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Updated: Jun 16, 2026
11:40
Quantitative Autonomic Testing
Published on: July 19, 2011
Chronotropic incompetence and autonomic dysfunction in patients without structural heart disease
Tatsuya Kawasaki1, Satoshi Kaimoto, Tomohiko Sakatani
1Department of Cardiology, Matsushita Memorial Hospital, Sotojima 5-55, Moriguchi, Osaka 570-8540, Japan. js-k@wf6.so-net.ne.jp
Summary
Chronotropic incompetence (CI), an impaired heart rate response to exercise, is linked to autonomic dysfunction. Patients with CI show greater sympathetic activation during exercise, suggesting a potential issue in how the body translates this to heart rate.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
- Exercise Physiology
Background:
- Chronotropic incompetence (CI) is an attenuated heart rate response to exercise.
- CI is an independent predictor of cardiovascular mortality.
- Autonomic function during exercise testing is crucial for understanding CI.
Purpose of the Study:
- To examine changes in autonomic function during exercise testing.
- To correlate these autonomic changes with chronotropic incompetence (CI).
Main Methods:
- 172 patients without cardiac disease underwent bicycle ergometer exercise testing.
- CI defined by heart rate response metrics (max HR, HR reserve, chronotropic response index).
- Analyzed heart rate variability (HRV) components (HF, LF/HF ratio) before and after exercise.
Main Results:
- HRV indexes were similar before exercise in patients with and without CI.
- Patients with CI exhibited a significantly higher percentage increase in the LF/HF ratio post-exercise (sympathovagal balance index).
- Percentage changes in the HF component (vagal modulation) were similar between groups.
Conclusions:
- CI in patients without structural heart disease may stem from sympathetic activation not effectively increasing heart rate.
- This suggests a potential issue in the beta-adrenergic receptor pathway's post-synaptic sensitivity.
- Further research is warranted to elucidate the precise mechanisms of CI.
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