NEW YORK (Reuters Health) – The transvenous high-voltage leads of Medtronic’s Sprint Fidelis implantable cardioverter-defibrillator continue to deteriorate more rapidly than the earlier Medtronic Quattro Secure ICD leads, investigators report in Circulation for February 1, available online January 17.

“Our findings have significant implications for the management of patients who have Fidelis leads,” write Robert G. Hauser, of the Minneapolis Heart Institute Foundation, Minnesota, and colleagues.

The manufacturer withdrew Fidelis leads from the market in 2007 after a high fracture rate was seen, but about 100,000 patients still have the leads in place, the authors explain. Their current study examines the longevity of Fidelis leads compared Quattro leads and factors associated with failure.

At the authors’ three centers, 1023 Fidelis leads and 1668 Quattro leads were implanted in patients over an 8 year period up to January 2009.

“The failure rate for Fidelis leads was 2.81%/y compared with 0.43%/y for Quattro leads (p<0.0001),” the investigators found, and the 4-year survival rate was 87.0% for the Fidelis leads compared with 98.7% for Quattro leads (p<0.0001). None of the failures caused death or injury, but lead fractures led to inappropriate shocks in 42% of instances, according to the report. On multivariate analysis, factors associated with Fidelis lead failure were younger patient age, female gender, and cardiac disease, Dr. Hauser and colleagues note. This indicates that lead failure is related to physical activity and better ventricular systolic function, Dr. Avi Fischer of Mount Sinai Medical Center, New York, points out in a related editorial. “This should be considered as patients with Fidelis leads approach elective generator replacement,” he advises, “and in the design of new electrodes for use in patients whose cardiac disease permits a high level of physical activity despite their need for protection against potentially lethal ventricular tachyarrhythmias.” Circulation. 2011;123:358-354.