May 7th, 2013

Longer Detection Time Helps Prevent Unnecessary ICD Shocks

Increasing the detection intervals in ICD programming can reduce the number of unnecessary or inappropriate shocks, according to results of the ADVANCE III study published in JAMA.

A group of Italian investigators randomized 1,902 patients receiving an ICD to programming with either long- or standard-detection intervals. After 12 months of followup, patients in the long-detection group had a significant reduction in the primary endpoint, which was the total number of antitachycardia pacing (ATP) episodes and shocks:

  •      346 events versus 557 events, for an incident rate ratio of 0.63 (CI 0.51-0.78; p<0.001)
  •      ATP: 308 versus 142, IRR 0.58 (CI 0.47-0.72)
  •      Shock: 249 versus 154, IRR 0.77 (CI 0.59-1.01)

Although there was a significant reduction in the incidence of inappropriate shocks (IRR 0.55, CI 0.36-0.850), there was no difference in appropriate shocks (IRR 0.95, CI 0.67-1.37). There were no significant differences in mortality or episodes of syncope. Patients in the long-detection group were hospitalized less frequently.

The authors wrote that “ADVANCE III demonstrated that the use of a long detection setting… significantly reduced the rate of ventricular therapies delivered and inappropriate shocks compared with the standard detection setting.” They concluded that “this programming strategy may be a useful approach for ICD recipients.”

In an accompanying editorial, Merritt Raitt writes about the striking finding in previous trials in which ICD shocks have been associated with an increased risk of death. Although ADVANCE III was not designed to assess mortality, the benefits of long-detection programming are evident:

Regardless of whether these programming interventions lead to reduced mortality, the unequivocal reduction in ICD shocks and the reduction in hospitalization without an increase in adverse events such as syncope suggests that this programming approach should be considered for adoption in the care of patients with ICDs and clinical characteristics similar to those enrolled in these studies.”

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