DO STEROID-ELUTING ELECTRODES REALLY HAVE BETTER PERFORMANCE THAN OTHER STATE-OF-THE-ART DESIGNS

A multicenter study evaluated the performance of atrial and ventricula r unipolar leads with porous steroid-eluting and platinized grooved el ectrodes. A total of 563 leads were implanted in 451 patients. These i ncluded 311 ventricular and 97 atrial steroid-eluting electrodes; and 112 ventricular and 43 atrial leads with platinized electrodes. Mean f ollow-up was greater-than-or-equal-to 1 year. At implant there were no significant differences in threshold parameters in either chamber. Ch ronically, however, the steroid-eluting lead consistently had signific antly lower pacing thresholds in both chambers. For example, after 360 days implant, steroid-eluting electrodes had 0.23 +/- 0.10 msec ventr icular thresholds at 0.8 V compared to 0.45 +/- 0.3 msec in the platin ized group (P < 0.0001). In the atrium, the steroid-eluting lead's 6-m onth thresholds at 0.8 V were 0.15 +/- 0.06 msec compared to 0.9 +/- 0 .8 msec for the platinized electrode (P < 0.01). The chronic ventricul ar QRS amplitudes were significantly greater for the steroid-eluting e lectrode (P < 0.0005). There were no significant differences in atrial sensing and no incidence of atrial undersensing in the study. The low and consistent thresholds of the steroid-eluting electrodes would hav e permitted pacing in the ventricle at less-than-or-equal-to 2.5 V wit hout compromising safety factor in 99.4% of the patients. The other 0. 6% required 5 V temporarily. In the atrium, 100% of the patients could have been paced safely at reduced output. In spite of this, 63% of th e implanters lacked the confidence to use reduced outputs.