Related Experiment Videos
Active fixation atrial leads: randomized comparison of two lead designs
G N Kay1, K Anderson, A E Epstein
1Department of Medicine, University of Alabama, Birmingham 35294.
Pacing and Clinical Electrophysiology : PACE
|August 1, 1989
Summary
Active fixation pacemaker leads with independent electrodes do not offer superior chronic pacing thresholds compared to screw-helix leads. This study found no significant differences in pacing or sensing between lead types over time.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- Active fixation leads reduce dislodgement in permanent pacemaker patients.
- Concerns exist regarding potential increases in chronic pacing thresholds due to tissue trauma from screw-helix designs.
- The comparative performance of active fixation leads with independent electrodes versus screw-helix designs for both fixation and stimulation is not well-established.
Purpose of the Study:
- To compare the acute and chronic atrial pacing and sensing characteristics of two unipolar active fixation leads.
- To evaluate leads with an electrically independent porous tip electrode versus leads using a screw-helix for both fixation and stimulation.
Main Methods:
- Prospective, randomized study comparing two active fixation lead types: Medtronic 6957J (active screw-helix) and Cordis 329-101P (inactive helix, porous tip electrode).
- Patients were randomized to receive one of the two lead types.
- Pacing thresholds, sensing characteristics (atrial electrogram amplitude, slew rate), and lead impedance were assessed at implantation, 6 weeks, and long-term follow-up.
Main Results:
- At implantation, the porous tip electrode lead showed a lower mean voltage threshold (0.61 V) compared to the screw-helix lead (1.05 V).
- No significant differences in atrial electrogram amplitude, slew rate, or lead impedance were observed between the groups at any time point.
- At 6-week and long-term follow-up (mean 16.2 months), both lead types demonstrated comparable mean threshold voltages, impedance, and atrial electrogram amplitudes.
Conclusions:
- Active fixation atrial leads with electrodes independent of the fixation mechanism do not offer superior chronic stimulation thresholds or sensing compared to screw-helix leads.
- The choice between these active fixation lead designs does not appear to significantly impact long-term atrial pacing and sensing performance.
- The theoretical concern of increased chronic pacing thresholds with screw-helix active fixation leads was not substantiated in this study.