Very Late Follow‐Up of a Passive Defibrillator Lead Under Recall: Do Failure Rates Increase during Long‐Term Observation

Background The Medtronic Sprint Fidelis lead (SFL; Medtronic Inc., Minneapolis, MN, USA) has a significantly impaired long‐term survival, and active fixation leads fare worse than passive leads. The goal of this study was to present data of a series of passive SFL only with very long mean follow‐up of more than 6 years. Methods Patients in whom a passive SFL was implanted in two large Swiss centers were followed. We excluded eight (5.5%) patients with a follow‐up of <6 months. Patients who died or were lost during follow‐up were censored at death or last device check, all others on January 31, 2014. We employed two different definitions of failure: strict = fracture with inappropriate discharge; sudden increase in impedance >1,500 or high‐voltage impedance >100 Ohm; >300 nonphysiological short interventricular‐intervals. Lenient = any of the above plus a linear increase in impedance >1,500 Ohm or a linear decrease in sensing to a level that treating cardiologists considered inappropriate. Results We included 137 patients. Age was 60 ± 12 years. Mean and median follow‐up were 6.2 ± 2.1 and 6.8 (interquartile range 4.8–7.8) years. Applying the strict definition, 12 leads (8.8%) were replaced after 4.9 ± 2.4 years (range 1.2–8.1). Applying the lenient definition, 14 leads (10.2%) failed. Cumulative lead survival was 98.5% at 3, 96.9% at 4, 94.2% at 5, and 93.1% at 6 years. Leads “at risk” were: n = 122 (89%), 115 (84%), 101 (74%), and 88 (64%). Conclusions In this population with passive SFLs, 5‐year lead survival is impaired with 94.2% based on 74% of leads “at risk” at this time point.