BACKGROUND: The natural history of insulation defects with inside-out conductor externalization in recalled St Jude Medical Riata defibrillator leads is not well understood. OBJECTIVE:S To determine the prevalence of externalization in a nationwide screening. Secondary aims were to examine time dependence and location of externalization, association with electrical failure, and fluoroscopic diagnostic performance. METHODS: All 299 patients with recalled Riata leads in Denmark were identified, and all except one underwent fluoroscopy and device interrogation. Externalizations were confirmed by multiple investigators. RESULTS: The prevalence of externalization was 32 of 298 (11%) at a mean dwell time of 5.1 years. The prevalence was 21 of 98 (21%) for 8-F leads and 11 of 200 (6%) for 7-F leads; however, 8-F leads had longer dwell times. The degree of externalization was correlated with dwell time (Spearman's ρ = .37; P = .03). External-ization more often included the lead segment below the tricuspid annulus in dual coil leads than in single coil leads (69% vs 16%; P = .004). No association was observed between externalization and electrical function. Fluoroscopic diagnostic performance was good with positive and negative predictive values of 88% and 99%, respectively. CONCLUSIONS: The prevalence of externalization in a nationwide screening is at the same level as reported in previous studies with similar lead dwell times. The degree of externalization is time dependent, and location seems to differ between single and dual coil leads. Long-term lead performance and association with electrical failure need further clarification. Fluoroscopy has a good diagnostic performance in clinical practice.

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Heart Rhythm
Department of Cardiology

Larsen, J.M, Riahi, S, Nielsen, J.C, Videbaek, R, Haarbo, J, Due, K.M, … Johansen, J.B. (2013). Nationwide fluoroscopic screening of recalled riata defibrillator leads in Denmark. Heart Rhythm, 10(6), 821–827. doi:10.1016/j.hrthm.2013.02.010