Riata lead failure with normal electrical lead parameters and normal fluoroscopic appearance.

Recently, insulation breach of the Riata lead raised a big concern. Management of these externalized leads has been addressed by professional organizations. However, what to do in patients with Riata leads without manifested failure is an ongoing clinical dilemma. Here, we present two clinical scenarios where the implantable cardioverter defibrillator system failed to deliver shock therapy in spite of having a new ICD generator and "appropriately functioning leads" as revealed by lead interrogation.