Insulation damage in a shock wire: an unexpected fluoroscopic image.

We report on a patient with a single-chamber implantable cardioverter defibrillator admitted with an increase in high-voltage lead impedance, detected with home-monitoring, and inappropriate shocks due to noise on the electrogram. Chest x-ray revealed no abnormalities. Fluoroscopy before the revision procedure showed insulation failure with migration of the shock wire in the heart. The lead was removed and replaced with a new shock lead. This is, as far as we know, the first report on such a particular insulation failure, detected with home-monitoring and inappropriate shocks.