Failure of a spliced DF-4 ICD lead

Abstract

A 52-year-old man with Brugada syndrome underwent single-chamber implantable cardioveter-defibrillator (ICD) implantation (Medtronic Sprint Quattro 6947M, Medtronic, Inc, Minneapolis, MN) by using a dual-coil DF-4 ICD lead. He did not engage in any high-risk sports or activities that would predispose him to lead fracture. The ICD generator was implanted subpectorally. No sharp angulation of the lead in the pocket was noted on the postoperative chest X-ray. Seventeen months post-implantation, remote monitoring reported a “red” alert related to a high impedance (43000 Ω) of the right ventricular pace/sense lead and many short R-R interval detections. Lead Integrity Alert was activated, which prevented inappropriate ICD therapies. An urgent clinic visit was arranged and threshold testing showed failure of right ventricular capture even at maximal pacing output. Manipulation of the pocket reproduced oversensing in true bipolar, but not in integrated bipolar sensing. Lead extraction was achieved with manual traction 2 days later. Although the polyurethane insulation surrounding the lead was intact, a conductor fracture could be observed through the insulation just distal to the DF-4 connector (Figure 1). Char inside the insulation at the fracture site was also noted. The postmarketing quality service assessment confirmed that the pace/sense ring conductor was fractured 6 cm from the connector end without insulation breach. This first report of a DF-4 ICD lead fracture highlights its potential early vulnerability. Medtronic Sprint Quattro DF-4 lead has been entirely redesigned, with 3 different splices located in the lead. This may increase the risk of connector failure. Although no conclusions can be drawn from this single report, the risks and benefits of this new connector should be considered carefully before adopting it as a new standard of care. Previous studies of ICD lead failure (involving recall and non-recall leads) have not demonstrated any association between technical or radiographic factors and subsequent lead fracture. 1,2 Although this new