{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T10:11:56Z","timestamp":1759831916370,"version":"build-2065373602"},"reference-count":22,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T00:00:00Z","timestamp":1759795200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Egypt Heart J"],"abstract":"<jats:title>Abstract<\/jats:title>\n          <jats:sec>\n            <jats:title>Background<\/jats:title>\n            <jats:p>Brugada syndrome is a rare, inherited cardiac disorder that predisposes individuals to life-threatening ventricular arrhythmias, often leading to sudden cardiac arrest. In many cases, the characteristic electrocardiographic (ECG) findings of Brugada syndrome are not present at baseline but can be unmasked using sodium channel blockers. While intravenous ajmaline is the preferred agent, its limited availability has led to the increased use of oral flecainide for provocation testing. Previous studies have used 300\u2013400\u00a0mg doses, but the efficacy and safety of a lower dose, such as 200\u00a0mg, have not been systematically evaluated. This report presents three cases demonstrating that a 200\u00a0mg oral flecainide dose may be sufficient to unmask the diagnostic Type 1 Brugada ECG pattern in selected patients.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Case presentation<\/jats:title>\n            <jats:p>Three male patients (aged 44, 48, and 60\u00a0years) with suspected Brugada syndrome based on Type 2 ECG patterns underwent flecainide challenge testing. One patient received a 400\u00a0mg oral dose, while the other two received 200\u00a0mg doses. ECG changes were monitored continuously for 24\u00a0h. All three patients developed coved-type ST-segment elevation in the right precordial leads (Type 1 Brugada ECG pattern), confirming the diagnosis. The time to onset of diagnostic ECG changes ranged from 15 to 60\u00a0min, with peak changes occurring between 90\u00a0min and 5\u00a0h. No patients experienced syncope, ventricular arrhythmias, or conduction disturbances during or after testing.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusions<\/jats:title>\n            <jats:p>This case series suggests that a 200\u00a0mg oral flecainide challenge can effectively and safely unmask the diagnostic Type 1 Brugada ECG pattern in selected patients. However, given the small sample size and absence of serum drug concentration data, caution is warranted in interpreting these findings. A lower dose may be a practical alternative to the conventional 400\u00a0mg, maintaining diagnostic sensitivity while potentially reducing adverse event risk. Further prospective studies with larger cohorts and longer follow-up are essential to validate the diagnostic performance, safety, and clinical implications of low-dose oral flecainide provocation testing.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1186\/s43044-025-00679-3","type":"journal-article","created":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T09:51:00Z","timestamp":1759830660000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Low-dose oral flecainide provocation test for Brugada syndrome: a case series"],"prefix":"10.1186","volume":"77","author":[{"given":"Xuan","family":"Nguyen Thanh","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tuan","family":"Ngoc Tran","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thuan","family":"Nguyen Van","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nguyen","family":"Nguyen Duc","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thao","family":"Pham Ngoc","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hanh","family":"Nguyen Thi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hoi","family":"Nguyen Van","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luyen","family":"Nguyen Van","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2025,10,7]]},"reference":[{"issue":"6","key":"679_CR1","doi-asserted-by":"publisher","first-page":"1391","DOI":"10.1016\/0735-1097(92)90253-J","volume":"20","author":"P Brugada","year":"1992","unstructured":"Brugada P, Brugada J (1992) Right bundle branch block, persistent ST-segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndrome: A multicenter report. 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All study procedures were conducted in accordance with the Declaration of Helsinki and relevant guidelines and regulations. Written informed consent to participate was obtained from all participants before enrollment in the study.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Written informed consent for publication of anonymized data and accompanying images (such as electrocardiogram tracings) was obtained from all participants. Written informed consent for publication was obtained from each patient included in this case series. Each patient consented to the publication of their anonymized personal details and any associated images (such as electrocardiogram tracings). All identifying information has been removed to protect patient privacy.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for Publication"}},{"value":"The authors declare no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing Interests"}}],"article-number":"91"}}