Problems with the Medtronic Fidelis Defibrillator Leads

Most implantable defibrillator units contain two leads, thus the preferred type of lead is the small diameter high-voltage lead, which is easier to insert and possibly remove. However, HV lead model, the Medtronic Sprint Fidelis has been pulled due off the market since the leads could fracture. For patients with the device, which is implanted near the shoulder and connected to the body with leads, according to Medtronic, removing the leads can cause more complications than the fracture itself would cause. Medtronic believes that out of 1000 patients with the affected leads, 9 of them will have leads fracture, with half of them given more than two days’ notice and the other half less than two days notice or no notice at all. A study at the Minneapolis heart institute had six of 583 patients experience lead failure. The fractures would cause unnecessary shocks or cause the unit not to function at all. Two options, plus removal, are available to patients. One option is to monitor the device for signs of fracture. Medtronic is developing new software for the pacemakers that would give three days notice before the unit fails. Another option is to surgically implant a replacement lead while capping the Fidelis lead. However, according to a study, monitoring did not detect nor prevent the failure of the device in 2/3 of the patients. In Minneapolis, none of the patients had complications from neither lead extrication nor removal.
Sources:
Linda M. Kallinen, Robert G. Hauser, Ken W. Lee, Adrian K. Almquist, William T. Katsiyiannis, Chuen Y. Tang, Daniel P. Melby, Charles C. Gornick, Failure of impedance monitoring to prevent adverse clinical events caused by fracture of a recalled high-voltage implantable cardioverter-defibrillator lead, Heart RhythmVolume 5, Issue 6, , June 2008, Pages 775-779.
(http://www.sciencedirect.com/science/article/B7GW9-4S01WMP-D/1/6a9881ae45ab62e7574e77bc9ed83b22)
Keywords: Implantable cardioverter-defibrillator; Lead; Complications; Follow-up

Robert G. Hauser, Linda M. Kallinen, Adrian K. Almquist, Charles C. Gornick, William T. Katsiyiannis, Early failure of a small-diameter high-voltage implantable cardioverter-defibrillator lead, Heart RhythmVolume 4, Issue 7, , July 2007, Pages 892-896.
(http://www.sciencedirect.com/science/article/B7GW9-4NFXDKJ-3/1/a5783e4201e37af697bd3654c5626c86)
Keywords: Implantable cardioverter-defibrillator; Lead; Complications; Failure

http://www.fda.gov/consumer/updates/medtronic101507.html

http://wwwp.medtronic.com/Newsroom/NewsReleaseDetails.do?itemId=1192213397218?=en_US

http://www.medtronic.com/fidelis/physician-letter-may-2008.html