{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T11:50:33Z","timestamp":1753876233446,"version":"3.41.2"},"reference-count":16,"publisher":"Oxford University Press (OUP)","issue":"1","license":[{"start":{"date-parts":[[2024,12,18]],"date-time":"2024-12-18T00:00:00Z","timestamp":1734480000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2024,12,24]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Left bundle branch block (LBBB) is a rare conduction disorder in athletes associated with ventricular dyssynchrony, which can lead to left ventricular systolic dysfunction and exercise intolerance. Inappropriate sinus tachycardia (IST) is characterized by an excessive heart rate (HR) that is not related to physiological needs, often resulting in reduced exercise capacity. Managing these conditions in athletes can be challenging, as standard treatments like beta-blockers and ivabradine, while effective in controlling HR, are described to be associated with a reduction in maximal exercise performance.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Case summary<\/jats:title>\n                  <jats:p>A 50-year-old amateur athlete presented with exercise intolerance, LBBB, and mild dilated cardiomyopathy due to ventricular dyssynchrony. Resting electrocardiogram and 24-h monitoring confirmed IST. Initial cardiopulmonary exercise testing (CPET) off-therapy showed rapid HR increase during exertion, an early plateau in oxygen pulse, and reduced peak oxygen consumption (VO2, 22.1\u2005mL\/kg\/min, 76% of the predicted value). After 1 month of ivabradine 5\u2005mg b.i.d., there was some improvement in these parameters. At the third follow-up, with combined therapy of ivabradine (5\u2005mg b.i.d.) and metoprolol (50\u2005mg b.i.d.), the HR response during exercise normalized, and CPET parameters significantly improved, with peak VO2 reaching 29.2\u2005mL\/kg\/min (101% of the predicted value).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Discussion<\/jats:title>\n                  <jats:p>This case highlights a paradoxical improvement in exercise tolerance and peak VO2 with combined ivabradine and beta-blocker therapy in a patient with IST. The treatment optimized the HR response during exercise, suggesting that individualized strategies can enhance exercise performance in patients with IST and mild cardiomyopathy, despite the expected limitations of these medications.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/ehjcr\/ytae671","type":"journal-article","created":{"date-parts":[[2024,12,18]],"date-time":"2024-12-18T07:04:31Z","timestamp":1734505471000},"source":"Crossref","is-referenced-by-count":0,"title":["Paradoxical improvement in exercise tolerance and peak VO2 consumption after treatment with ivabradine and beta-blockers in a patient with mild dilated cardiomyopathy and inappropriate sinus tachycardia\u2014a case report"],"prefix":"10.1093","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0174-846X","authenticated-orcid":false,"given":"Francesca","family":"Graziano","sequence":"first","affiliation":[{"name":"Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova , Via Giustiniani 2, 35128 Padova ,","place":["Italy"]},{"name":"Department of Sports Medicine, Semmelweis University , Ga\u00e1l J\u00f3zsef \u00fat 9, 1122 Budapest ,","place":["Hungary"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matteo","family":"Pizzolato","sequence":"additional","affiliation":[{"name":"Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova , Via Giustiniani 2, 35128 Padova ,","place":["Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sergei","family":"Bondarev","sequence":"additional","affiliation":[{"name":"Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova , Via Giustiniani 2, 35128 Padova ,","place":["Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1487-0392","authenticated-orcid":false,"given":"Domenico","family":"Corrado","sequence":"additional","affiliation":[{"name":"Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova , Via Giustiniani 2, 35128 Padova ,","place":["Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3578-0583","authenticated-orcid":false,"given":"Alessandro","family":"Zorzi","sequence":"additional","affiliation":[{"name":"Department of Cardiac, Thoracic and Vascular Sciences and Public Health, University of Padova , Via Giustiniani 2, 35128 Padova ,","place":["Italy"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2024,12,18]]},"reference":[{"key":"2025012113095880500_ytae671-B1","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1016\/j.ccl.2023.03.003","article-title":"Left bundle branch block: characterization, definitions, and recent insights into conduction system physiology","volume":"41","author":"Pujol-L\u00f3pez","year":"2023","journal-title":"Cardiol Clin"},{"key":"2025012113095880500_ytae671-B2","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1016\/j.jelectrocard.2015.03.015","article-title":"Electrocardiographic right and left bundle branch block patterns in athletes: prevalence, pathology, and clinical significance","volume":"48","author":"Kim","year":"2015","journal-title":"J Electrocardiol"},{"key":"2025012113095880500_ytae671-B3","doi-asserted-by":"crossref","first-page":"882","DOI":"10.1111\/pace.14001","article-title":"Criteria for interpretation of the athlete's ECG: a critical appraisal","volume":"43","author":"Zorzi","year":"2020","journal-title":"Pacing Clin Electrophysiol"},{"key":"2025012113095880500_ytae671-B4","doi-asserted-by":"crossref","first-page":"2300","DOI":"10.1093\/eurheartj\/ehi580","article-title":"Bundle-branch block in middle-aged men: risk of complications and death over 28 years. 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