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Rate-responsive ventricular pacing: clinical experience with the RS4-SRT pacing system
Pacing and Clinical Electrophysiology : PACE
|May 1, 1985
Summary
The RS4-SRT pacing system, intended for atrioventricular block, showed unreliable rate-responsiveness due to sensing issues. This pacing system did not improve exercise tolerance compared to standard VVI pacing.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Symptomatic atrioventricular block necessitates pacing solutions.
- Rate-responsive pacing aims to optimize cardiac output during physical activity.
Purpose of the Study:
- To evaluate the efficacy of the RS4-SRT pacing system in patients with atrioventricular block.
- To compare exercise tolerance with RS4 mode versus VVI mode pacing.
Main Methods:
- Eighteen patients with second or third-degree atrioventricular block were implanted with the RS4-SRT system.
- Randomized double-blind treadmill stress testing compared RS4 and VVI modes.
- Post-discharge assessment included exercise testing and Holter monitoring.
Main Results:
- Implantation challenges included difficulty obtaining adequate P-wave amplitudes, leading to longer procedure times.
- 58% of patients exhibited a significant ventricular rate response to exercise in RS4 mode.
- While peak heart rate and double product improved in RS4 responders, exercise duration and work done were not significantly different compared to VVI mode.
Conclusions:
- The RS4-SRT pacing system demonstrated unreliable atrial sensing, compromising its rate-responsive function.
- The system failed to provide sufficient rate-responsiveness to enhance exercise tolerance in patients with atrioventricular block.
