Detailed electrical analysis of lead failures in a small-scaled right ventricular defibrillator lead: reality of Sprint Fidelis medical device recalls.
BACKGROUND
This paper illustrates our experience with the Sprint Fidelis lead (SF, single coil model 6931). We investigated lead failure incidence, analysed for possible predictive factors and examined the efficacy of integrated early ICD warning systems.


METHODS
We analysed 181 consecutive patients with SF (follow up: 406 +/- 250 days). Left ventricular ejection fraction, age, gender, follow up, ICD indication, type of device, duration of implantation, and target vein used for implantation were evaluated as potential predictive factors of lead failure. Additionally, the predictive value of recommended impedance alert adaptations, the potential effects of the sensing integrity counter (SIC), and of the new lead integrity alert (LIA)(R) were studied.


RESULTS
Nine lead failures were identified. Lead failure occurred significantly more often in patients with single- and dual-chamber devices. None of the patients under cardiac resynchronisation therapy (CRT) had a lead failure (p=0.04). Seven failures (78%) became apparent through inappropriate shock interventions. Impedance alert adaptations did not prevent any inappropriate shock intervention, but the SIC and the activation of the LIA might have prevented inappropriate interventions. A fractured pace/sense ring conductor was identified as the most vulnerable part of the SF lead (in 7 failures, 78%).


CONCLUSIONS
We verified an increased failure rate in patients with the SF lead. Only patients with CRT devices were free from lead failure, suggesting a correlation with increased physical activity. The impedance alert reprogramming did not predict any inadequate shock interventions but LIA may become a new valuable tool for the early detection of lead failure signs.
Kreuz
Jens
J
Department of Medicine-Cardiology, University of Bonn, Sigmund-Freud-Strasse 25, Bonn, Germany. jens.kreuz@ukb.uni-bonn.de
Balta
Osman
O
Zimmer
Sebastian
S
Fimmers
Rolf
R
Lickfett
Lars
L
Mellert
Fritz
F
Nickenig
Georg
G
Schwab
Joerg Otto
JO
D000368:Aged; D017147:Defibrillators, Implantable; D004560:Electricity; D004867:Equipment Design; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057053:Safety-Based Medical Device Withdrawals