A March 2007 "Dear Doctor" Letter About Sprint Fidelis Heart Leads / Defibrillator Wires Was Little Noticed At The Time

And That Letter About What They Knew Back Then About Fractures And Malfunctions Is Hard To Find After Medtronic Announces FDA Recall In October 2007

On October 15, 2007 we posted an article on our Drug Injury Watch blog that was sub-titled "Events Leading Up To October 2007 FDA Recall Include A Little Noticed March 2007 'Dear Doctor' Letter And July 2007 Medical Journal Article About Model 6949".

Therein we set forth some information about this medical journal article, "Early failure of a small-diameter high-voltage implantable cardioverter-defibrillator lead", which was taken from the Abstract for this article published by Heart Rhythm.

About the little noticed March 2007 "Dear Doctor" letter from Medtronic about its Sprint Fidelis lead wire, we observed that this letter was hard to find at the time of the October 2007 FDA recall. In fact, as of October 17, 2007, despite our various efforts, we still cannot find this March 2007 to doctors on Medtronics web site nor the FDA's site. (Please let us know if you find it or have a copy of the letter.)

In an attempt to "re-create" that March 2007 letter about the Sprint Fidelis heart lead problem we extract this text from the October 15, 2007 "Dear Doctor" letter from Medtronic:

As we reported in March 2007, there are two primary locations1 where chronic conductor fractures have occurred on Sprint Fidelis leads: 1) the distal portion of the lead, affecting the anode (ring electrode) and 2) near the anchoring sleeve tie-down, predominantly affecting the cathode (helix tip electrode), and occasionally the high voltage conductor. High voltage conductor fractures could result in the inability to deliver defibrillation therapy. Anode or cathode conductor fractures (at either location) may present clinically as increased impedance, oversensing, increased interval counts, multiple inappropriate shocks, and/or loss of pacing output.

Approximately 90% of these fractures have occurred in the anode or cathode conductors, while 10% have occurred in the high voltage conductors.

Based on current information, we have identified five patient deaths in which a Sprint Fidelis lead fracture may have been a possible or likely contributing factor. We have confirmed 665 chronic fractures in returned leads.

The October 2007 letter, issued by Medtronic in conjunction with the Sprint Fidelis recall, was seemingly intended to update doctors about "[Medtronic's] current understanding of Sprint Fidelis' performance" but in doing so the company relied mostly on internal data and analysis, namely:

...six months additional Returned Product Analysis (RPA) and Medtronic System Longevity Study (SLS) data. In addition, we have performed extensive analysis using the Medtronic CareLink® Network...

Nowhere in Medtronic's October 2007 to doctors, however, is there any information about the increasing number of adverse events reports concerning Sprint Fidelis leads fracturing and causing injury which had been made to the FDA in the first ten months of 2007. Read more about the Medtronic recall on our Sprint Fidelis Lead Information Page >>