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Comparison of spontaneous vs. metronome-guided breathing on assessment of vagal modulation using RR variability
- Source :
- American journal of physiology. Heart and circulatory physiology. 280(3)
- Publication Year :
- 2001
-
Abstract
- R-R interval variability (RR variability) is increasingly being used as an index of autonomic activity. High-frequency (HF) power reflects vagal modulation of the sinus node. Since vagal modulation occurs at the respiratory frequency, some investigators have suggested that HF power cannot be interpreted unless the breathing rate is controlled. We hypothesized that HF power during spontaneous breathing would not differ significantly from HF power during metronome-guided breathing. We measured HF power during spontaneous breathing in 20 healthy subjects and 19 patients with heart disease. Each subject's spontaneous breathing rate was determined, and the calculation of HF power was repeated with a metronome set to his or her average spontaneous breathing rate. There was no significant difference between the logarithm of HF power measured during spontaneous and metronome-guided breathing [4.88 ± 0.29 vs. 5.29 ± 0.30 ln(ms2), P = 0.32] in the group as a whole and when patients and healthy subjects were examined separately. We did observe a small (9.9%) decrease in HF power with increasing metronome-guided breathing rates (from 9 to 20 breaths/min). These data indicate that HF power during spontaneous and metronome-guided breathing differs at most by very small amounts. This variability is several logarithmic units less than the wide discrepancies observed between healthy subjects and cardiac patients with a heterogeneous group of cardiovascular disorders. In addition, HF power is relatively constant across the range of typical breathing rates. These data indicate that there is no need to control breathing rate to interpret HF power when RR variability (and specifically HF power) is used to identify high-risk cardiac patients.
- Subjects :
- Adult
Male
medicine.medical_specialty
Physiology
Coronary Disease
Metronome
law.invention
Parasympathetic nervous system
Electrocardiography
law
Heart Rate
Physiology (medical)
Internal medicine
Heart rate
medicine
Heart rate variability
Humans
Aged
Sinoatrial Node
medicine.diagnostic_test
business.industry
Respiration
digestive, oral, and skin physiology
Vagus Nerve
Middle Aged
Vagus nerve
Autonomic nervous system
medicine.anatomical_structure
Endocrinology
Breathing
Cardiology
Female
Cardiology and Cardiovascular Medicine
business
Subjects
Details
- ISSN :
- 03636135
- Volume :
- 280
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- American journal of physiology. Heart and circulatory physiology
- Accession number :
- edsair.doi.dedup.....83e9a059e4a585c039f43ca0404e65d1