title: A randomized comparison of a bipolar steroid-eluting electrode and a bipolar microporous platinum electrode: implications for long-term programming.
abstract: Differences in acute and chronic pacing thresholds were compared in patients receiving either the Medtronic Model 4004 steroid-eluting lead or the Medtronic Model 4012 microporous platinum lead. Patients (n = 35) were randomized at the time of implant to receive either a steroid-eluting (n = 17) or a microporous (n = 18) lead. Pacing thresholds were determined within 24 hours and at 2, 4, 6, 12, 24, and 52 weeks postimplant. By 2 weeks postimplant, pacing thresholds measured at 0.8, 1.6, 2.5, 3.3, and 4.2 V were significantly lower in the steroid lead group compared to the microporous lead group (P < 0.05). At 24 weeks, the voltage threshold at 0.3 msec was 0.8 V in 88% of patients with a steroid lead whereas this threshold was only observed in 33% of patients with the microporous lead (P < 0.01). At 52 weeks the pacing energy measured at 1.6 V, twice pulse duration threshold, was significantly lower in the steroid lead group (0.81 +/- 0.59 microJ) compared to the microporous lead group (1.25 +/- 0.60 microJ, P < 0.05). Thirteen patients in the steroid lead group and 9 patients in the microporous lead group have been programmed at a pulse amplitude of 1.6 V since the 24-week follow-up visit. These patients have been followed for a minimum of 6 months without documented failure to capture. This study shows that pacemaker/lead systems with stable chronic low thresholds can be safely programmed to low pulse amplitude settings. This practice will prolong the longevity of pulse generators.
authors.affiliation: Division of Cardiology, University of Calgary, Alberta, Canada.
authors.forename: A M
authors.initials: AM
authors.lastname: Gillis
authors.forename: J M
authors.initials: JM
authors.lastname: Rothschild
authors.forename: K
authors.initials: K
authors.lastname: Hillier
authors.forename: W
authors.initials: W
authors.lastname: Fudge
authors.forename: T M
authors.initials: TM
authors.lastname: Kieser
authors.forename: A
authors.initials: A
authors.lastname: Maitland
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000628:therapy; D003907:Dexamethasone / Q000008:administration & dosage*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D010984:Platinum; D016062:Porosity
chemical_list: D010984:Platinum; D003907:Dexamethasone