Abstract 14362: Progressive Decrease in Amplitude of Intracardiac Ventricular Electrogram in Riata Leads May Precede Conductors' Externalization Detected by Repeated Face-Profile Fluoroscopies
Increased rates of structural defects including externalized conductors have been reported in the Riata family of implantable cardioverter-defibrillator (ICD) leads (St Jude Medical, Sylmar, CA). The reliability of defibrillation leads with abraded cables that are not immediate cause of failure is unknown. Little is known about the time lag for emergence of functional or structural abnormalities in such leads.
Methods: Forty-eight patients who received small-caliber leads of the Riata family in our institution between 2002 and 2008 were called for an additional visit including face-profile thoracic fluoroscopy followed by repeated fluoroscopies at every six-month visits. We assessed the prevalence of insulation defects with externalized cables and their relation with abnormal electrical parameters detected by regular ICD interrogations. We evaluated the time lag for emergence of electrical or structural dysfunction of the leads.
Results: Thirty-six patients, mean age=64±10 years, with at least 7-months completed fluoroscopy follow-up were included in analysis. After 57±30 months mean follow-up, 72% of patients completed 2-6 spaced fluoroscopies. Externalized conductors were identified in 8(22%) patients after a 53-months (13-114) mean delay and in 4 (11%) cases the images were classified as borderline. Progressive decrease (>30%) in amplitude of ventricular electrogram was associated with the structural abnormalities: 9/12 (75%) vs 4/24 (17%), p = 0.001. There were no differences according the changes in the stimulation threshold : 4/12 (33%) vs 4/24 (17%), p = 0.26, or the lead impedance: 5/12 (23%) vs 4/24 (17%), p = 0.1. Detection of insulation damage was preceded by an electrical abnormality in 10 (83%) patients including 4 patients who experienced inappropriate shocks.The mean time lag between electrical and structural abnormalities was 48 months (1-90).
Conclusion: Repeated face-profile fluoroscopies allowed detection of insulation damage with externalized conductors in 22% of patients implanted with Riata leads. The structural abnormality was preceded by an electrical lead dysfunction in 83% of patients. Progressive decrease in amplitude of ventricular electrogram was independently associated with insulation defects.
- © 2012 by American Heart Association, Inc.