Riata ICD Lead Failures Increased at Steady Rate Over 10 Years

December 11, 2017

HALIFAX, NS — Six years following a high-profile class 1 recall, failure rates for Riata (St Jude Medical) implantable defibrillator leads reported by centers across Canada are 7.25% and 9.45% for 7 and 8 French leads, respectively, at least 10 years after implantation[1].

Those rates are an update of 5-year rates reported from the same survey in January 2013, which were 3.3% for the 7 French and 5.2% for the 8 French Riata leads, as reported at the time by theheart.org | Medscape Cardiology.

The leads were recalled after reports of electrical failures later found related at least partly to a quirk of their design. Riata conductor wires were eroding and then protruding through their silicone insulation, or "externalizing." That would sometimes cause electrical abnormalities and changes to impedance and thresholds and possibly high-voltage shorts, inappropriate shocks, and failure to defibrillate.

The 10-year update, reported December 1, 2017 in Heart Rhythm with lead author Dr Ratika Parkash (QEII Health Sciences Centre, Halifax, NS) and many of the same coauthors from the 5-year report, is based on 1352 remaining advisory Riata leads at 17 centers in the Canadian Registry of Electronic Device Outcomes registry. About 35% of the leads were 7 French and 65% were 8 French.

Suspected or confirmed electrical failures occurring in 35 cases consisted of right ventricular pacing impedance that was increased (28.6%) or decreased (5.7%), oversensing (40%), increased high-voltage impedance (8.6%), "compromised pacing" (8.6%), and failure to defibrillate (2.9%). There were no cases of high-voltage impedance with shocks or inappropriate shocks.

Reasons for the 110 system revisions included electrical or structural abnormalities (34.6% and 20%, respectively), infection (12.7%), device upgrades (10%), and normal battery depletion (36.4%).

The study was supported by Abbott Medical. Parkash discloses receiving research funding from St Jude Medical. Disclosures for the coauthors are listed in the report.

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