title: Recollection of pain due to inappropriate versus appropriate implantable cardioverter-defibrillator shocks.
abstract: BACKGROUND
  Although inappropriate shocks are known to be an important consequence of implantable cardioverter-defibrillators (ICDs), the subjective experience of pain intensity perceived by those receiving inappropriate versus appropriate shocks has not previously been examined.
  
  
  METHODS
  One hundred ICD patients underwent a standardized interview by an investigator blinded to the clinical history. Patients with a previous ICD shock were asked to describe the intensity of the associated pain on a standard 0-10 scale (10 being the worst pain they had ever experienced). Medical charts were then examined for any history of inappropriate and/or appropriate ICD discharges.
  
  
  RESULTS
  Thirty-five of the 100 patients had a record of at least one ICD shock, and 17 had experienced at least one inappropriate shock. Those with a history of an inappropriate shock described a significantly higher median pain scale (9, interquartile range [IQR] 8-10) compared to those with a history of only appropriate shocks (median 4, IQR 2-8, P = 0.0011). In multivariable analysis, a history of an inappropriate shock was the only predictor statistically significantly associated with an increase in shock pain: the pain scale for those with inappropriate shocks was higher by 2.8 points on average after multivariable adjustment (95% confidence interval 0.29-5, P = 0.030). Eighteen patients had considered having their device deactivated, and a history of an inappropriate shock was the only factor independently associated with this consideration.
  
  
  CONCLUSIONS
  Compared to those who have received only appropriate shocks, inappropriate ICD shocks are associated with a recollection of greater pain and consideration of device inactivation.
authors.affiliation: Cardiac Electrophysiology Section, University of California, San Francisco, California, USA. marcusg@medicine.ucsf.edu
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Marcus
authors.forename: Derrick W
authors.initials: DW
authors.lastname: Chan
authors.forename: Rita F
authors.initials: RF
authors.lastname: Redberg
mesh_terms: D002140:California / Q000453:epidemiology; D015897:Comorbidity; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004556:Electric Injuries / Q000453:epidemiology*; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors