{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:09:00Z","timestamp":1785424140551,"version":"3.56.0"},"reference-count":25,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T00:00:00Z","timestamp":1780444800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["24-15-00335"],"award-info":[{"award-number":["24-15-00335"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]},{"award":["24-15-00335"],"award-info":[{"award-number":["24-15-00335"]}],"id":[{"id":"https:\/\/ror.org\/03y2gwe85","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Invasive mapping studies have shown that one-third of patients with an electrocardiographic pattern of LBBB have intact left bundle branch block conduction and therefore do not actually have a substrate for resynchronization. We aimed to evaluate the activation pattern among responders and non-responders to CRT in a relatively large patient cohort using noninvasive electrocardiographic imaging (ECGi). Methods: A cohort of 185 patients who underwent CRT implantation were enrolled. ECGi was performed at the same hospitalization during intrinsic rhythm. The earliest and the latest left ventricular (LV) activation sites were analyzed according to the 17-segment American Heart Association model. The echocardiographic response to CRT was defined as a reduction of \u226515% in LV end-systolic volume, and clinical response as an improvement of at least one New York Heart Association class at 12 months from the baseline. Results: The earliest activation in the middle inferoseptal LV segment (No.9) was significantly more prevalent among non-responders. A breakthrough in the remaining septal segments (No.2, 3, 8, or 14) was an independent predictor of both clinical (odds ratio (OR) 3.1 [95% confidence interval (CI): 1.2\u20138.1], p = 0.021) and echocardiographic (OR 5.1 [95% CI: 2.2\u201311.8], p &lt; 0.001) responses to CRT. Other independent predictors of echocardiographic and clinical response to CRT in this study were LV pacing site in the lateral wall and QLV interval. Conclusions: The earliest endocardial activation site in segments 2, 3, 8, or 14 of the LV is an independent intrinsic activation marker associated with CRT response, complementary to intraoperative factors.<\/jats:p>","DOI":"10.3390\/diagnostics16111724","type":"journal-article","created":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T13:46:48Z","timestamp":1780494408000},"page":"1724","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Refining Left Bundle Branch Block Activation Criteria in CRT Candidates: A Noninvasive Electrocardiographic Imaging Study"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1025-3728","authenticated-orcid":false,"given":"Lev","family":"Malishevskii","sequence":"first","affiliation":[{"name":"Almazov National Medical Research Centre, 197341 Saint Petersburg, Russia"},{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4670-5861","authenticated-orcid":false,"given":"Stepan","family":"Zubarev","sequence":"additional","affiliation":[{"name":"Almazov National Medical Research Centre, 197341 Saint Petersburg, Russia"},{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-7853-2332","authenticated-orcid":false,"given":"Anastasia","family":"Bazhutina","sequence":"additional","affiliation":[{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nikita","family":"Markov","sequence":"additional","affiliation":[{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"},{"name":"Department of Mathematics, Mechanics and Computer Science, Ural Federal University, 620002 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6553-9141","authenticated-orcid":false,"given":"Evgeny N.","family":"Mikhaylov","sequence":"additional","affiliation":[{"name":"Almazov National Medical Research Centre, 197341 Saint Petersburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7965-2364","authenticated-orcid":false,"given":"Tatiana","family":"Chumarnaya","sequence":"additional","affiliation":[{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"},{"name":"Department of Mathematics, Mechanics and Computer Science, Ural Federal University, 620002 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2540-6544","authenticated-orcid":false,"given":"Vera","family":"Stepanova","sequence":"additional","affiliation":[{"name":"I.I. Mechnikov North-Western State Medical University, 191015 Saint Petersburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0507-096X","authenticated-orcid":false,"given":"Viktoria","family":"Lebedeva","sequence":"additional","affiliation":[{"name":"Almazov National Medical Research Centre, 197341 Saint Petersburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olga","family":"Solovyova","sequence":"additional","affiliation":[{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"},{"name":"Department of Mathematics, Mechanics and Computer Science, Ural Federal University, 620002 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2334-1663","authenticated-orcid":false,"given":"Dmitry S.","family":"Lebedev","sequence":"additional","affiliation":[{"name":"Almazov National Medical Research Centre, 197341 Saint Petersburg, Russia"},{"name":"Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 620078 Ekaterinburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"914","DOI":"10.1161\/01.CIR.69.5.914","article-title":"Endocardial activation of left bundle branch block","volume":"69","author":"Vassallo","year":"1984","journal-title":"Circulation"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e235","DOI":"10.1161\/CIRCULATIONAHA.108.191095","article-title":"AHA\/ACCF\/HRS recommendations for the standardization and interpretation of the electrocardiogram: Part III: Intraventricular conduction disturbances: A scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: Endorsed by the International Society for Computerized Electrocardiology","volume":"119","author":"Surawicz","year":"2009","journal-title":"Circulation"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3427","DOI":"10.1093\/eurheartj\/ehab364","article-title":"2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy","volume":"42","author":"Glikson","year":"2021","journal-title":"Eur. 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Imaging"}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/11\/1724\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T12:11:57Z","timestamp":1780575117000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/11\/1724"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,3]]},"references-count":25,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["diagnostics16111724"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16111724","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,3]]}}}