ΔHR/ΔWR derived from CPET; A novel predictor of 'off' symptom in Parkinson's disease
Kohsuke Yoshida1, Kazuki Takano2, Hiromi Tani2
1Department of Clinical Laboratory, Hyogo Prefectural Rehabilitation Hospital at Nishi-Harima, 1-7-1 Kouto, Shingu-cho, Tatsuno, Hyogo, 679-5165, Japan; Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2, Tomogaoka, Suma-ku, Kobe, Hyogo, 654-0142, Japan.
Insights
Chronotropic incompetence (CI) in Parkinson's disease (PD) patients correlates with worse daily living symptoms. Cardiopulmonary exercise testing can predict these symptom fluctuations.
Area of Science:
- Cardiology
- Neurology
- Exercise Physiology
Background:
- Chronotropic incompetence (CI) is the inability of the heart to adequately increase rate with activity.
- Parkinson's disease (PD) is a neurodegenerative disorder affecting motor control.
- Understanding CI's impact on PD symptoms is crucial for patient management.
Purpose of the Study:
- To investigate the relationship between chronotropic incompetence (CI) and the severity of daily living impairments in Parkinson's disease (PD) patients.
- To determine if cardiopulmonary exercise testing (CPET) can serve as a predictive index for symptom fluctuations in PD.
Main Methods:
- Thirty-six hospitalized Parkinson's disease patients underwent cardiopulmonary exercise testing (CPET) and electrocardiogram.
- CPET assessed exercise tolerance (ΔVO2/ΔWR, peak VO2/W) and chronotropic incompetence (CI) using ΔHR/ΔWR.
- Heart rate variability was analyzed, and UPDRS part II (off-on) scores were calculated.
Main Results:
- Patients with CI exhibited lower exercise tolerance (ΔVO2/ΔWR, peak VO2/W) compared to those without CI.
- CI was associated with decreased parasympathetic activity (HF power) and increased sympathetic activity (LF/HF ratio).
- The UPDRS part II (off-on) scores, reflecting daily living impairment, were significantly higher in patients with CI.
Conclusions:
- Chronotropic incompetence (CI) is linked to reduced exercise capacity and altered autonomic function in Parkinson's disease (PD).
- The severity of daily living fluctuations ('off-on' symptoms) in PD patients may be predicted by CPET-derived ΔHR/ΔWR.
- CPET offers a potential non-invasive tool for assessing and predicting functional status in PD.
Introduction:
Chronotropic incompetence (CI) is broadly defined as the inability of the heart to increase its rate commensurate with increased activity. In this study, we tried to clarify the link between CI and UPDRS part II (off-on), which was calculated by subtracting part II (on) from part II (off), in patients with Parkinson's disease (PD).
Methods:
Thirty-six hospitalized patients were examined by using cardiopulmonary exercise testing (CPET) for exercise tolerance (ΔVO2/ΔWR and peak VO2/W) and the presence of CI (ΔHR/ΔWR), and using electrocardiogram for heart rate variability.
Results:
We originally divided the patients into three groups; Group I (ΔHR/ΔWR x100 <15) (N = 3), Group II (15≥, <60) (N = 28), Group III (>60) (N = 5). Since Group I and III were significantly smaller and older than Group II, we focused and divided into two groups; Group II CI (+), the PD patients with CI (15≤ ΔHR/ΔWR x100 <35), and Group II CI (-), those patients without that (35≤ ΔHR/ΔWR x100 <60). ΔVO2/ΔWR and peak VO2/W in CI (+) patients was lower than CI (-) (P = 0.022 and P = 0.096, respectively). HF power (parasympathetic activity) tends to be decreased, whereas LF/HF ratio (sympathetic activity) was increased in CI (+) patients as compared with CI (-). The UPDRS part II (off-on) of CI (+) patients was significantly higher than CI (-) (P = 0.023).
Conclusions:
In PD patients, the difference between 'on' and 'off' in activities of daily living might be predicted by using ΔHR/ΔWR x100 obtained from CPET as an index.
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