The Impact of Inappropriate Implantable Cardiac Defibrillator Shocks on Cardiovascular Morbidity and Mortality.

Background: The impact of inappropriate implantable cardiac defibrillator (ICD) shocks on cardiac outcomes is controversial. Shocks due to lead noise are unique in that they are not an outcome of worsening rhythm status. In this study, we compared the outcome of patients with and without inappropriate shocks who underwent Sprint Fidelis lead (Medtronic Inc., Minneapolis, MN, USA) extraction.

Methods: We retrospectively identified 147 patients who underwent Sprint Fidelis lead extraction in our institution between May 2007 and August 2012. The patients were separated into those with (Group 1) and without (Group 2) inappropriate shocks due to lead noise. Pertinent data were obtained from chart review.

Results: There were 57 and 90 patients in Groups 1 and 2, respectively. The mean ± standard deviation number of inappropriate shocks in Group 1 was 16 ± 22. There was no difference in the baseline demographics, risk factors, and cardiac history between the groups. There were no extraction-related deaths and there was no difference in the rate of periprocedural complications between the groups. The mean total hospital length of stay (LOS) was longer for Group 1 versus 2; however, the mean postprocedure LOS was the same between the groups. During follow-up, there was no difference in the cardiac readmission rate over a 1-year period (four vs seven patients in Group 1 vs 2, respectively; P = 0.8). Long-term follow-up revealed similar mortality rates in both groups. (18 patients in Group 1, and 21 patients in Group 2; P = 0.8).

Conclusions: Inappropriate shocks due to lead noise do not seem to predispose to a worse clinical outcome after ICD lead extraction.