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Time course of transvenous pacemaker stimulation impedance, capture threshold, and electrogram amplitude
Pacing and Clinical Electrophysiology : PACE
|September 1, 1986
Summary
This study shows that noninvasive telemetry accurately measures pacemaker function. Pacing impedance decreases over time, while capture thresholds initially rise then fall, with stable electrogram amplitudes.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- Dual-chamber pacemakers are crucial for managing bradyarrhythmias.
- Accurate monitoring of pacing lead parameters is essential for optimal device function and patient outcomes.
- Noninvasive telemetry offers a convenient method for assessing pacemaker performance.
Purpose of the Study:
- To evaluate the time-dependent changes in atrial and ventricular stimulation impedance, capture thresholds, and electrogram amplitudes using noninvasive telemetry.
- To validate the accuracy of telemetric measurements against invasive measurements from a pacing system analyzer.
- To assess the long-term stability of pacing parameters in patients with dual-chamber pacemakers.
Main Methods:
- Noninvasive telemetric data were collected from 63 patients implanted with unipolar, endocardial pacing leads and a second-generation dual-chamber pacemaker.
- Data collected included stimulation impedance, electrograms, and automatic capture thresholds over a 9-20 month follow-up period.
- Telemetric measurements were compared with immediate post-implant invasive measurements using a pacing system analyzer.
Main Results:
- Significant correlation was found between acute telemetric and invasive measurements for both atrial and ventricular stimulation impedance (r = .7 and r = .8, respectively).
- Atrial and ventricular stimulation impedance decreased significantly over 13 months (p < .01).
- Capture thresholds peaked at one month post-implant before declining, while electrogram amplitudes remained stable.
Conclusions:
- Noninvasive telemetry provides accurate measurements of pacemaker lead parameters, correlating closely with invasive methods.
- Pacing lead impedance demonstrates a decreasing trend over time, while capture thresholds exhibit an initial increase followed by a decrease.
- Electrogram amplitudes remain stable, indicating consistent lead-tip to tissue contact and electrical conduction.