title: Clinical characteristics and genetic background of congenital long-QT syndrome diagnosed in fetal, neonatal, and infantile life: a nationwide questionnaire survey in Japan.
abstract: BACKGROUND
  Data on the clinical presentation and genotype-phenotype correlation of patients with congenital long-QT syndrome (LQTS) diagnosed at perinatal through infantile period are limited. A nationwide survey was conducted to characterize how LQTS detected during those periods is different from that in childhood or adolescence.
  
  
  RESULTS
  Using questionnaires, 58 cases were registered from 33 institutions. Diagnosis (or suspicion) of LQTS was made during fetal life (n=18), the neonatal period (n=31, 18 of them at 0 to 2 days of life), and beyond the neonatal period (n=9). Clinical presentation of LQTS included sinus bradycardia (n=37), ventricular tachycardia/torsades de pointes (n=27), atrioventricular block (n=23), family history of LQTS (n=21), sudden cardiac death/aborted cardiac arrest (n=14), convulsion (n=5), syncope (n=5), and others. Genetic testing was available in 41 (71%) cases, and the genotype was confirmed in 29 (71%) cases, consisting of LQT1 (n=11), LQT2 (n=11), LQT3 (n=6), and LQT8 (n=1). Ventricular tachycardia/torsades de pointes and atrioventricular block were almost exclusively observed in patients with LQT2, LQT3, and LQT8, as well as in those with no known mutation. In LQT1 patients, clues to diagnosis were mostly sinus bradycardia or family history of LQTS. Sudden cardiac death/aborted cardiac arrest (n=14) was noted in 4 cases with no known mutations as well as in 4 genotyped cases, although the remaining 6 did not undergo genotyping. Their subsequent clinical course after aborted cardiac arrest was favorable with administration of beta-blockers and mexiletine and with pacemaker implantation/implantable cardioverter-defibrillator.
  
  
  CONCLUSIONS
  Patients with LQTS who showed life-threatening arrhythmias at perinatal periods were mostly those with LQT2, LQT3, or no known mutations. Independent of the genotype, aggressive intervention resulted in effective suppression of arrhythmias, with only 7 deaths recorded.
authors.affiliation: Department of Child Health, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan. hhorigom@md.tsukuba.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Horigome
authors.forename: Masami
authors.initials: M
authors.lastname: Nagashima
authors.forename: Naokata
authors.initials: N
authors.lastname: Sumitomo
authors.forename: Masao
authors.initials: M
authors.lastname: Yoshinaga
authors.forename: Hiroya
authors.initials: H
authors.lastname: Ushinohama
authors.forename: Mari
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Junko
authors.initials: J
authors.lastname: Shiono
authors.forename: Koh
authors.initials: K
authors.lastname: Ichihashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Hiroko
authors.initials: H
authors.lastname: Goto
authors.forename: Kenji
authors.initials: K
authors.lastname: Waki
authors.forename: Masaki
authors.initials: M
authors.lastname: Arima
authors.forename: Hisashi
authors.initials: H
authors.lastname: Takasugi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tauchi
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ikoma
authors.forename: Noboru
authors.initials: N
authors.lastname: Inamura
authors.forename: Hideto
authors.initials: H
authors.lastname: Takahashi
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D003625:Data Collection; D016757:Death, Sudden, Cardiac / Q000209:etiology; D004562:Electrocardiography; D005260:Female; D005315:Fetal Diseases; D005838:Genotype; D006323:Heart Arrest / Q000209:etiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008133:Long QT Syndrome / Q000151:congenital* / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D008297:Male; D009154:Mutation; D010138:Pacemaker, Artificial; D010641:Phenotype; D011296:Prenatal Diagnosis
chemical_list: D000889:Anti-Arrhythmia Agents