RESUMO
AIMS: The long-term performance of Pellethane 80A (P80A) endocardial pacing leads has previously been called into question. We report our experience with an endocardial pacemaker lead with silicone outer and Pellethane 2363-90A (P90) inner insulator. METHODS: Between November 1993 and March 1998, 129 P90A and 189 non-P90A ventricular leads were implanted. Lead malfunction was defined as > or = 25%) deviation in lead impedance or a two-fold reduction in sensing threshold during follow-up. Sensing and capture thresholds and lead impedance were assessed intraoperatively, immediately postoperatively, at 24 h and 6-12 weeks following implant and semiannually thereafter. Adequacy of lead positioning and lead-header interface were documented radiographically in each case. RESULTS: During 204 patient years of follow-up, 10/129 (8%) Oscor RX P90A leads malfunctioned. Average time to malfunction was 14 +/- 11 months. During 166 patient years of follow-up, none of the 189 non-P90A ventricular leads met criteria for malfunction (P < 0.05). There was no difference in patient age, sex, and arrhythmia indication between groups. Sensing problems were overcome with pacemaker reprogramming. CONCLUSION: We conclude that Oscor RX passive fixation ventricular leads with external silicone and inner P90A insulation exhibit an 8%, insulation malfunction rate within 14 +/- 11 months of implant. This is significantly higher than non-P90A leads implanted with identical technique and follow-up regimen. More frequent follow up may be warranted in patients with P90A containing leads.
