume":"17","author":"Allessie","year":"1996","journal-title":"Eur. Heart J"},{"key":"B2","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1161\/CIRCRESAHA.111.255026","article-title":"The role of fibroblasts in complex fractionated electrograms during persistent\/permanent atrial fibrillation: implications for electrogram-based catheter ablation","volume":"110","author":"Ashihara","year":"2012","journal-title":"Circ. Res."},{"key":"B3","doi-asserted-by":"publisher","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":"B4","doi-asserted-by":"publisher","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":"B5","doi-asserted-by":"publisher","first-page":"1024","DOI":"10.1111\/j.1540-8167.2008.01219.x","article-title":"Diagnostic accuracy of a new software for complex fractionated electrograms identification in patients with persistent and permanent atrial fibrillation","volume":"19","author":"Calo","year":"2008","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B6","doi-asserted-by":"publisher","first-page":"1879","DOI":"10.1161\/01.CIR.100.18.1879","article-title":"Initiation of atrial fibrillation by ectopic beats originating from the pulmonary veins: electrophysiological characteristics, pharmacological responses, and effects of radiofrequency ablation","volume":"100","author":"Chen","year":"1999","journal-title":"Circulation"},{"key":"B7","doi-asserted-by":"publisher","first-page":"v1","DOI":"10.1093\/europace\/euv324","article-title":"Young Investigators Competition1Left ventricular lead position, mechanical activation and myocardial scar in relation to the clinical outcome of cardiac resynchronisation therapy: the role of feature-tracking and contrast-enhanced cardiovascular magnetic resonance2Does the haemodynamic improvement of biventricular pacing truly arise from cardiac resynchronisation? quantifying the contribution of av and vv adjustment3Differential relationship of electrical delay with endocardial and epicardial left ventricular leads for cardiac resynchronisation therapy4Characterisation of the persistent af substrate through the assessment of electrophysiologic parameters in the organised vs. disorganised rhythm5Targeting cyclical highest dominant frequency in the ablation of persistent atrial fibrillation6Feasibility of fully mr-guided ablation with active tracking: from pre-clinical to clinical application","volume":"17","author":"Chubb","year":"2016","journal-title":"Europace"},{"key":"B8","doi-asserted-by":"publisher","first-page":"207","DOI":"10.1016\/j.jacep.2016.08.001","article-title":"Identification of repetitive activation patterns using novel computational analysis of multielectrode recordings during atrial fibrillation and flutter in humans","volume":"3","author":"Daoud","year":"2017","journal-title":"JACC Clin. Electrophysiol"},{"key":"B9","doi-asserted-by":"publisher","first-page":"485","DOI":"10.1016\/j.jacc.2006.04.069","article-title":"Validation of the noncontact mapping system in the left atrium during permanent atrial fibrillation and sinus rhythm","volume":"48","author":"Earley","year":"2006","journal-title":"J. Am. Coll. Cardiol"},{"key":"B10","doi-asserted-by":"publisher","first-page":"969","DOI":"10.1109\/10.942586","article-title":"Frequency domain algorithm for quantifying atrial fibrillation organization to increase defibrillation efficacy","volume":"48","author":"Everett","year":"2001","journal-title":"IEEE Trans. Biomed. Eng"},{"key":"B11","doi-asserted-by":"publisher","first-page":"1371","DOI":"10.1093\/europace\/euu389","article-title":"Recurrence of paroxysmal atrial fibrillation after pulmonary vein isolation: is repeat pulmonary vein isolation enough? A prospective, randomized trial","volume":"17","author":"Fichtner","year":"2015","journal-title":"Europace"},{"key":"B12","doi-asserted-by":"publisher","first-page":"375","DOI":"10.1161\/01.CIR.86.2.375","article-title":"Evidence for transient linking of atrial excitation during atrial fibrillation in humans","volume":"86","author":"Gerstenfeld","year":"1992","journal-title":"Circulation"},{"key":"B13","doi-asserted-by":"publisher","first-page":"2968","DOI":"10.1161\/01.CIR.94.11.2968","article-title":"Electrical remodeling in atrial fibrillation. Time course and mechanisms","volume":"94","author":"Goette","year":"1996","journal-title":"Circulation"},{"key":"B14","doi-asserted-by":"publisher","first-page":"997","DOI":"10.1111\/j.1540-8167.2009.01488.x","article-title":"Dominant frequency mapping of atrial fibrillation: comparison of contact and noncontact approaches","volume":"20","author":"Gojraty","year":"2009","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B15","doi-asserted-by":"publisher","first-page":"2649","DOI":"10.1161\/01.CIR.94.10.2649","article-title":"Incomplete reentry and epicardial breakthrough patterns during atrial fibrillation in the sheep heart","volume":"94","author":"Gray","year":"1996","journal-title":"Circulation"},{"key":"B16","doi-asserted-by":"publisher","first-page":"659","DOI":"10.1056\/NEJM199809033391003","article-title":"Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins","volume":"339","author":"Haissaguerre","year":"1998","journal-title":"New Engl. J. Med"},{"key":"B17","doi-asserted-by":"publisher","first-page":"124","DOI":"10.1016\/j.jacep.2017.09.177","article-title":"A novel mapping system for panoramic mapping of the left atrium: application to detect and characterize localized sources maintaining atrial fibrillation","volume":"4","author":"Honarbakhsh","year":"2018","journal-title":"JACC Clin. Electrophysiol"},{"key":"B18","doi-asserted-by":"publisher","first-page":"204","DOI":"10.1016\/S0008-6363(02)00223-7","article-title":"Mother rotors and fibrillatory conduction: a mechanism of atrial fibrillation","volume":"54","author":"Jalife","year":"2002","journal-title":"Cardiovasc. Res"},{"key":"B19","doi-asserted-by":"publisher","first-page":"650","DOI":"10.1161\/CIRCEP.111.967992","article-title":"Spatiotemporal behavior of high dominant frequency during paroxysmal and persistent atrial fibrillation in the human left atrium","volume":"5","author":"Jarman","year":"2012","journal-title":"Circ. Arrhythm. Electrophysiol"},{"key":"B20","doi-asserted-by":"publisher","first-page":"355","DOI":"10.1111\/jce.12352","article-title":"Organizational index mapping to identify focal sources during persistent atrial fibrillation","volume":"25","author":"Jarman","year":"2014","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B21","doi-asserted-by":"publisher","first-page":"869","DOI":"10.3389\/fphys.2020.00869","article-title":"Standardizing single-frame phase singularity identification algorithms and parameters in phase mapping during human atrial fibrillation","volume":"11","author":"Li","year":"","journal-title":"Front. Physiol"},{"key":"B22","doi-asserted-by":"publisher","first-page":"61","DOI":"10.1109\/CIC.2015.7408586","article-title":"Investigation on recurrent high dominant frequency spatiotemporal patterns during persistent atrial fibrillation","volume":"42","author":"Li","year":"2015","journal-title":"Comput. Cardiol"},{"key":"B23","doi-asserted-by":"publisher","first-page":"83","DOI":"10.1016\/j.cmpb.2017.01.011","article-title":"An interactive platform to guide catheter ablation in human persistent atrial fibrillation using dominant frequency, organization and phase mapping","volume":"141","author":"Li","year":"2017","journal-title":"Comput. Methods Programs Biomed"},{"key":"B24","doi-asserted-by":"publisher","first-page":"euaa162","DOI":"10.1093\/europace\/euaa162.013","article-title":"P439Could regional electrogram desynchronization identified using mean phase coherence be potential ablation targets in persistent atrial fibrillation?","volume":"22","author":"Li","year":"","journal-title":"EP Europace"},{"key":"B25","doi-asserted-by":"publisher","first-page":"2631","DOI":"10.1161\/01.CIR.103.21.2631","article-title":"Left-to-right gradient of atrial frequencies during acute atrial fibrillation in the isolated sheep heart","volume":"103","author":"Mansour","year":"2001","journal-title":"Circulation"},{"key":"B26","doi-asserted-by":"publisher","first-page":"200","DOI":"10.1016\/0002-8703(64)90371-0","article-title":"A computer model of atrial fibrillation","volume":"67","author":"Moe","year":"1964","journal-title":"Am. Heart J"},{"key":"B27","doi-asserted-by":"publisher","first-page":"1761","DOI":"10.1016\/j.jacc.2014.02.543","article-title":"Ablation of rotor and focal sources reduces late recurrence of atrial fibrillation compared with trigger ablation alone: extended follow-up of the CONFIRM trial (Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation)","volume":"63","author":"Narayan","year":"2014","journal-title":"J. Am. Coll. Cardiol"},{"key":"B28","doi-asserted-by":"publisher","first-page":"1436","DOI":"10.1016\/j.hrthm.2012.03.055","article-title":"Focal impulse and rotor modulation ablation of sustaining rotors abruptly terminates persistent atrial fibrillation to sinus rhythm with elimination on follow-up: a video case study","volume":"9","author":"Narayan","year":"2012","journal-title":"Heart Rhythm"},{"key":"B29","doi-asserted-by":"publisher","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":"B30","doi-asserted-by":"publisher","first-page":"5","DOI":"10.1177\/107424840300800102","article-title":"Atrial electrophysiology and mechanisms of atrial fibrillation","volume":"8","author":"Nattel","year":"2003","journal-title":"J. Cardiovasc. Pharmacol. Ther."},{"key":"B31","doi-asserted-by":"publisher","first-page":"2027","DOI":"10.1016\/j.hrthm.2014.08.002","article-title":"Electrogram morphology recurrence patterns during atrial fibrillation","volume":"11","author":"Ng","year":"2014","journal-title":"Heart Rhythm"},{"key":"B32","doi-asserted-by":"publisher","first-page":"1077","DOI":"10.1161\/hc0902.104712","article-title":"Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation","volume":"105","author":"Oral","year":"2002","journal-title":"Circulation"},{"key":"B33","doi-asserted-by":"publisher","first-page":"3710","DOI":"10.1161\/CIRCEP.115.003710","article-title":"Left atrial appendage electrical isolation and concomitant device occlusion to treat persistent atrial fibrillation: a first-in-human safety, feasibility, and efficacy study","volume":"9","author":"Panikker","year":"2016","journal-title":"Circ. Arrhythm. Electrophysiol"},{"key":"B34","doi-asserted-by":"publisher","first-page":"266","DOI":"10.1111\/j.1540-8167.2008.01321.x","article-title":"Electrophysiologic characteristics of complex fractionated atrial electrograms in patients with atrial fibrillation","volume":"20","author":"Park","year":"2009","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B35","doi-asserted-by":"publisher","first-page":"e005858","DOI":"10.1161\/CIRCEP.117.005858","article-title":"Rotors detected by phase analysis of filtered, epicardial atrial fibrillation electrograms colocalize with regions of conduction block","volume":"11","author":"Podziemski","year":"2018","journal-title":"Circ. Arrhythm. Electrophysiol"},{"key":"B36","doi-asserted-by":"publisher","first-page":"613","DOI":"10.1111\/j.1540-8167.2008.01189.x","article-title":"Prospective study of atrial fibrillation termination during ablation guided by automated detection of fractionated electrograms","volume":"19","author":"Porter","year":"2008","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B37","doi-asserted-by":"publisher","first-page":"e005008","DOI":"10.1161\/CIRCEP.117.005008","article-title":"Technical considerations on phase mapping for identification of atrial reentrant activity in direct- and inverse-computed electrograms","volume":"10","author":"Rodrigo","year":"2017","journal-title":"Circ. Arrhythm. Electrophysiol"},{"key":"B38","doi-asserted-by":"publisher","first-page":"156","DOI":"10.1016\/j.hrthm.2008.10.046","article-title":"Effect of pulmonary vein isolation on the distribution of complex fractionated electrograms in humans","volume":"6","author":"Roux","year":"2009","journal-title":"Heart Rhythm"},{"key":"B39","doi-asserted-by":"publisher","first-page":"1269","DOI":"10.1016\/j.hrthm.2017.04.031","article-title":"Propagation of meandering rotors surrounded by areas of high dominant frequency in persistent atrial fibrillation","volume":"14","author":"Salinet","year":"2017","journal-title":"Heart Rhythm"},{"key":"B40","doi-asserted-by":"publisher","first-page":"371","DOI":"10.1111\/jce.12331","article-title":"Distinctive patterns of dominant frequency trajectory behavior in drug-refractory persistent atrial fibrillation: preliminary characterization of spatiotemporal instability","volume":"25","author":"Salinet","year":"2014","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B41","doi-asserted-by":"publisher","first-page":"1381","DOI":"10.1007\/s11517-013-1071-4","article-title":"Analysis of QRS-T subtraction in unipolar atrial fibrillation electrograms","volume":"51","author":"Salinet","year":"2013","journal-title":"Med. Biol. Eng. Comput"},{"key":"B42","doi-asserted-by":"publisher","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":"B43","doi-asserted-by":"publisher","first-page":"887","DOI":"10.1161\/01.CIR.98.9.887","article-title":"Simultaneous endocardial mapping in the human left ventricle using a noncontact catheter - comparison of contact and reconstructed electrograms during sinus rhythm","volume":"98","author":"Schilling","year":"1998","journal-title":"Circulation"},{"key":"B44","doi-asserted-by":"publisher","first-page":"1039","DOI":"10.1111\/j.1540-8167.2007.00930.x","article-title":"Radiofrequency ablation of complex fractionated atrial electrograms (CFAE): preferential sites of acute termination and regularization in paroxysmal and persistent atrial fibrillation","volume":"18","author":"Schmitt","year":"2007","journal-title":"J. Cardiovasc. Electrophysiol"},{"key":"B45","doi-asserted-by":"publisher","first-page":"171","DOI":"10.1016\/j.jacep.2019.09.012","article-title":"Validation of dipole density mapping during atrial fibrillation and sinus rhythm in human left atrium","volume":"6","author":"Shi","year":"2020","journal-title":"JACC Clin. Electrophysiol"},{"key":"B46","doi-asserted-by":"publisher","first-page":"1003","DOI":"10.1016\/j.jacc.2007.10.056","article-title":"Characterization of electrograms associated with termination of chronic atrial fibrillation by catheter ablation","volume":"51","author":"Takahashi","year":"2008","journal-title":"J. Am. Coll. Cardiol"},{"key":"B47","doi-asserted-by":"publisher","first-page":"570","DOI":"10.1111\/j.1540-8159.2004.00489.x","article-title":"Noncontact mapping of the left ventricle: insights from validation with transmural contact mapping","volume":"27","author":"Thiagalingam","year":"2004","journal-title":"Pace"},{"key":"B48","doi-asserted-by":"publisher","first-page":"217","DOI":"10.1016\/j.jacep.2016.09.017","article-title":"CARTOFINDER: Can it \u201cFind\u201d Rotors in Atrial Fibrillation?","volume":"3","author":"Tomassoni","year":"2017","journal-title":"JACC Clin. Electrophysiol"},{"key":"B49","doi-asserted-by":"publisher","first-page":"231","DOI":"10.2174\/157340312803217229","article-title":"Frequency domain mapping of atrial fibrillation - methodology, experimental data and clinical implications","volume":"8","author":"Traykov","year":"2012","journal-title":"Curr. Cardiol. Rev"},{"key":"B50","doi-asserted-by":"publisher","first-page":"v112","DOI":"10.1093\/europace\/eus279","article-title":"Atrial septal pacing for the termination of atrial fibrillation: study in a biophysical model of human atria","volume":"14","author":"Uldry","year":"2012","journal-title":"Europace"},{"key":"B51","doi-asserted-by":"publisher","first-page":"105","DOI":"10.1161\/CIRCEP.110.853804","article-title":"Phase mapping of cardiac fibrillation","volume":"3","author":"Umapathy","year":"2010","journal-title":"Circ. Arrhythm. Electrophysiol"},{"key":"B52","doi-asserted-by":"publisher","first-page":"1954","DOI":"10.1161\/01.CIR.92.7.1954","article-title":"Atrial-fibrillation begets atrial-fibrillation - a study in awake chronically instrumented goats","volume":"92","author":"Wijffels","year":"1995","journal-title":"Circulation"},{"key":"B53","doi-asserted-by":"publisher","first-page":"859","DOI":"10.1111\/j.1540-8167.2000.tb00064.x","article-title":"Atrial flutter and atrial fibrillation: two sides of a coin or one coin?","volume":"11","author":"Winter","year":"2000","journal-title":"J. Cardiovasc. Electrophysiol."}],"container-title":["Frontiers in Physiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2021.649486\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,3,12]],"date-time":"2021-03-12T07:34:39Z","timestamp":1615534479000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2021.649486\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,12]]},"references-count":53,"alternative-id":["10.3389\/fphys.2021.649486"],"URL":"https:\/\/doi.org\/10.3389\/fphys.2021.649486","relation":{},"ISSN":["1664-042X"],"issn-type":[{"value":"1664-042X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,12]]},"article-number":"649486"}}