{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T03:46:50Z","timestamp":1778212010733,"version":"3.51.4"},"posted":{"date-parts":[[2026,1,12]]},"group-title":"Cardiovascular Medicine","reference-count":31,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T00:00:00Z","timestamp":1768176000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,1,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:sec>\n                  <jats:title>Aims<\/jats:title>\n                  <jats:p>Left bundle branch block (LBBB) is associated with mechanical dyssynchrony, heterogeneous perfusion, and adverse left ventricular (LV) remodeling. However, not all patients with LBBB develop cardiomyopathy, and dyssynchrony can occur without conduction defects. The role of microvascular dysfunction remains uncertain. We aimed to assess how mechanical dyssynchrony and perfusion heterogeneity relate to LV remodeling and function in patients with and without LBBB.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Methods and results<\/jats:title>\n                  <jats:p>\n                    We retrospectively analyzed 233 patients with isolated LBBB and 932 matched controls who underwent PET myocardial perfusion imaging, assessing mechanical dyssynchrony (phase entropy), myocardial blood flow (MBF), coronary vascular resistance (CVR), myocardial flow reserve (MFR), septal-to-lateral MBF ratio (SLR) for perfusion heterogeneity, LV volumes, and ejection fraction (EF). Compared to controls, patients with LBBB had greater dyssynchrony (56% vs. 40%), larger LV volumes, and lower EF (54% vs. 67%) (all\n                    <jats:italic>p<\/jats:italic>\n                    &lt;0.001), and had higher stress CVR (37 vs. 34 mmHg\/mL\u00b7min\u207b\u00b9\u00b7g\u207b\u00b9), lower stress MBF (2.4 vs. 2.6 mL\/min\/g), reduced MFR (2.4 vs. 2.6), and lower SLR (0.95 vs. 1.00) (all\n                    <jats:italic>p<\/jats:italic>\n                    &lt;0.05).\n                  <\/jats:p>\n                  <jats:p>\n                    Among patients with dyssynchrony, SLR&lt;1.0 identified those with more adverse remodeling. In multivariable regression, phase entropy and SLR independently predicted LV volumes and EF, with adverse effects of SLR reduction amplified in LBBB (interaction\n                    <jats:italic>p<\/jats:italic>\n                    &lt;0.01). In the Cox proportional hazards analysis, phase entropy (HR:1.02,\n                    <jats:italic>p<\/jats:italic>\n                    =0.01), MFR (HR:0.62,\n                    <jats:italic>p<\/jats:italic>\n                    &lt;0.001), and LVEF (HR:0.97,\n                    <jats:italic>p<\/jats:italic>\n                    &lt;0.001) were independently associated with mortality and heart failure hospitalization, whereas LBBB was not.\n                  <\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>Mechanical dyssynchrony and perfusion heterogeneity independently predict adverse LV remodeling, irrespective of LBBB. Integrated imaging enhances cardiomyopathy stratification.<\/jats:p>\n                <\/jats:sec>","DOI":"10.64898\/2026.01.09.26343726","type":"posted-content","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T16:50:19Z","timestamp":1768236619000},"source":"Crossref","is-referenced-by-count":1,"title":["Mechanical Dyssynchrony and Perfusion Heterogeneity Predict Adverse LV Remodeling in Patients with and without LBBB"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9899-1612","authenticated-orcid":false,"given":"Simone Cristina","family":"Soares Brand\u00e3o","sequence":"first","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lee","family":"Joseph","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jenifer M.","family":"Brown","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Diana","family":"Lopez","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mark","family":"Lemley","sequence":"additional","affiliation":[{"name":"Artificial Intelligence in Medicine Research Center, Departments of Biomedical Sciences Medicine, and Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Giselle","family":"Ramirez","sequence":"additional","affiliation":[{"name":"Artificial Intelligence in Medicine Research Center, Departments of Biomedical Sciences Medicine, and Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paul","family":"Kavanagh","sequence":"additional","affiliation":[{"name":"Artificial Intelligence in Medicine Research Center, Departments of Biomedical Sciences Medicine, and Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Serge D.","family":"Van Kriekinge","sequence":"additional","affiliation":[{"name":"Artificial Intelligence in Medicine Research Center, Departments of Biomedical Sciences Medicine, and Cardiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joanna","family":"Liang","sequence":"additional","affiliation":[{"name":"Artificial Intelligence in Medicine Research Center, Departments of Biomedical Sciences Medicine, and Cardiology, Cedars-Sinai 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USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jon","family":"Hainer","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sylvain","family":"Carre","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ron","family":"Blankstein","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sharmila","family":"Dorbala","sequence":"additional","affiliation":[{"name":"Division of Cardiovascular Medicine, Brigham and Women\u2019s Hospital, Harvard Medical School, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Viet T.","family":"Le","sequence":"additional","affiliation":[{"name":"Intermountain Medical Center Heart Institute, Murray, UT, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Steve","family":"Mason","sequence":"additional","affiliation":[{"name":"Intermountain Medical Center Heart Institute, Murray, UT, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stacey","family":"Knight","sequence":"additional","affiliation":[{"name":"Intermountain Medical Center Heart Institute, Murray, UT, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Panithaya","family":"Chareonthaitawee","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Samuel","family":"Wopperer","sequence":"additional","affiliation":[{"name":"Department of Cardiovascular 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