title: Implantable cardioverter-defibrillators have reduced the incidence of resuscitation for out-of-hospital cardiac arrest caused by lethal arrhythmias.
abstract: BACKGROUND
  Over the last decades, a gradual decrease in ventricular fibrillation (VF) as initial recorded rhythm during resuscitation for out-of-hospital cardiac arrest (OHCA) has been noted. We sought to establish the contribution of implantable cardioverter-defibrillator (ICD) therapy to this decline.
  
  
  RESULTS
  Using a prospective database of all OHCA resuscitation in the province North Holland in the Netherlands (Amsterdam Resuscitation Studies [ARREST]), we collected data on all patients in whom resuscitation for OHCA was attempted in 2005-2008. VF OHCA incidence (per 100 000 inhabitants per year) was compared with VF OHCA incidence data during 1995-1997, collected in a similar way. We also collected ICD interrogations of all ICD patients from North Holland and identified all appropriate ICD shocks in 2005-2008; we calculated the number of prevented VF OHCA episodes, considering that only part of the appropriate shocks would result in avoided resuscitation. VF OHCA incidence decreased from 21.1/100 000 in 1995-1997 to 17.4/100 000 in 2005-2008 (P<0.001). Non-VF OHCA increased from 12.2/100 000 to 19.4/100 000 (P<0.001). VF as presenting rhythm declined from 63% to 47%. In 2005-2008, 1972 ICD patients received 977 shocks. Of these shocks, 339 were caused by a life-threatening arrhythmia. We estimate that these 339 shocks have prevented 81 (minimum, 39; maximum, 152) cases of VF OHCA, corresponding with 33% (minimum, 16%; maximum, 63%) of the observed decline in VF OHCA incidence.
  
  
  CONCLUSIONS
  The incidence of VF OHCA decreased over the last 10 years in North Holland. ICD therapy explained a decrease of 1.2/100 000 inhabitants per year, corresponding with 33% of the observed decline in VF OHCA.
authors.affiliation: Department of Cardiology, Room G4-229, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: Hulleman
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Berdowski
authors.forename: Joris R
authors.initials: JR
authors.lastname: de Groot
authors.forename: Pascal F H M
authors.initials: PF
authors.lastname: van Dessel
authors.forename: C Jan Willem
authors.initials: CJ
authors.lastname: Borleffs
authors.forename: Marieke T
authors.initials: MT
authors.lastname: Blom
authors.forename: Abdenasser
authors.initials: A
authors.lastname: Bardai
authors.forename: Carel C
authors.initials: CC
authors.lastname: de Cock
authors.forename: Hanno L
authors.initials: HL
authors.lastname: Tan
authors.forename: Jan G P
authors.initials: JG
authors.lastname: Tijssen
authors.forename: Rudolph W
authors.initials: RW
authors.lastname: Koster
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000401:mortality / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D058687:Out-of-Hospital Cardiac Arrest / Q000517:prevention & control*; D012151:Resuscitation / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000453:epidemiology / Q000517:prevention & control