{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T04:04:41Z","timestamp":1783051481469,"version":"3.54.6"},"reference-count":36,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"12","license":[{"start":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T00:00:00Z","timestamp":1764547200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circ: Arrhythmia and Electrophysiology"],"published-print":{"date-parts":[[2025,12]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND:<\/jats:title>\n                    <jats:p>Long QT syndrome (LQTS) is primarily an inherited condition associated with the risk of sudden cardiac death. Due to variable phenotypic expression, a prolonged QT interval on a 12-lead ECG is not always present. LQTS may present in the fetus with persistent bradycardia, including sinus bradycardia or functional 2:1 atrioventricular block. We report our experience of persistent fetal bradycardia prompting parental assessment for congenital LQTS.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS:<\/jats:title>\n                    <jats:p>From January 1, 2018 to November 1, 2023, 20 parents (20 mothers; 20 fathers) of fetuses presenting with persistent bradycardia and suspected congenital LQTS were assessed. Autoimmune-mediated atrioventricular block, diagnosed in the presence of maternal anti-Ro\/anti-La antibodies, and fetuses with ventricular tachycardia were excluded. Parental ECGs were acquired in the remainder, with comprehensive evaluation, including genomic testing, performed in 12 mothers and 11 fathers.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS:<\/jats:title>\n                    <jats:p>\n                      Among 20 fetuses, 16 had sinus bradycardia and 4 had 2:1 atrioventricular block (intermittent=2; persistent=2). Pathogenic LQTS genetic variants were found in 11 fetuses (\n                      <jats:italic toggle=\"yes\">KCNQ1<\/jats:italic>\n                      =8;\n                      <jats:italic toggle=\"yes\">KCNE1<\/jats:italic>\n                      =1;\n                      <jats:italic toggle=\"yes\">KCNH2<\/jats:italic>\n                      =1;\n                      <jats:italic toggle=\"yes\">CALM2<\/jats:italic>\n                      [calmodulin 2]=1), 9 mothers (\n                      <jats:italic toggle=\"yes\">KCNQ1<\/jats:italic>\n                      =7;\n                      <jats:italic toggle=\"yes\">KCNE1<\/jats:italic>\n                      =1;\n                      <jats:italic toggle=\"yes\">KCNH2<\/jats:italic>\n                      =1) and 1 father (\n                      <jats:italic toggle=\"yes\">KCNQ1<\/jats:italic>\n                      =1). Maternal corrected QT interval was higher in those with pathogenic variants compared with those who did not undergo genomic testing (456.9\u00b111.6 versus 425.9\u00b128.7 ms,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      =0.009) but &lt;400 ms in the paternal carrier. After review, 5 mothers with pathogenic variants were commenced on \u03b2-blockers (prepartum=4; postpartum=1). Provocation testing with a treadmill exercise test led to the initiation of \u03b2-blockade postnatally in one further case.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS:<\/jats:title>\n                    <jats:p>The first indication of parental LQTS may be persistent fetal bradycardia. This should prompt consideration of this diagnosis even with a normal maternal corrected QT interval and lead to the initiation of specific management strategies for pregnancy, delivery, and the postpartum period before the results of genomic testing are available.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1161\/circep.124.013360","type":"journal-article","created":{"date-parts":[[2025,12,2]],"date-time":"2025-12-02T10:00:11Z","timestamp":1764669611000},"update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":2,"title":["Fetal Bradycardia Prompting the Diagnosis and Management of Parental Long QT Syndrome"],"prefix":"10.1161","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0332-904X","authenticated-orcid":true,"given":"Kiruthika","family":"Ananthan","sequence":"first","affiliation":[{"name":"Department of Cardiology, St Thomas\u2019 Hospital, London, United Kingdom (K.A., R.B., J.W.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sian","family":"Chivers","sequence":"additional","affiliation":[{"name":"Department of Congenital Heart Disease, Evelina London Children\u2019s Hospital, United Kingdom (S.C., W.R., T.V., E.R., V.Z., J.M.S.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Will","family":"Regan","sequence":"additional","affiliation":[{"name":"Department of Congenital Heart Disease, Evelina London Children\u2019s Hospital, United Kingdom (S.C., W.R., T.V., E.R., V.Z., J.M.S.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9095-5887","authenticated-orcid":true,"given":"Antonio","family":"de Marvao","sequence":"additional","affiliation":[{"name":"Department of Women and Children\u2019s Health, King\u2019s College London, United Kingdom (A.d.M.)."},{"name":"British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine and Sciences, London, United Kingdom (A.d.M.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4084-4203","authenticated-orcid":true,"given":"Trisha","family":"Vigneswaran","sequence":"additional","affiliation":[{"name":"Department of Congenital Heart Disease, Evelina London Children\u2019s Hospital, United Kingdom (S.C., W.R., T.V., E.R., V.Z., J.M.S.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3030-9749","authenticated-orcid":true,"given":"Eric","family":"Rosenthal","sequence":"additional","affiliation":[{"name":"Department of Congenital Heart Disease, Evelina London Children\u2019s Hospital, United Kingdom (S.C., W.R., T.V., E.R., V.Z., J.M.S.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7505-6621","authenticated-orcid":true,"given":"Vita","family":"Zidere","sequence":"additional","affiliation":[{"name":"Department of Congenital Heart Disease, Evelina London Children\u2019s Hospital, United Kingdom (S.C., W.R., T.V., E.R., V.Z., J.M.S.)."},{"name":"School of Biomedical Engineering and Imaging Sciences, King\u2019s College London, United Kingdom (V.Z., J.W.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9981-9678","authenticated-orcid":true,"given":"Tessa","family":"Homfray","sequence":"additional","affiliation":[{"name":"Department of Medical Genetics, Royal Brompton Hospital, London, United Kingdom (T.H.)."},{"name":"Department of Medical Genetics, St George\u2019s University of London, United Kingdom (T.H.)."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6226-7611","authenticated-orcid":true,"given":"Catherine","family":"Williamson","sequence":"additional","affiliation":[{"name":"Institute of Reproductive and Developmental Biology, Imperial College London, United Kingdom 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