title: Long-term follow-up of patients with short QT syndrome.
abstract: OBJECTIVE
  The aim of this study was to investigate the clinical characteristics and the long-term course of a large cohort of patients with short QT syndrome (SQTS).
  
  
  BACKGROUND
  SQTS is a rare channelopathy characterized by an increased risk of sudden death. Data on the long-term outcome of SQTS patients are not available.
  
  
  METHODS
  Fifty-three patients from the European Short QT Registry (75% males; median age: 26 years) were followed up for 64 ± 27 months.
  
  
  RESULTS
  A familial or personal history of cardiac arrest was present in 89%. Sudden death was the clinical presentation in 32%. The average QTc was 314 ± 23 ms. A mutation in genes related to SQTS was found in 23% of the probands; most of them had a gain of function mutation in HERG (SQTS1). Twenty-four patients received an implantable cardioverter defibrillator, and 12 patients received long-term prophylaxis with hydroquinidine (HQ), which was effective in preventing the induction of ventricular arrhythmias. Patients with a HERG mutation had shorter QTc at baseline and a greater QTc prolongation after treatment with HQ. During follow-up, 2 already symptomatic patients received appropriate implantable cardioverter defibrillator shocks and 1 had syncope. Nonsustained polymorphic ventricular tachycardia was recorded in 3 patients. The event rate was 4.9% per year in the patients without antiarrhythmic therapy. No arrhythmic events occurred in patients receiving HQ.
  
  
  CONCLUSIONS
  SQTS carries a high risk of sudden death in all age groups. Symptomatic patients have a high risk of recurrent arrhythmic events. HQ is effective in preventing ventricular tachyarrhythmia induction and arrhythmic events during long-term follow-up.
authors.affiliation: Division of Cardiology, University of Turin, San Giovanni Battista Hospital, Turin, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Giustetto
authors.forename: Rainer
authors.initials: R
authors.lastname: Schimpf
authors.forename: Andrea
authors.initials: A
authors.lastname: Mazzanti
authors.forename: Chiara
authors.initials: C
authors.lastname: Scrocco
authors.forename: Philippe
authors.initials: P
authors.lastname: Maury
authors.forename: Olli
authors.initials: O
authors.lastname: Anttonen
authors.forename: Vincent
authors.initials: V
authors.lastname: Probst
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Blanc
authors.forename: Pascal
authors.initials: P
authors.lastname: Sbragia
authors.forename: Paola
authors.initials: P
authors.lastname: Dalmasso
authors.forename: Martin
authors.initials: M
authors.lastname: Borggrefe
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Gaita
mesh_terms: D000293:Adolescent; D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000628:therapy*; D015331:Cohort Studies; D003645:Death, Sudden; D017147:Defibrillators, Implantable; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography / Q000379:methods; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011802:Quinidine / Q000031:analogs & derivatives / Q000494:pharmacology; D013575:Syncope / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C014486:hydroquinidine; D011802:Quinidine