Insulation defects in riata implantable cardioverter-defibrillator leads

Abstract

Background The structures composing implantable cardioverter-defibrillator (ICD) leads have become more complicated and thinner with technological advances. Silicon insulation defects with and without clinically manifested electrical abnormalities have been reported in Riata leads (St. Jude Medical). Objective The aim of this study was to assess the incidence and clinical implications of insulation defects in Riata leads implanted at our hospital. Methods The subjects included 10 consecutive patients who received 8-French Riata ICD leads with dual-coil conductors (model 1580 or 1581) between 2006 and 2010 at our hospital. Operative records, chest X-rays and interrogation data were reviewed. Results In all cases, Atlas+ (St. Jude Medical) was used as an ICD generator and the Riata leads were im-planted transvenously and fixed to the right ventricular apex. During a mean follow-up period of 52±9 (36-70) months, chest X-rays revealed insulation defects in Riata leads and conductor wires projecting from the bodies of the Riata leads in two of 10 (20%) patients. One of the patients received inappropriate ICD thera-pies due to T-wave oversensing based on attenuation of R waves and augmentation of T waves 41 months af-ter implantation. In the other patient, an insulation defect without any clinically manifested electrical troubles was detected 50 months after implantation. Conclusion Riata leads have a high incidence of insulation defects, which may be occasionally accompa-nied by inappropriate ICD discharges. For patients with Riata leads, careful observation of any changes in the lead-electrical measurements and a routine chest X-ray follow-up are necessary. © 2012 The Japanese Society of Internal Medicine.