title: Interference detection in implantable defibrillators induced by therapeutic radiation therapy.
abstract: BACKGROUND
  Electromagnetic fields and ionising radiation during radiotherapy can influence the functioning of ICDs. Guidelines for radiotherapy treatment were published in 1994, but only based on experience with pacemakers. Data on the influence of radiotherapy on ICDs is limited.
  
  
  OBJECTIVE
  We determined the risk to ICDs of interference detection induced by radiotherapy.
  
  
  METHODS
  In our study we irradiated 11 ICDs. The irradiation was performed with a 6 megavolt photon beam. In each individual device test, a total of 20 Gray was delivered in a fractionated fashion. During each irradiation the output stimulation rate was monitored and electrogram storage was activated. In case of interference the test was repeated with the ICD outside and the lead(s) inside and outside the irradiation field.
  
  
  RESULTS
  With the ICD inside the irradiation field, interference detection was observed in all ICDs. This caused pacing inhibition or rapid ventricular pacing. Ventricular tachycardia (VT) or ventricular fibrillation (VF) detection occurred, which would have caused tachycardia-terminating therapy. If the ICD was placed outside the irradiation field, no interference was observed.
  
  
  CONCLUSIONS
  Interference by ionising radiation on the ICDs is demonstrated both on bradycardia and tachycardia therapy. This can have consequences for patients. Recommendations for radiotherapy are presented in this article.
authors.forename: G J
authors.initials: GJ
authors.lastname: Uiterwaal
authors.forename: B G F
authors.initials: BG
authors.lastname: Springorum
authors.forename: E
authors.initials: E
authors.lastname: Scheepers
authors.forename: G S
authors.initials: GS
authors.lastname: de Ruiter
authors.forename: C W
authors.initials: CW
authors.lastname: Hurkmans
keywords: ICD; interference detection; radiotherapy