title: Extended detection time to reduce shocks is safe in secondary prevention patients: The secondary prevention substudy of PainFree SST.
abstract: Prolonged ventricular fibrillation (VF) detection has been shown to reduce implantable cardioverter-defibrillator (ICD) therapies and improve prognosis in primary prevention ICD patients. Data in secondary prevention patients are limited.
  
  
  
  The PainFree SST secondary prevention study is the largest trial of secondary prevention patients randomized between standard and prolonged detection to assess the safety of this strategy in these patients.
  
  
  
  A total of 705 secondary prevention patients implanted with an ICD in the PainFree SST trial were enrolled in this substudy; 353 patients were randomized to VF detection of 18/24 intervals and 352 patients to 30/40. All other VF parameters were standardized by protocol.
  
  
  
  The 1-year arrhythmic syncope-free rates in the standard and prolonged groups were 97.7% vs 96.9%, respectively, (P = .0034 for noninferiority). Freedom from all-cause syncope was 96% in both arms (P = .0013 for noninferiority). There was no difference in the time to first appropriate or inappropriate VF therapy. However, the rates of treated VF episodes were lower in the prolonged arm (1.48 per patient per year vs 0.44 per patient per year, P = .0001). A trend toward lower mortality in the prolonged group was not statistically different (5.6% 1 year, 12% 2 years vs 3.8% 1 year, 7.7% 2 years, adjusted hazard ratio = 0.60, P = .061).
  
  
  
  This large prospective randomized study shows that prolonged detection can safely be programmed in secondary prevention ICD patients with new or existing devices. This programming strategy decreases the rate of treated events and is not associated with an increased risk of syncope or mortality.
authors.affiliation: Royal Jubilee Hospital, Victoria, Canada. Electronic address: LDSterns@gmail.com.
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Sterns
authors.affiliation: Cardiologie, University Medical Center, Utrecht, Netherlands.
authors.forename: Mathias
authors.initials: M
authors.lastname: Meine
authors.affiliation: Cardiology Division, Kinkl University, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kurita
authors.affiliation: Catharina Ziekenhuis, Eindhoven, Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Meijer
authors.affiliation: Fondazione Cardiocentro Ticino, Lugano, Switzerland.
authors.forename: Angelo
authors.initials: A
authors.lastname: Auricchio
authors.affiliation: Kokura Memorial Hospital, Kitakyushu, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ando
authors.affiliation: Penn-Presbyterian Medical Center, University of Pennsylvania Health Systems, Timonium, Maryland.
authors.forename: Charles T
authors.initials: CT
authors.lastname: Leng
authors.affiliation: Hirosaki University Graduate School of Medicine, Aomori, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
authors.affiliation: QE II Health Sciences Centre, Halifax, Canada.
authors.forename: John L
authors.initials: JL
authors.lastname: Sapp
authors.affiliation: Medtronic Inc, Minneapolis, Minnesota.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Brown
authors.affiliation: Medtronic Inc, Minneapolis, Minnesota.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Lexcen
authors.affiliation: Medtronic Bakken Research Center, Maastricht, Netherlands.
authors.forename: Bart
authors.initials: B
authors.lastname: Gerritse
authors.affiliation: The Christ Hospital/The Ohio Heart & Vascular Center, Cincinnati, Ohio.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Schloss
mesh_terms: D000368:Aged; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D017147:Defibrillators, Implantable / Q000009:adverse effects / Q000706:statistics & numerical data; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D010146:Pain / Q000209:etiology / Q000517:prevention & control; D011379:Prognosis; D055502:Secondary Prevention / Q000379:methods / Q000706:statistics & numerical data; D016019:Survival Analysis; D013575:Syncope / Q000209:etiology / Q000517:prevention & control; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy
keywords: Complications; Implantable defibrillator; Inappropriate shocks; Shock reduction algorithm; Ventricular fibrillation; Ventricular tachycardia