Clinical and genetic spectrum of neonatal arrhythmia in a NICU

Dai, Yi; Yin, Rong; Yang, Lin; Li, Zhihua

doi:10.21037/tp-21-233

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…Newborns with inherited arrhythmias have a higher risk of congenital heart disease or heart failure [ 6 ]. When a patient presents with intrauterine manifestations of fetal AVB and ventricular tachycardia, congenital LQTS should be highly suspected, and its strong correlation with the clinical course of malignancy should be specially evaluated [ 7 ].…”

Section: Discussionmentioning

confidence: 99%

A rare case with fetal autoimmune heart block and KNCH2 variant–induced long QT syndrome: a controversial opinion on prenatal management strategy

Xie

et al. 2023

BMC Cardiovasc Disord

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Background Among all fetal heart block patients, > 50% cases are associated with maternal autoimmune diseases, and such patients should receive treatment. However, nearly half of fetal heart block cases involve a mother with negative results following autoimmune antibody screening. A few studies have reported long QT syndrome (LQTS) can also present as a severe fetal bradycardia, which does not respond to fetal treatment. Herein, we reported a rare case of an infant who presented with high-degree autoimmune-mediated fetal atrioventricular block (AVB) with LQTS induced by a novel KCNH2 variant. This case led us to review our prenatal therapeutic strategy. Case presentation A 1-year-old boy presented to our heart center having experienced syncope 5 times in the past year. He had previously presented with fetal bradycardia during the fetal stage from 27 + 3 gestational weeks. The fetal echocardiography demonstrated AVB (2:1 transmission). As the maternal autoimmune antibody results were positive, his mother had received dexamethasone treatment during pregnancy; subsequently, the fetal AVB had changed from 2:1 to 4:3 transmission with elevated ventricular beating rates. However, this patient was identified to have complete AVB after birth. The initial electrocardiogram and Holter measurements at hospital administration showed complete AVB, pleomorphic ventricular tachycardia, a prolonged QT interval (QT = 602 ms, corrected QT = 538 ms), and wide and deep inverted T-waves. Meanwhile, torsades de pointes could be observed in several transit ventricular tachycardias based on Holter monitoring review. Genetic testing revealed KCNH2 c.2483G > A variant–induced LQTS. An implantable cardioverter defibrillator device and permanent pacemaker were both considered as therapeutic alternations; his parents ultimately accepted the implantation of a permanent pacemaker. Conclusions For fetuses with autoimmune-mediated AVB, intrauterine treatment should still be pursued immediately. However, once the treatment outcomes are deemed unacceptable or unexpected, other genetic variant–related channelopathies should be highly suspected. If the fetus lacks a positive family history, fetal genetic testing should be recommended to improve the prognosis of such patients by introducing integrative therapeutic strategies between the prenatal and postnatal phases.

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Section: Discussionmentioning

confidence: 99%

A rare case with fetal autoimmune heart block and KNCH2 variant–induced long QT syndrome: a controversial opinion on prenatal management strategy

Xie

et al. 2023

BMC Cardiovasc Disord

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“…Inherit arrhythmias lead to higher risks of heart dysfunction, even SCD, in early childhood ( Dai et al, 2021 ). However, most types of inherit arrhythmias have not been identified in fetuses, which indicates a low intrauterine penetrance.…”

Section: Discussionmentioning

confidence: 99%

“…The loss of function variants in KCNH2 are the leading cause of LQTS ( Liao et al, 2021 ). Three encoding ion channel genes have been identified as responsible for most of the LQTS cases: KCNQ1 (Kv7.1 channel) causing LQT1 ( Adler et al, 2020 ), KCNH2 (Kv11.1 channel) causing LQT2 ( Martínez-Barrios et al, 2022 ), and SCN5A (Nav1.5 channel) causing LQTS ( Dai et al, 2021 ). Thus, the early and timely ability to distinguish congenital LQTS and autoimmune-associated fetal heart block is critical to avoid unnecessary long-term prenatal DEX exposure.…”

Section: Introductionmentioning

confidence: 99%

Case Report: A novel KNCH2 variant-induced fetal heart block and the advantages of fetal genomic sequencing in prenatal long-term dexamethasone exposure

Huang

Jing

et al. 2022

Front. Genet.

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Background: Fetal bradycardia is a common but severe condition. In addition to autoimmune-mediated fetal heart block, several types of channelopathies induce high-degree atrioventricular block (AVB). Long QT syndrome (LQTS) is a major cause of non-autoimmune-mediated fetal heart block. Due to the limitations of prenatal diagnostic technologies, LQTS is seldom identified unless fetal genetic screening is performed. Thus, long-term prenatal dexamethasone (DEX) exposure can become a challenge for these patients. We report on a rare case of a novel KCNH2 variant related to LQTS and associated with high-degree fetal AVB with long-term DEX exposure. This case led us to review our prenatal administration strategy for such patients.Case Presentation: A fetus was identified with high-degree AVB (2:1 transduction at 28 + 2 gestational weeks). Typical tests of immune function in the pregnant woman were conducted including tests for thyroid function, rheumatic screening, autoimmune antibodies (such as anti-Ro/SSA and anti-La/SSB), and anti-nuclear antibodies (anti-ANA). Following the recommended protocol, the pregnant patient received DEX (0.75 mg/day) during pregnancy. Subsequently, the fetal AVB changed from 2:1 to prolonged AV intervals with ventricular tachycardia, which suggested a therapeutic benefit of DEX in some respects. However, a high-degree AVB with a significantly prolonged QTc interval was identified in the neonate following birth. Genetic testing revealed that a KCNH2 c.1868C>A variant induced LQTS. The body length remained approximately -3.2 SD from the reference value after prenatal long-term DEX exposure, which indicated a developmental restriction. Additionally, the functional validation experiments were performed to demonstrate the prolonged duration of calcium transit both in depolarization and repolarization with the KCNH2 c.1868C>A variant.Conclusion: Genetic screening should be recommended in fetuses with autoimmune antibody negative high-degree AVB, especially for 2:1 transduction AVB and in fetuses with changes in fetal heart rhythm following initial DEX treatment. Genetic screening may help identify genetic variant–related channelopathies and avoid unexpected prenatal exposure of DEX and its possible long-term adverse postnatal complications.

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“…Newborns with genetic arrhythmias, including ventricular tachycardia (VT), fibrillation, Long QT Syndrome (LQTS), or high-grade atrioventricular (AV) block, might be at an increased risk for congenital heart malformations (CHDs) [ 27 ], which are the most commonly diagnosed genetic disorders in newborns. In Europe, the reported prevalence of CHDs at birth is 8.2 cases per 1000 live births [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Early Screening for Long QT Syndrome and Cardiac Anomalies in Infants: A Comprehensive Study

Nosetti,

Zaffanello,

Lombardi

et al. 2024

Clinics and Practice

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(1) Background: Sudden Infant Death Syndrome (SIDS) represents sudden and unexplained deaths during the sleep of infants under one year of age, despite thorough investigation. Screening for a prolonged QTc interval, a marker for Long QT Syndrome (LQTS), should be conducted on all newborns to reduce the incidence of SIDS. Neonatal electrocardiograms (ECGs) could identify congenital heart defects (CHDs) early, especially those not detected at birth. Infants with prolonged QTc intervals typically undergo genetic analysis for Long QT Syndrome. (2) Methods: The study involved infants aged 20–40 days, born with no apparent clinical signs of heart disease, with initial ECG screening. Infants with prenatal diagnoses or signs/symptoms of CHDs identified immediately after birth, as well as infants who had previously had an ECG or echocardiogram for other medical reasons, were excluded from the study. We used statistical software (SPSS version 22.0) to analyze the data. (3) Results: Of the 42,200 infants involved, 2245 were enrolled, with 39.9% being males. Following this initial screening, 164 children (37.8% males) with prolonged QTc intervals underwent further evaluation. Out of these 164 children, 27 children were confirmed to have LQTS. However, only 18 children were finally investigated for genetic mutations, and mutations were identified in 11 tests. The most common mutations were LQT1 (54.5%), LQT2 (36.4%), and LQT3 (1 patient). Treatment options included propranolol (39.8%), nadolol (22.2%), inderal (11.1%), metoprolol (11.1%), and no treatment (16.7%). The most common abnormalities were focal right bundle branch block (54.5%), left axis deviation (9.2%), and nonspecific ventricular repolarization abnormalities (7.1%). Multiple anomalies were found in 0.47% of children with focal right bundle branch block. Structural abnormalities were associated with specific features in 267 patients (11.9%), primarily isolated patent foramen ovale (PFO) at 61.4%. (4) Conclusions: This screening approach has demonstrated effectiveness in the early identification of LQTS and other cardiac rhythm anomalies, with additional identification of mutations and/or prolonged QTc intervals in family members. Identifying other ECG abnormalities and congenital heart malformations further enhances the benefits of the screening.

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Clinical and genetic spectrum of neonatal arrhythmia in a NICU

Cited by 5 publications

References 23 publications

A rare case with fetal autoimmune heart block and KNCH2 variant–induced long QT syndrome: a controversial opinion on prenatal management strategy

A rare case with fetal autoimmune heart block and KNCH2 variant–induced long QT syndrome: a controversial opinion on prenatal management strategy

Case Report: A novel KNCH2 variant-induced fetal heart block and the advantages of fetal genomic sequencing in prenatal long-term dexamethasone exposure

Early Screening for Long QT Syndrome and Cardiac Anomalies in Infants: A Comprehensive Study

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