Active fixation leads--long-term threshold reduction using a drug-infused ceramic collar

Previous investigators, including our group, have reported the threshold reduction benefits of steroid-releasing leads. To date, all published literature has been for the passive fixation versions. The application of steroids should also enhance the performance of active fixation leads. We have developed and tested an atrial and a ventricular Accufix lead with a dexamethasone acetate-releasing, porous ceramic collar (DA DEC). A long-term sheep study has shown a significant reduction in thresholds (THR) when compared to standard Accufix leads without the collar (ACC) for atrial (ATR) and ventricular (VENT) versions (bipolar THR [0.5 msec] at 24 weeks: VENT DA DEC = 0.51 +/- 0.07, VENT ACC = 1.49 +/- 1.03; ATR DA DEC = 1.31 +/- 1.14, ATR ACC = 2.99 +/- 1.31). All other parameters tested, including pacing and sensing impedance as well as polarization overpotential, were similar for the two groups. The Accufix DEC leads therefore have excellent potential for low energy stimulation.