title: Mid-Term Follow-up of School-Aged Children With Borderline Long QT Interval.
abstract: There are no definitive diagnostic criteria or follow-up strategies for long QT syndrome (LQTS) in children with a borderline long QT interval (b-LQT).
  
  
  
  We retrospectively evaluated the clinical course, genetic testing results, corrected QT interval (QTc), and LQTS score of 59 school-aged children (5-18 years old) with a b-LQT (400≤QTc<500 ms). Syncope, but neither aborted cardiac arrest nor sudden cardiac death, occurred in 2 patients during the follow-up (6±3.4 years) with LQTS scores ≥4.5 points. The genetic testing results were positive in 92%, 57%, and 67% of patients with high, intermediate, and low probabilities of LQTS, respectively. The maximum and mean QTc during the follow-up significantly differed among the categories with a probability of LQTS, but not the minimum QTc. However, the QTc at rest and at the recovery point after exercise stress testing dramatically changed at the last follow-up. Consequently, the probability of LQTS changed in half of the patients.
  
  
  
  The LQTS score is a reasonable indicator for evaluating school-aged children with a b-LQT, and patients with a low LQTS score appear to be at low risk for cardiac events. However, the LQTS score can change during follow-up. Therefore, when there is doubt or concern for patients with a b-LQT, it is preferable to continue following them. Guidelines on follow-up strategies are desired for b-LQT.
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Aya
authors.initials: A
authors.lastname: Miyazaki
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Heima
authors.initials: H
authors.lastname: Sakaguchi
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Yu
authors.initials: Y
authors.lastname: Matsumura
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Hayama
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Kanae
authors.initials: K
authors.lastname: Noritake
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Jun
authors.initials: J
authors.lastname: Negishi
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Tsuda
authors.affiliation: Department of Preventive Cardiology, National Cerebral and Cardiovascular Center.|Department of Preventive Medicine and Epidemiologic Informatics, National Cerebral and Cardiovascular Center.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Miyamoto
authors.affiliation: Department of Cardiovascular Medicine, Division of Arrhythmias and Electrophysiology, National Cerebral and Cardiovascular Center.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aiba
authors.affiliation: Department of Cardiovascular Medicine, Division of Arrhythmias and Electrophysiology, National Cerebral and Cardiovascular Center.|Department of Cardiovascular Medicine, Graduate School of Medicine, Nippon Medical School.
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
authors.affiliation: Department of Cardiovascular Medicine, Division of Arrhythmias and Electrophysiology, National Cerebral and Cardiovascular Center.
authors.forename: Kengo
authors.initials: K
authors.lastname: Kusano
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Isao
authors.initials: I
authors.lastname: Shiraishi
authors.affiliation: Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohuchi
mesh_terms: D002318:Cardiovascular Diseases / Q000209:etiology; D002648:Child; D005500:Follow-Up Studies; D006801:Humans; D008133:Long QT Syndrome / Q000235:genetics*; D012189:Retrospective Studies; D013575:Syncope / Q000209:etiology
keywords: Borderline long QT interval; LQTS score; Long QT syndrome; Mid-term follow-up; Schoolchildren