Externalized conductors and insulation failure in Biotronik defibrillator leads: History repeating or a false alarm?

Abstract

Conductor externalization and insulation failure are frequent complications with the recalled St. Jude Medical Riata implantable cardioverter-defibrillator (ICD) leads. Conductor externalization is a “unique” failure mechanism: Cables externalize through the insulation (“inside-out” abrasion) and appear outside the lead body. Recently, single reports described a similar failure also for Biotronik leads. Moreover, some studies reported a high rate of electrical dysfunction (not only insulation failure) with Biotronik Linox leads and a reduced survival rate in comparison with the competitors. In this paper we describe the case of a patient with a Biotronik Kentrox ICD lead presenting with signs of insulation failure and conductor externalization at fluoroscopy. Due to the high risk of extraction we decided to implant a new lead, abandoning the damaged one; lead reimplant was uneventful. Subsequently, we review currently available literature about Biotronik Kentrox and Linox ICD lead failure and in particular externalized conductors. Some single-center studies and a non-prospective registry reported a survival rate between 88% and 91% at 5 years for Linox leads, significantly worse than that of other manufacturers. However, the preliminary results of two ongoing multicenter, prospective registries (GALAXY and CELESTIAL) showed 96% survival rate at 5 years after implant, well within industry standards. Ongoing data collection is needed to confirm longer-term performance of this family of ICD leads.

Analysis of early failure of Biotronik Linox Smart implantable cardioverter‐defibrillator leads: A comparative study of three defibrillator leads

“…Recently, isolated cases and single‐center and multicenter studies have reported that Biotronik Linox leads show high rates of electrical dysfunction and insulation failure of up to 12% at 5 years. The aim of this study was to compare the rate of lead failure in Linox Smart leads with that of two other leads: Endotak Reliance and Sprint Quattro Secure.…”

An unusually late dislodged atrial lead catching externalized ICD‐lead conductor. A rare cause of simultaneous atrial and ICD lead over‐sensing

“…[1][2][3] The conductor to the pace/sense ring electrode and the conductor coil to the RV defibrillation coil are located "decentered" in the lead isolation around the central conductor coil to the tip electrode. 4 Externalization of the shock coil could have led to short circuiting of current if interaction with the atrial lead had occurred and potentially low shock impedance and potentially ineffective shock. The attachment of the atrial lead tip helix likely contributed to electrical failure, through insulation damage, when the atrial lead was "snared" in the externalized conductor loop of the defibrillator lead.…”

Cardiac magnetic resonance imaging: Which information is useful for the arrhythmologist?

“…However, it is now well-known that ejection fraction alone has limited sensitivity and specificity as a risk marker for SCD, because it is not able to distinguish the risk of sudden death from death caused by heart failure or other non-cardiac diseases. Subsequently, many patients implanted for primary prevention according to current guidelines will have little benefit from their ICD, with a low rate of appropriate ICD therapy (2%-4%/year)[ 9 ], while they can suffer from side effects (even > 10%/year overall), in particular inappropriate shocks, lead failure and infections[ 10 , 11 ]. On the other side, many patients who are at risk of SCD are missed when using only LVEF, because the largest part of sudden arrhythmic death patients have only mildly depressed ejection fraction[ 9 , 12 , 13 ].…”