Defibrillation threshold testing fails to show clinical benefit during long-term follow-up of XXXX undergoing cardiac resynchronization therapy defibrillator implantation.

@entity1 @entity712 @entity591 @entity737 @entity299 @entity204
BACKGROUND: The utility of defibrillation threshold testing in @entity1 undergoing @entity737 ( @entity737 ) implantation is controversial. Higher defibrillation thresholds have been noted in @entity1 undergoing implantation of @entity299 ( @entity299 ). Since the risks and potential benefits of testing may be higher in this population, we sought to assess the impact of defibrillation safety margin or vulnerability safety margin testing in @entity299 recipients. METHODS AND RESULTS: A total of 256 consecutive subjects who underwent @entity299 implantation between January 2003 and December 2007 were retrospectively reviewed. Subjects were divided into two groups based on whether (n= 204) or not (n= 52) safety margin testing was performed. @entity1 characteristics, @entity591 therapies, procedural results, and clinical outcomes were recorded. Baseline characteristics, including @entity712 ( @entity712 ) severity, were comparable between the groups. Four cases of @entity712 exacerbation (2%), including one leading to one @entity204 , were recorded in the tested group immediately post-implantation. No complications were observed in the untested group. After a mean follow-up of 32    20 months, the proportion of appropriate shocks in the two groups was similar (31 vs. 25%, P = 0.49). There were three cases of failed appropriate shocks in the tested group, despite adequate safety margins at implantation, whereas no failed shocks were noted in the untested group. Survival was similar in the two groups. CONCLUSION: Defibrillation efficacy testing during implant of @entity299 was associated with increased morbidity and did not predict the success of future device therapy or improve survival during long-term follow-up.
