{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,9]],"date-time":"2026-11-09T17:17:46Z","timestamp":1794244666760,"version":"4.9.0"},"reference-count":27,"publisher":"Royal College of Psychiatrists","issue":"6","license":[{"start":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T00:00:00Z","timestamp":1623283200000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["cambridge.org"],"crossmark-restriction":true},"short-container-title":["Br J Psychiatry"],"published-print":{"date-parts":[[2021,12]]},"abstract":"<jats:sec id=\"S0007125021000581_sec_a1\"><jats:title>Background<\/jats:title><jats:p>Clozapine is associated with increased risk of myocarditis. However, many common side-effects of clozapine overlap with the clinical manifestations of myocarditis. As a result, there is uncertainty about which signs, symptoms and investigations are important in distinguishing myocarditis from benign adverse effects of clozapine. Clarity on this issue is important, since missing a diagnosis of myocarditis or discontinuing clozapine unnecessarily may both have devastating consequences.<\/jats:p><\/jats:sec><jats:sec id=\"S0007125021000581_sec_a2\"><jats:title>Aims<\/jats:title><jats:p>To examine the clinical characteristics of clozapine-induced myocarditis and to identify which signs and symptoms distinguish true myocarditis from other clozapine adverse effects.<\/jats:p><\/jats:sec><jats:sec id=\"S0007125021000581_sec_a3\" sec-type=\"methods\"><jats:title>Method<\/jats:title><jats:p>A retrospective analysis of the record database for 247 621 patients was performed. A natural language processing algorithm identified the instances of patients in which myocarditis was suspected. The anonymised case notes for the patients of each suspected instance were then manually examined, and those whose instances were ambiguous were referred for an independent assessment by up to three cardiologists. Patients with suspected instances were classified as having confirmed myocarditis, myocarditis ruled out or undetermined.<\/jats:p><\/jats:sec><jats:sec id=\"S0007125021000581_sec_a4\" sec-type=\"results\"><jats:title>Results<\/jats:title><jats:p>Of 254 instances in 228 patients with suspected myocarditis, 11.4% (<jats:italic>n<\/jats:italic> = 29 instances) were confirmed as probable myocarditis. Troponin and C-reactive protein (CRP) had excellent diagnostic value (area under the curve 0.975 and 0.896, respectively), whereas tachycardia was of little diagnostic value. All confirmed instances occurred within 42 days of clozapine initiation.<\/jats:p><\/jats:sec><jats:sec id=\"S0007125021000581_sec_a5\" sec-type=\"conclusions\"><jats:title>Conclusions<\/jats:title><jats:p>Suspicion of myocarditis can lead to unnecessary discontinuation of clozapine. The \u2018critical period\u2019 for myocarditis emergence is the first 6 weeks, and clinical signs including tachycardia are of low specificity. Elevated CRP and troponin are the best markers for the need for further evaluation.<\/jats:p><\/jats:sec>","DOI":"10.1192\/bjp.2021.58","type":"journal-article","created":{"date-parts":[[2021,6,10]],"date-time":"2021-06-10T07:36:08Z","timestamp":1623310568000},"page":"644-651","update-policy":"https:\/\/doi.org\/10.1017\/policypage","source":"Crossref","is-referenced-by-count":43,"title":["Clozapine-induced myocarditis: electronic health register analysis of incidence, timing, clinical markers and diagnostic accuracy"],"prefix":"10.1192","volume":"219","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9550-3895","authenticated-orcid":false,"given":"Aviv","family":"Segev","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9477-9745","authenticated-orcid":false,"given":"Ehtesham","family":"Iqbal","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Theresa 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\u00a9 The Author(s), 2021. Published by Cambridge University Press on behalf of the Royal College of Psychiatrists","name":"copyright","label":"Copyright","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http:\/\/creativecommons.org\/licenses\/by\/4.0\/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.","name":"license","label":"License","group":{"name":"copyright_and_licensing","label":"Copyright and Licensing"}},{"value":"This content has been made available to all.","name":"free","label":"Free to read"}]}}