Progressive decrease in amplitude of intracardiac ventricular electrogram and higher left ventricular ejection fraction are associated with conductors' externalization in Riata leads.

AIMS: Increased rates of structural abnormalities including externalized conductors have been reported in the Riata family of implantable cardioverter-defibrillator leads (St Jude Medical). Little is known about their reliability and the time lag for emergence of functional or structural abnormalities.

METHODS AND RESULTS: Thirty-six patients who received small-caliber leads of the Riata family and who completed face-profile flouroscopies, repeated at every 6 months were included. We assessed the prevalence of conductors' externalization and its relation to abnormal electrical parameters or adverse events. Thirty-six patients, mean age = 64 ± 10 years, with at least 7-month completed fluoroscopy follow-up were included in the analysis. Externalized conductors were identified in 12 (33%) patients after a 53-month (13-114) mean delay. A higher left ventricular ejection fraction (LVEF): 47 ± 13 vs. 33 ± 12%, P = 0.04, and a progressive decrease (≥30% of the initial value) in amplitude of ventricular electrogram 9/12 (75%) vs. 4/24 (17%), P = 0.03 were independently associated with the fluoroscopic failures. Detection of the conductors' externalization was preceded by an electrical lead abnormality in 10 (83%) patients.

CONCLUSION: Repeated face-profile fluoroscopies allowed detection of conductors' externalization in 33% of patients implanted with Riata leads. Better LVEF and a progressive decrease in amplitude of intracardiac ventricular electrogram were independently associated with externalized conductors. The structural abnormality was preceded by an electrical lead dysfunction 83% of patients.