{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T23:28:34Z","timestamp":1792452514995,"version":"4.5.0"},"reference-count":34,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T00:00:00Z","timestamp":1778630400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cardiovasc. Med."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Eosinophilic myocarditis (EM) is a rare and potentially life-threatening inflammatory heart disease. Diagnosis is frequently delayed because clinical presentations are heterogeneous, early cardiovascular magnetic resonance (CMR) lacks a pathognomonic pattern, and endomyocardial biopsy (EMB) is often performed late or after glucocorticoid exposure. A further pitfall is assuming that EM can be excluded in the absence of peripheral eosinophilia or overt extracardiac disease. Delayed recognition may result in irreversible myocardial injury, endomyocardial fibrosis and adverse clinical outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case summary<\/jats:title>\n                    <jats:p>We report four cases of EM managed at our institution, each exemplifying a distinct diagnostic and therapeutic challenge. The first case was initially misclassified as apical hypertrophic cardiomyopathy on transthoracic echocardiography and CMR due to apical pseudo-hypertrophy, later evolving into endomyocardial fibrosis with severe mitral regurgitation requiring surgical annuloplasty, without clinical evidence of systemic disease. The second case was consistent with anti-neutrophil cytoplasmic antibodies (ANCA)-negative EGPA complicated by myocarditis; prolonged glucocorticoid exposure likely attenuated peripheral eosinophilia and masked eosinophils on EMB. The third case was initially classified as lymphocytic myocarditis based on an EMB performed under glucocorticoids, with eosinophilic infiltration and Loeffler endocarditis uncovered on repeat biopsy after steroid tapering. The fourth case presented with ST-segment elevation myocardial infarction secondary to coronary embolism in the setting of idiopathic hypereosinophilia. Across cases, we detail the diagnostic workup, emphasizing the complementary role of multimodality imaging and EMB, and outline therapeutic strategies, combining conventional immunosuppression with emerging targeted therapies against the interleukin-5 pathway.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>EM may present as an isolated, organ-specific cardiac disease in the absence of extracardiac involvement or peripheral eosinophilia, with a time-dependent prognosis. Diagnostic pitfalls frequently arise from reliance on non-invasive imaging alone and from smoldering disease course, particularly when chronic glucocorticoid therapy masks both clinical and histological features. Clinicians should maintain a high level of suspicion for EM diagnosis, even in absence of peripheral hypereosinophilia and if endomyocardial biopsy is obtained after acute or chronic steroid therapy, and consider possible thromboembolic complications, such as coronary artery embolization.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fcvm.2026.1818565","type":"journal-article","created":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T05:56:00Z","timestamp":1778651760000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Eosinophilic myocarditis: diagnostic pitfalls and therapeutic challenges. A Case Series"],"prefix":"10.3389","volume":"13","author":[{"given":"A. S.","family":"Giordani","sequence":"first","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Menghi","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Baritussio","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F.","family":"Scognamiglio","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Vicenzetto","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.","family":"Castegnaro","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Marcolongo","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G.","family":"Toscano","sequence":"additional","affiliation":[{"name":"Cardiac Surgery, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F.","family":"Chieco Bianchi","sequence":"additional","affiliation":[{"name":"Respiratory Medicine, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"L.","family":"Iorio","sequence":"additional","affiliation":[{"name":"Rheumatology, Department of Medicine, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Padoan","sequence":"additional","affiliation":[{"name":"Rheumatology, Department of Medicine, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.","family":"De Gaspari","sequence":"additional","affiliation":[{"name":"Cardiovascular Pathology, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S.","family":"Rizzo","sequence":"additional","affiliation":[{"name":"Cardiovascular Pathology, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Basso","sequence":"additional","affiliation":[{"name":"Cardiovascular Pathology, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A. L. P.","family":"Caforio","sequence":"additional","affiliation":[{"name":"Cardiology and Cardioimmunology Laboratory, Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padova","place":["Padova, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,13]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"656","DOI":"10.23736\/S2724-5683.23.06297-X","article-title":"Eosinophilic myocarditis: from etiology to diagnostics and therapy","volume":"72","author":"Russo","year":"2024","journal-title":"Minerva Cardiol Angiol"},{"key":"B2","doi-asserted-by":"publisher","first-page":"2363","DOI":"10.1016\/j.jacc.2017.09.023","article-title":"Eosinophilic myocarditis: characteristics, treatment, and outcomes","volume":"70","author":"Brambatti","year":"2017","journal-title":"J Am Coll Cardiol"},{"key":"B3","doi-asserted-by":"publisher","first-page":"378","DOI":"10.1038\/s41584-023-00958-w","article-title":"Evidence-Based guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis","volume":"19","author":"Emmi","year":"2023","journal-title":"Nat Rev Rheumatol"},{"key":"B4","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1016\/j.jacc.2019.04.063","article-title":"Fulminant versus acute nonfulminant myocarditis in patients with left ventricular systolic dysfunction","volume":"74","author":"Ammirati","year":"2019","journal-title":"J Am Coll Cardiol"},{"key":"B5","doi-asserted-by":"publisher","first-page":"e229","DOI":"10.1016\/j.jaad.2010.11.057","article-title":"A review of DRESS-associated myocarditis","volume":"66","author":"Bourgeois","year":"2012","journal-title":"J Am Acad Dermatol"},{"key":"B6","doi-asserted-by":"publisher","first-page":"634","DOI":"10.1161\/CIRCULATIONAHA.125.074797","article-title":"Natural history of patients with histologically proven acute eosinophilic myocarditis","volume":"153","author":"Ammirati","year":"2026","journal-title":"Circulation"},{"key":"B7","doi-asserted-by":"publisher","first-page":"2636","DOI":"10.1093\/eurheartj\/eht210","article-title":"Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology working group on myocardial and pericardial diseases","volume":"34","author":"Caforio","year":"2013","journal-title":"Eur Heart J"},{"key":"B8","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1186\/s12968-023-00979-0","article-title":"Cardiac magnetic resonance in histologically proven eosinophilic myocarditis","volume":"25","author":"P\u00f6yh\u00f6nen","year":"2023","journal-title":"J Cardiovasc Magn Reson"},{"key":"B9","doi-asserted-by":"publisher","first-page":"5110","DOI":"10.1093\/eurheartj\/ehad707","article-title":"Fulminant myocarditis proven by early biopsy and outcomes","volume":"44","author":"Huang","year":"2023","journal-title":"Eur Heart J"},{"key":"B10","doi-asserted-by":"publisher","first-page":"104","DOI":"10.1007\/BF02481750","article-title":"Improvement of eosinophilic heart disease after steroid therapy: successful demonstration by endomyocardial biopsied specimens","volume":"14","author":"Hayashi","year":"1999","journal-title":"Heart Vessels"},{"key":"B11","doi-asserted-by":"publisher","first-page":"486","DOI":"10.1016\/j.amjms.2017.04.002","article-title":"Eosinophilic myocarditis","volume":"354","author":"Cheung","year":"2017","journal-title":"Am J Med Sci"},{"key":"B12","doi-asserted-by":"publisher","first-page":"1995","DOI":"10.1093\/eurheartj\/ehp249","article-title":"Randomized study on the efficacy of immunosuppressive therapy in patients with virus-negative inflammatory cardiomyopathy: the TIMIC study","volume":"30","author":"Frustaci","year":"2009","journal-title":"Eur Heart J"},{"key":"B13","doi-asserted-by":"publisher","first-page":"3463","DOI":"10.1093\/eurheartj\/ehac348","article-title":"Immunosuppressive therapy in virus-negative inflammatory cardiomyopathy: 20-year follow-up of the TIMIC trial","volume":"43","author":"Chimenti","year":"2022","journal-title":"Eur Heart J"},{"key":"B14","doi-asserted-by":"publisher","first-page":"1921","DOI":"10.1056\/NEJMoa1702079","article-title":"Mepolizumab or placebo for eosinophilic granulomatosis with polyangiitis","volume":"376","author":"Wechsler","year":"2017","journal-title":"N Engl J Med"},{"key":"B15","doi-asserted-by":"publisher","first-page":"1397","DOI":"10.1016\/j.jaci.2020.08.037","article-title":"Efficacy and safety of mepolizumab in hypereosinophilic syndrome: a phase III, randomized, placebo-controlled trial","volume":"146","author":"Roufosse","year":"2020","journal-title":"J Allergy Clin Immunol"},{"key":"B16","doi-asserted-by":"publisher","first-page":"1940","DOI":"10.1056\/NEJMc2404353","article-title":"Benralizumab versus mepolizumab for eosinophilic granulomatosis with polyangiitis","volume":"390","author":"Wechsler","year":"2024","journal-title":"Reply N Engl J Med"},{"key":"B17","doi-asserted-by":"publisher","first-page":"1421","DOI":"10.1016\/j.jaip.2025.03.016","article-title":"Long-term efficacy and safety of benralizumab treatment for PDGFRA-negative hypereosinophilic syndrome","volume":"13","author":"Kuang","year":"2025","journal-title":"J Allergy Clin Immunol Pract"},{"key":"B18","doi-asserted-by":"publisher","first-page":"2892","DOI":"10.1093\/rheumatology\/keae554","article-title":"Dupilumab for refractory chronic rhinosinusitis in eosinophilic granulomatosis with polyangiitis","volume":"64","author":"Padoan","year":"2025","journal-title":"Rheumatology (Oxford)"},{"key":"B19","doi-asserted-by":"publisher","first-page":"2581812","DOI":"10.1080\/07853890.2025.2581812","article-title":"Long-term effectiveness and safety of benralizumab in EGPA: a 3-year single-center experience","volume":"57","author":"Davanzo","year":"2025","journal-title":"Ann Med"},{"key":"B20","doi-asserted-by":"publisher","first-page":"411","DOI":"10.1016\/j.case.2022.08.001","article-title":"Endomyocardial fibrosis, apical hypertrophy, or both?","volume":"6","author":"Sehly","year":"2022","journal-title":"CASE"},{"key":"B21","doi-asserted-by":"publisher","first-page":"320","DOI":"10.3390\/jcdd12080320","article-title":"Multimodality imaging in eosinophilic myocarditis: a rare cause of heart failure","volume":"12","author":"Viccaro","year":"2025","journal-title":"J Cardiovasc Dev Dis"},{"key":"B22","doi-asserted-by":"publisher","first-page":"3952","DOI":"10.1093\/eurheartj\/ehaf192","article-title":"2025 ESC guidelines for the management of myocarditis and pericarditis","volume":"46","author":"Schulz-Menger","year":"2025","journal-title":"Eur Heart J"},{"key":"B23","doi-asserted-by":"publisher","first-page":"1942","DOI":"10.1016\/j.jaccas.2020.07.046","article-title":"Allergy and the heart: eosinophilic myocarditis with biventricular thrombi","volume":"2","author":"Buchanan","year":"2020","journal-title":"JACC Case Rep"},{"key":"B24","doi-asserted-by":"publisher","first-page":"bcr2016218992","DOI":"10.1136\/bcr-2016-218992","article-title":"Therapeutic effect of anti-IL-5 on eosinophilic myocarditis with large pericardial effusion","volume":"2017","author":"Song","year":"2017","journal-title":"BMJ Case Rep"},{"key":"B25","doi-asserted-by":"publisher","first-page":"376","DOI":"10.1016\/j.jcmg.2022.12.029","article-title":"Diagnostic and prognostic role of cardiac magnetic resonance in MINOCA: systematic review and meta-analysis","volume":"16","author":"Mileva","year":"2023","journal-title":"JACC Cardiovasc Imaging"},{"key":"B26","first-page":"13","article-title":"Phenotypic characterisation of cellular infiltrates in endomyocardial biopsies of heart transplant recipients with diagnosed steroid resistant cellular rejection","volume":"8","author":"Zakliczy\u0144ski","year":"2003","journal-title":"Ann Transplant"},{"key":"B27","doi-asserted-by":"publisher","first-page":"913724","DOI":"10.3389\/fcvm.2022.913724","article-title":"The diagnostic challenge of eosinophilic granulomatosis with polyangiitis presenting as acute eosinophilic myocarditis: case report and literature review","volume":"9","author":"Yamamoto","year":"2022","journal-title":"Front Cardiovasc Med"},{"key":"B28","doi-asserted-by":"publisher","first-page":"685","DOI":"10.1001\/jamacardio.2020.0652","article-title":"Off-label use of direct oral anticoagulants compared with warfarin for left ventricular thrombi","volume":"5","author":"Robinson","year":"2020","journal-title":"JAMA Cardiol"},{"key":"B29","doi-asserted-by":"publisher","first-page":"1676","DOI":"10.1016\/j.jacc.2020.01.057","article-title":"Antithrombotic therapy for patients with left ventricular mural thrombus","volume":"75","author":"Lattuca","year":"2020","journal-title":"J Am Coll Cardiol"},{"key":"B30","doi-asserted-by":"publisher","first-page":"2565","DOI":"10.1016\/S0735-1097(20)33192-2","article-title":"Eosinophilic myocarditis masquerading as acute coronary syndrome, a diagnostic and treatment challenge","volume":"75","author":"Kelling","year":"2020","journal-title":"J Am Coll Cardiol"},{"key":"B31","doi-asserted-by":"publisher","first-page":"3720","DOI":"10.1093\/eurheartj\/ehad191","article-title":"2023 ESC guidelines for the management of acute coronary syndromes","volume":"44","author":"Byrne","year":"2023","journal-title":"Eur Heart J"},{"key":"B32","doi-asserted-by":"publisher","first-page":"ytac047","DOI":"10.1093\/ehjcr\/ytac047","article-title":"A unique case report of relapsing eosinophilic myocarditis causing atrial myopathy and persistent sinus arrest","volume":"6","author":"Huynh","year":"2022","journal-title":"Eur Heart J Case Rep"},{"key":"B33","doi-asserted-by":"publisher","first-page":"ytad090","DOI":"10.1093\/ehjcr\/ytad090","article-title":"Utility of cardiac magnetic resonance imaging in diagnosing eosinophilic myocarditis in a patient recently recovered from COVID-19: a grand round case report","volume":"7","author":"Rao","year":"2023","journal-title":"Eur Heart J Case Rep"},{"key":"B34","doi-asserted-by":"publisher","first-page":"102527","DOI":"10.1016\/j.jaccas.2024.102527","article-title":"Eosinophilic endomyocarditis after COVID-19 infection in a heart transplant recipient","volume":"29","author":"Inglis","year":"2024","journal-title":"JACC Case Rep"}],"container-title":["Frontiers in Cardiovascular Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcvm.2026.1818565\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T05:56:01Z","timestamp":1778651761000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcvm.2026.1818565\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,13]]},"references-count":34,"alternative-id":["10.3389\/fcvm.2026.1818565"],"URL":"https:\/\/doi.org\/10.3389\/fcvm.2026.1818565","relation":{},"ISSN":["2297-055X"],"issn-type":[{"value":"2297-055X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,13]]},"article-number":"1818565"}}