Abstract
Patients with essential hypertension often show alterations of the autonomic nervous system. We evaluated the sympathetic and parasympathetic drive to the heart in 12 mildly hypertensive patients and 9 healthy subjects by power spectral analysis of heart rate variability. All subjects underwent measurements of RR interval, low (LF) and high frequency (HF) components of heart rate variability, LF/HF ratio and blood pressure in the resting and sitting positions, both before and after oral clonidine (300 μg), a central sympatholytic agent. In the supine position before clonidine, hypertensive patients had higher blood pressure and lower HF values than healthy subjects. Clonidine induced increases in RR interval and HF in both groups, while LF and LF/HF ratio decreased in healthy subjects, but not in hypertensive patients. On assuming the sitting position, both groups showed reductions in RR and HF and increments in LF and LF/HF. In healthy subjects, the response to the postural challenge was unaffected by clonidine. In contrast, hypertensive patients showed no changes in LF and LF/HF ratio, and a significantly lower decrease in HF. These differences were probably due to the existence of two subsets of patients, one exhibiting similar responses to clonidine as healthy subjects, and the other showing no appreciable response to the drug. These results suggest that hypertensive patients have an altered sympatho-vagal balance to the heart, which can be unmasked by clonidine. This phenomenon should be taken into account to achieve a better control of the overall cardiovascular risk of hypertensive patients. Copyright (C) 1998 Elsevier Science B.V.
| Original language | English |
|---|---|
| Pages (from-to) | 152-159 |
| Number of pages | 8 |
| Journal | Journal of the Autonomic Nervous System |
| Volume | 74 |
| Issue number | 2-3 |
| DOIs | |
| Publication status | Published - Dec 11 1998 |
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Keywords
- Autonomic nervous system
- Clonidine
- Essential hypertension
- Power spectral analysis
ASJC Scopus subject areas
- Physiology
- Clinical Neurology
- Neuroscience(all)
Cite this
Effects of clonidine on power spectral analysis of heart rate variability in mild essential hypertension. / Lazzeri, Chiara; La Villa, Giorgio; Mannelli, Massimo; Janni, Lucia; Barletta, Giuseppe; Montano, Nicola; Franchi, Franco.
In: Journal of the Autonomic Nervous System, Vol. 74, No. 2-3, 11.12.1998, p. 152-159.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of clonidine on power spectral analysis of heart rate variability in mild essential hypertension
AU - Lazzeri, Chiara
AU - La Villa, Giorgio
AU - Mannelli, Massimo
AU - Janni, Lucia
AU - Barletta, Giuseppe
AU - Montano, Nicola
AU - Franchi, Franco
PY - 1998/12/11
Y1 - 1998/12/11
N2 - Patients with essential hypertension often show alterations of the autonomic nervous system. We evaluated the sympathetic and parasympathetic drive to the heart in 12 mildly hypertensive patients and 9 healthy subjects by power spectral analysis of heart rate variability. All subjects underwent measurements of RR interval, low (LF) and high frequency (HF) components of heart rate variability, LF/HF ratio and blood pressure in the resting and sitting positions, both before and after oral clonidine (300 μg), a central sympatholytic agent. In the supine position before clonidine, hypertensive patients had higher blood pressure and lower HF values than healthy subjects. Clonidine induced increases in RR interval and HF in both groups, while LF and LF/HF ratio decreased in healthy subjects, but not in hypertensive patients. On assuming the sitting position, both groups showed reductions in RR and HF and increments in LF and LF/HF. In healthy subjects, the response to the postural challenge was unaffected by clonidine. In contrast, hypertensive patients showed no changes in LF and LF/HF ratio, and a significantly lower decrease in HF. These differences were probably due to the existence of two subsets of patients, one exhibiting similar responses to clonidine as healthy subjects, and the other showing no appreciable response to the drug. These results suggest that hypertensive patients have an altered sympatho-vagal balance to the heart, which can be unmasked by clonidine. This phenomenon should be taken into account to achieve a better control of the overall cardiovascular risk of hypertensive patients. Copyright (C) 1998 Elsevier Science B.V.
AB - Patients with essential hypertension often show alterations of the autonomic nervous system. We evaluated the sympathetic and parasympathetic drive to the heart in 12 mildly hypertensive patients and 9 healthy subjects by power spectral analysis of heart rate variability. All subjects underwent measurements of RR interval, low (LF) and high frequency (HF) components of heart rate variability, LF/HF ratio and blood pressure in the resting and sitting positions, both before and after oral clonidine (300 μg), a central sympatholytic agent. In the supine position before clonidine, hypertensive patients had higher blood pressure and lower HF values than healthy subjects. Clonidine induced increases in RR interval and HF in both groups, while LF and LF/HF ratio decreased in healthy subjects, but not in hypertensive patients. On assuming the sitting position, both groups showed reductions in RR and HF and increments in LF and LF/HF. In healthy subjects, the response to the postural challenge was unaffected by clonidine. In contrast, hypertensive patients showed no changes in LF and LF/HF ratio, and a significantly lower decrease in HF. These differences were probably due to the existence of two subsets of patients, one exhibiting similar responses to clonidine as healthy subjects, and the other showing no appreciable response to the drug. These results suggest that hypertensive patients have an altered sympatho-vagal balance to the heart, which can be unmasked by clonidine. This phenomenon should be taken into account to achieve a better control of the overall cardiovascular risk of hypertensive patients. Copyright (C) 1998 Elsevier Science B.V.
KW - Autonomic nervous system
KW - Clonidine
KW - Essential hypertension
KW - Power spectral analysis
UR - http://www.scopus.com/inward/record.url?scp=0032435864&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032435864&partnerID=8YFLogxK
U2 - 10.1016/S0165-1838(98)00148-9
DO - 10.1016/S0165-1838(98)00148-9
M3 - Article
C2 - 9915631
AN - SCOPUS:0032435864
VL - 74
SP - 152
EP - 159
JO - Journal of the Autonomic Nervous System
JF - Journal of the Autonomic Nervous System
SN - 0165-1838
IS - 2-3
ER -