title: Syncope in patients with an implantable cardioverter-defibrillator: incidence, prediction and implications for driving restrictions.
abstract: OBJECTIVE
  This retrospective study was undertaken to provide information on occurrence, risk prediction and prevention of syncope in patients with an implantable cardioverter-defibrillator (ICD).
  
  
  BACKGROUND
  ICDs effectively terminate ventricular tachycardia and fibrillation (VT/VF). Incapacitating symptoms, such as syncope, may still occur.
  
  
  METHODS
  We performed a retrospective analysis of data from 421 patients (clinical history, outpatient chart reviews and episode data) with mean (+/-SD) follow-up of 26 +/- 18 months.
  
  
  RESULTS
  Of 421 patients, 229 (54.4%) had recurrent VT/VF, and 62 (14.7%) had syncope. The actuarial survival rate free of VT/VF was 58%, 45% and 37% and that for survival free of syncope was 90%, 85% and 81% at 12, 24 and 36 months after implantation, respectively. Once VT/VF had occurred, 76%, 68% and 62% of patients remained free of syncope during the following 12, 24 and 36 months, and 68%, 64% and 56% remained free of second syncope 12, 24 and 36 months after first syncope, respectively. In cases of syncope, the mean cycle length (CL) of VT was 251 +/- 56 ms. A low baseline left ventricular ejection fraction (LVEF), induction of fast VT (CL <300 ms) during programmed ventricular stimulation and chronic atrial fibrillation (AF) were associated with an increased risk of syncope. If the LVEF was >40%, fast VT had not been induced, and patients had no chronic AF; 96%, 92% and 92% of patients remained free of syncope after 12, 24 and 36 months, respectively. Once patients had a VT recurrence, syncope during the first VT and a high VT rate were the strongest risk predictors of future syncope.
  
  
  CONCLUSIONS
  Identification of patients with an ICD with a low and high risk of syncope seems to be feasible and might help as a guide to driving restrictions in such patients.
authors.affiliation: Department of Cardiology/Angiology and Institute for Research in Arteriosclerosis, Westfälische Wilhelms-University, Münster, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Bänsch
authors.forename: J
authors.initials: J
authors.lastname: Brunn
authors.forename: M
authors.initials: M
authors.lastname: Castrucci
authors.forename: M
authors.initials: M
authors.lastname: Weber
authors.forename: F
authors.initials: F
authors.lastname: Gietzen
authors.forename: M
authors.initials: M
authors.lastname: Borggrefe
authors.forename: G
authors.initials: G
authors.lastname: Breithardt
authors.forename: M
authors.initials: M
authors.lastname: Block
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001334:Automobile Driving; D015986:Confounding Factors, Epidemiologic; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009790:Occupations; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013575:Syncope / Q000209:etiology*; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000188:drug therapy / Q000628:therapy; D014693:Ventricular Fibrillation / Q000150:complications* / Q000188:drug therapy / Q000628:therapy
chemical_list: D000889:Anti-Arrhythmia Agents