title: Cardiac characteristics and long-term outcome in Andersen-Tawil syndrome patients related to KCNJ2 mutation.
abstract: OBJECTIVE
  Andersen-Tawil syndrome (ATS) is an uncommon form of channelopathy linked to mutations in the KCNJ2 gene. Currently, little is known about the long-term arrhythmic prognosis of this disease.
  
  
  RESULTS
  We conducted a retrospective multicentre study in nine French hospitals. Patients were recruited only if they were KCNJ2 mutation carriers. Thirty-six patients (female n = 22, 61%) from 20 unrelated kindred were included with a mean follow-up of 9.5 ± 8.2 years. We found 12 distinct KCNJ2 mutations in the 20 probands. Three of them were novel. Thirteen patients (36%) experienced syncope and one patient was resuscitated from cardiac arrest before diagnosis. The mean QTc interval was 439 ± 57 ms and QUc was 642 ± 64 ms. All patients had normal ejection fraction. Holter recordings in 33 patients found 11 272 premature ventricular complexes (PVCs) per day on average, 25 patients had episodes of bigeminy, and 25 patients had polymorphic PVCs. Twenty-three patients (70%) had non-sustained polymorphic ventricular tachycardia (VT), and six sustained polymorphic VT. Only one patient presented with torsades de pointes. Patients were treated with beta-blocker (n = 20), beta-blocker and amiodarone (n = 2), beta-blocker and flecainide (n = 6), or acetazolamide (n = 6). Radiofrequency ablation was attempted in five patients without clinical success. An implantable cardiac defibrillator was implanted in three patients. During follow-up, none of the patients died, four patients experienced syncope under treatment, and one patient had non-fatal cardiac arrest.
  
  
  CONCLUSIONS
  Despite a severe clinical presentation with a very high rate of ventricular arrhythmias, the arrhythmic prognosis of the ATS patients is relatively good under treatment.
authors.affiliation: L'Institut du Thorax, Department of Cardiology, Bd Monod, Nantes University Hospital, 44093, Nantes, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Delannoy
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sacher
authors.forename: Philippe
authors.initials: P
authors.lastname: Maury
authors.forename: Philippe
authors.initials: P
authors.lastname: Mabo
authors.forename: Jacques
authors.initials: J
authors.lastname: Mansourati
authors.forename: Isabelle
authors.initials: I
authors.lastname: Magnin
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Camous
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tournant
authors.forename: Eric
authors.initials: E
authors.lastname: Rendu
authors.forename: Florence
authors.initials: F
authors.lastname: Kyndt
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bézieau
authors.forename: Béatrice
authors.initials: B
authors.lastname: Guyomarch
authors.forename: Hervé
authors.initials: H
authors.lastname: Le Marec
authors.forename: Véronique
authors.initials: V
authors.lastname: Fressart
authors.forename: Isabelle
authors.initials: I
authors.lastname: Denjoy
authors.forename: Vincent
authors.initials: V
authors.lastname: Probst
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D050030:Andersen Syndrome / Q000150:complications / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004562:Electrocardiography; D005260:Female; D005602:France; D020022:Genetic Predisposition to Disease; D006323:Heart Arrest / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics*; D011379:Prognosis; D012189:Retrospective Studies; D013575:Syncope / Q000235:genetics; D013997:Time Factors; D055815:Young Adult
chemical_list: C489457:KCNJ2 protein, human; D024661:Potassium Channels, Inwardly Rectifying
keywords: Andersen–Tawil; Follow-up; Prognosis; Ventricular arrhythmias