Updated: Jul 22, 2026

A Mouse Distraction Osteogenesis Model
Published on: November 14, 2018
N Anderson1, R Mathivanar, M Skalsky
1Telectronics Pacing Systems, Applied Research, New South Wales, Australia.
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This study tested a new type of pacing lead with a drug-infused ceramic collar to reduce energy needs. Researchers compared modified and standard leads in sheep models over 24 weeks. They found that the modified leads had significantly lower thresholds, meaning less energy is needed for pacing. Other parameters like impedance and polarization were similar between groups. The results suggest that this design could improve long-term pacing performance. The authors do not claim the design is essential but propose it may offer benefits for clinical use.
Area of Science:
Background:
Threshold reduction in pacing leads is a known benefit of steroid-releasing systems. Earlier studies focused on passive fixation leads, but no long-term data existed for active fixation models. Researchers had not yet tested whether steroid-infused leads could improve active fixation performance. Prior evidence suggested that steroids reduce tissue reaction and pacing thresholds. However, the specific impact on active fixation leads remained unclear. This gap motivated the development of a new lead design with a drug-infused ceramic collar. The study aimed to evaluate the long-term effects of this modification in sheep models. The focus was on comparing threshold values between modified and standard leads.
Purpose Of The Study:
The goal was to assess whether a steroid-releasing ceramic collar could reduce pacing thresholds in active fixation leads. The study tested the hypothesis that dexamethasone acetate would improve lead performance over time. Researchers compared modified and standard leads in both atrial and ventricular configurations. They measured threshold values at 24 weeks to evaluate long-term stability. The study aimed to determine if the drug-infused collar could lower energy requirements. Researchers also wanted to confirm whether other parameters remained unchanged. The primary outcome was the comparison of bipolar thresholds between groups. The study sought to support the use of this design in clinical applications.
The study found that leads with a dexamethasone acetate-releasing collar had significantly lower pacing thresholds at 24 weeks.
The porous ceramic collar is infused with dexamethasone acetate to reduce tissue reaction and pacing thresholds.
The researchers used a sheep model to evaluate long-term lead performance in a large animal setting.
The study also measured pacing and sensing impedance, as well as polarization overpotential.
Main Methods:
The study used a long-term sheep model to test lead performance. Two types of leads were compared: standard Accufix and modified Accufix DEC. The modified leads featured a porous ceramic collar infused with dexamethasone acetate. Researchers implanted both atrial and ventricular versions of each lead. Thresholds were measured at 24 weeks using a 0.5-millisecond pulse width. Additional parameters included pacing and sensing impedance. Polarization overpotential was also evaluated for both groups. The sample size and statistical methods were not specified in the abstract.
Main Results:
Modified leads showed significantly lower thresholds than standard leads. At 24 weeks, ventricular thresholds were 0.51 ± 0.07 for DEC versus 1.49 ± 1.03 for ACC. Atrial thresholds were 1.31 ± 1.14 for DEC versus 2.99 ± 1.31 for ACC. These differences were statistically significant. Other parameters like impedance and polarization were similar between groups. The study found no evidence of increased complications with the modified leads. Thresholds remained stable over the 24-week period. The results suggest that the drug-infused collar effectively reduces energy needs. The findings support the potential for clinical use of this lead design.
Conclusions:
The study supports the use of steroid-releasing collars in active fixation leads. The authors propose that this design reduces pacing thresholds without affecting other parameters. They suggest that the collar may lower energy requirements for long-term pacing. The results indicate that the modified leads perform better than standard versions. The authors do not claim that this design is essential for all applications. They emphasize the need for further clinical validation. The study does not propose new drug targets or future research directions. The findings are limited to the sheep model and 24-week timeframe.
Thresholds were measured using a 0.5-millisecond pulse width at 24 weeks.
The authors suggest the modified leads may offer excellent potential for low energy stimulation.