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[Cardiopulmonary stress: control of the function of frequency variable pacemaker systems]
N Treese1, M Coutinho, N Ophoff
1II. Medizinische Klinik, Johannes-Gutenberg-Universität, Mainz.
Zeitschrift Fur Kardiologie
|June 1, 1990
Summary
Rate-responsive VVIR pacing significantly enhances exercise capacity in patients with chronotropic incompetence. This pacing mode improves maximal oxygen uptake and delays the anaerobic threshold, leading to better exercise tolerance and duration.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Chronotropic incompetence limits exercise capacity.
- Rate-responsive pacing aims to improve cardiovascular function during physical activity.
Purpose of the Study:
- To assess the physiological benefits of rate-responsive VVIR pacing in patients with chronotropic incompetence.
- To quantify improvements in exercise capacity using cardiopulmonary exercise testing.
Main Methods:
- Cardiopulmonary exercise testing (CPET) was performed on 17 patients with chronotropic incompetence.
- Patients underwent exercise on a bicycle ergometer with pacemakers programmed to fixed-rate VVI and rate-responsive VVIR modes.
- Maximal oxygen uptake and anaerobic threshold were determined.
Main Results:
- VVIR pacing increased maximal exercise heart rate (74 to 118 bpm, p<0.001).
- Maximal oxygen uptake increased (14.3 to 18.3 ml/kg/min, p<0.04) and anaerobic threshold was delayed (10.6 to 14.6 ml/kg/min, p<0.04) with VVIR pacing.
- Improved aerobic capacity led to a 17% increase in exercise tolerance and 19% increase in exercise time.
Conclusions:
- Rate-responsive VVIR pacing significantly improves exercise capacity in patients with chronotropic incompetence.
- Cardiopulmonary exercise testing is a valuable tool for quantifying the benefits of rate-responsive pacing.