title: QTc prolongation in patients with hearing loss: Electrocardiographic and genetic study.
abstract: BACKGROUND
  The aim of the study was to determine, whether electrocardiogram (ECG) screening could reduce the risk of sudden cardiac death in patients with hearing loss through the early diagnosis of Jervell and Lange-Nielsen syndrome and the introduction of the therapy.
  
  
  METHODS
  One thousand and eighty patients with hearing loss (aged 21.8 ± 19.9 years) underwent ECG. Additionally, all subjects were asked to complete a 3-question survey. Those who met, at least, one of the high-risk criteria underwent further cardiac assessment and genetic testing.
  
  
  RESULTS
  QTc assessment was possible in 1,027 patients. Mean QTc measured 422.8 ± 23.7 ms in 313 women, 414.9 ± 27.7 ms in 273 men and 421.1 ± 21.5 ms in 441 children (individuals younger than 14 years). Abnormal QTc was found in 13 (4.1%) women, 20 (7.3%) men, and 72 (16.3%) children. In the studied group, no recessive mutation of KNCQ1 or KCNE1 was found. In 6 patients, other mutations were found: in KCNQ1 (n = 1), in KCNH2 (n = 3) and in SCN5A (n = 1), which were pathogenic for long-QT-syndromes (LQTS), and 2 mutations of unknown clinical significance in SCN5A. Overall, out of these 6 patients LQTS was diagnosed in 3 asymptomatic patients, but with abnormal QTc and in 2 patients with normal QTc, but who were previously treated for epilepsy.
  
  
  CONCLUSIONS
  Jervell and Lange-Nielsen syndrome is a very rare condition even in a population with hearing loss. In this population, the prevalence of prolonged QT interval is increased over the general population. Further investigations are necessary.
authors.affiliation: Department and Clinic of Cardiac Rehabilitation and Noninvasive Electrocardiology, Institute of Cardiology, Warsaw, Poland. agasa@mp.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Sanecka
authors.forename: Elżbieta Katarzyna
authors.initials: EK
authors.lastname: Biernacka
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Szperl
authors.forename: Magdalena
authors.initials: M
authors.lastname: Sosna
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Mueller-Malesińska
authors.forename: Urszula
authors.initials: U
authors.lastname: Kozicka
authors.forename: Rafał
authors.initials: R
authors.lastname: Baranowski
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kosiec
authors.forename: Hubert
authors.initials: H
authors.lastname: Łazarczyk
authors.forename: Henryk
authors.initials: H
authors.lastname: Skarżyński
authors.forename: Piotr
authors.initials: P
authors.lastname: Hoffman
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bieganowska
authors.forename: Ryszard
authors.initials: R
authors.lastname: Piotrowicz
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D005260:Female; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D006320:Hearing Tests; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D007223:Infant; D029593:Jervell-Lange Nielsen Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D011044:Poland; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D005819:Genetic Markers
keywords: Jervell and Lange-Nielsen syndrome; electrocardiogram; hearing loss; long-QT syndrome