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David S. Goldstein - One of the best experts on this subject based on the ideXlab platform.
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Long-term trends in myocardial Sympathetic Innervation and function in synucleinopathies.
Parkinsonism & related disorders, 2019Co-Authors: Guillaume Lamotte, Courtney Holmes, David S. GoldsteinAbstract:Abstract Introduction Parkinson disease (PD), pure autonomic failure (PAF), and multiple system atrophy (MSA) are characterized by intra-cerebral deposition of the protein alpha-synuclein and are termed synucleinopathies. Lewy body synucleinopathies involve decreased cardiac Sympathetic Innervation and functional abnormalities in residual noradrenergic terminals. This observational, retrospective, cohort study describes long-term trends in indices of cardiac Sympathetic Innervation and function in synucleinopathies. Methods Patients with PD (N = 31), PAF (N = 9), or MSA (N = 9) underwent repeated 18F-dopamine positron emission tomography (median follow-up 3.5 years). Interventricular septal 18F-dopamine-derived radioactivity 8 min after tracer injection (8′ Radioactivity) was used as an index of Sympathetic Innervation and the slope of mono-exponential decline of radioactivity between 8 and 25 min (k8’-25’) as an index of intraneuronal vesicular storage. Healthy volunteers (HVs) (N = 33) and individuals at high risk of PD (N = 15) were controls. Results Upon initial evaluation the groups with PD and orthostatic hypotension (OH), PAF, or PD and no OH had low mean 8′ Radioactivity compared to HVs (p Conclusions Neuroimaging evidence of decreased vesicular uptake in cardiac Sympathetic nerves is present upon initial evaluation of patients with Lewy body synucleinopathies and may provide a biomarker of catecholaminergic dysfunction early in the disease process.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Cleveland Clinic Journal of Medicine, 2009Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background. Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective. We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods. We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F]fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results. LF power was unrelated to myocardial 6-[ 18 F]fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P < 0.0001). Patients with a low BRS (≤ 3 msec/mm Hg) had low LF power, regardless of cardiac Innervation. Tyramine and yohimbine increased LF power in subjects with normal BRS but not in those with low BRS. BRS at baseline predicted LF responses to tyramine and yohimbine. Conclusion. LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Heart Rhythm, 2007Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F] fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results LF power was unrelated to myocardial 6-[ 18 F] fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P Conclusion LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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functional neuroimaging of Sympathetic Innervation of the heart
Annals of the New York Academy of Sciences, 2004Co-Authors: David S. GoldsteinAbstract:: Many concepts about acute and chronic effects of stress depend on alterations in Sympathetic nerves supplying the heart. Physiologic, pharmacologic, and neurochemical approaches have been used to evaluate cardiac Sympathetic function. This article describes a fourth approach that is based on nuclear scanning to visualize cardiac Sympathetic Innervation and function and relationships between the neuroimaging findings and those from other approaches. Multiple-system atrophy with orthostatic hypotension (formerly the Shy-Drager syndrome) features normal cardiac Sympathetic Innervation and normal entry of norepinephrine into the coronary sinus (cardiac norepinephrine spillover), in contrast to Parkinson disease with orthostatic hypotension, which features neuroimaging and neurochemical evidence for loss of cardiac Sympathetic nerves. This difference may have important implications not only for diagnosis but also for understanding the etiology of Parkinson disease. By analysis of curves relating myocardial radioactivity with time (time-activity curves) after injection of a sympathoneural imaging agent, it is possible to obtain information about cardiac Sympathetic function. Abnormal time-activity curves are seen in common disorders such as heart failure and diabetic neuropathy and provide an independent, adverse prognostic index. Analogous abnormalities might help explain increased cardiovascular risk in psychiatric disorders such as melancholic depression.
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Imaging of the autonomic nervous system: Focus on cardiac Sympathetic Innervation
Seminars in neurology, 2003Co-Authors: David S. GoldsteinAbstract:Symptoms or signs of abnormal autonomic nervous system function occur commonly in several neurological disorders. Clinical evaluations have depended on physiological, pharmacological, and neurochemical approaches. Recently, imaging of Sympathetic noradrenergic Innervation has been introduced and applied especially in the heart. Most studies have used the radiolabeled sympathomimetic amine, (123)I-metaiodobenzylguanidine. Decreased uptake or increased "washout" of (123)I-metaiodobenzylguanidine-derived radioactivity is associated with worse prognosis or more severe disease in hypertension, congestive heart failure, arrhythmias, and diabetes mellitus. This pattern may reflect a high rate of postganglionic Sympathetic nerve traffic to the heart. Many recent studies have agreed on the remarkable finding that all patients with Parkinson's disease and orthostatic hypotension have a loss of cardiac Sympathetic Innervation, whereas all patients with multiple system atrophy, often difficult to distinguish clinically from Parkinson's disease, have intact cardiac Sympathetic Innervation. Because Parkinson's disease entails a postganglionic Sympathetic noradrenergic lesion, the disease appears to be not only a movement disorder, with dopamine loss in the nigrostriatal system of the brain, but also a dysautonomia, with noradrenaline loss in the Sympathetic nervous system of the heart. As new ligands are developed, one may predict further discoveries of involvement of components of the autonomic nervous system in neurological diseases.
Yehonatan Sharabi - One of the best experts on this subject based on the ideXlab platform.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Cleveland Clinic Journal of Medicine, 2009Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background. Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective. We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods. We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F]fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results. LF power was unrelated to myocardial 6-[ 18 F]fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P < 0.0001). Patients with a low BRS (≤ 3 msec/mm Hg) had low LF power, regardless of cardiac Innervation. Tyramine and yohimbine increased LF power in subjects with normal BRS but not in those with low BRS. BRS at baseline predicted LF responses to tyramine and yohimbine. Conclusion. LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Heart Rhythm, 2007Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F] fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results LF power was unrelated to myocardial 6-[ 18 F] fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P Conclusion LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
Courtney Holmes - One of the best experts on this subject based on the ideXlab platform.
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Long-term trends in myocardial Sympathetic Innervation and function in synucleinopathies.
Parkinsonism & related disorders, 2019Co-Authors: Guillaume Lamotte, Courtney Holmes, David S. GoldsteinAbstract:Abstract Introduction Parkinson disease (PD), pure autonomic failure (PAF), and multiple system atrophy (MSA) are characterized by intra-cerebral deposition of the protein alpha-synuclein and are termed synucleinopathies. Lewy body synucleinopathies involve decreased cardiac Sympathetic Innervation and functional abnormalities in residual noradrenergic terminals. This observational, retrospective, cohort study describes long-term trends in indices of cardiac Sympathetic Innervation and function in synucleinopathies. Methods Patients with PD (N = 31), PAF (N = 9), or MSA (N = 9) underwent repeated 18F-dopamine positron emission tomography (median follow-up 3.5 years). Interventricular septal 18F-dopamine-derived radioactivity 8 min after tracer injection (8′ Radioactivity) was used as an index of Sympathetic Innervation and the slope of mono-exponential decline of radioactivity between 8 and 25 min (k8’-25’) as an index of intraneuronal vesicular storage. Healthy volunteers (HVs) (N = 33) and individuals at high risk of PD (N = 15) were controls. Results Upon initial evaluation the groups with PD and orthostatic hypotension (OH), PAF, or PD and no OH had low mean 8′ Radioactivity compared to HVs (p Conclusions Neuroimaging evidence of decreased vesicular uptake in cardiac Sympathetic nerves is present upon initial evaluation of patients with Lewy body synucleinopathies and may provide a biomarker of catecholaminergic dysfunction early in the disease process.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Cleveland Clinic Journal of Medicine, 2009Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background. Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective. We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods. We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F]fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results. LF power was unrelated to myocardial 6-[ 18 F]fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P < 0.0001). Patients with a low BRS (≤ 3 msec/mm Hg) had low LF power, regardless of cardiac Innervation. Tyramine and yohimbine increased LF power in subjects with normal BRS but not in those with low BRS. BRS at baseline predicted LF responses to tyramine and yohimbine. Conclusion. LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Heart Rhythm, 2007Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F] fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results LF power was unrelated to myocardial 6-[ 18 F] fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P Conclusion LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
Jeffrey P Moak - One of the best experts on this subject based on the ideXlab platform.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Cleveland Clinic Journal of Medicine, 2009Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background. Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective. We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods. We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F]fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results. LF power was unrelated to myocardial 6-[ 18 F]fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P < 0.0001). Patients with a low BRS (≤ 3 msec/mm Hg) had low LF power, regardless of cardiac Innervation. Tyramine and yohimbine increased LF power in subjects with normal BRS but not in those with low BRS. BRS at baseline predicted LF responses to tyramine and yohimbine. Conclusion. LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Heart Rhythm, 2007Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F] fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results LF power was unrelated to myocardial 6-[ 18 F] fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P Conclusion LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
Sandra Pechnik - One of the best experts on this subject based on the ideXlab platform.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Cleveland Clinic Journal of Medicine, 2009Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background. Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective. We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods. We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F]fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results. LF power was unrelated to myocardial 6-[ 18 F]fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P < 0.0001). Patients with a low BRS (≤ 3 msec/mm Hg) had low LF power, regardless of cardiac Innervation. Tyramine and yohimbine increased LF power in subjects with normal BRS but not in those with low BRS. BRS at baseline predicted LF responses to tyramine and yohimbine. Conclusion. LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
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supine low frequency power of heart rate variability reflects baroreflex function not cardiac Sympathetic Innervation
Heart Rhythm, 2007Co-Authors: Jeffrey P Moak, David S. Goldstein, Courtney Holmes, Basil A Eldadah, Ahmed Saleem, Sandra Pechnik, Yehonatan SharabiAbstract:Background Power spectral analysis of heart rate variability (HRV) has been used to indicate cardiac autonomic function. High-frequency power relates to respiratory sinus arrhythmia and therefore to paraSympathetic cardiovagal tone; however, the relationship of low-frequency (LF) power to cardiac Sympathetic Innervation and function has been controversial. Alternatively, LF power might reflect baroreflexive modulation of autonomic outflows. Objective We studied normal volunteers and chronic autonomic failure syndrome patients with and without loss of cardiac noradrenergic nerves to examine the relationships of LF power with cardiac Sympathetic Innervation and baroreflex function. Methods We compared LF power of HRV in patients with cardiac Sympathetic denervation, as indicated by low myocardial concentrations of 6-[ 18 F] fluorodopamine-derived radioactivity or low rates of norepinephrine entry into coronary sinus plasma (cardiac norepinephrine spillover) to values in patients with intact Innervation, at baseline, during infusion of yohimbine, which increases exocytotic norepinephrine release from Sympathetic nerves, or during infusion of tyramine, which increases non-exocytotic release. Baroreflex-cardiovagal slope (BRS) was calculated from the cardiac interbeat interval and systolic pressure during the Valsalva maneuver. Results LF power was unrelated to myocardial 6-[ 18 F] fluorodopamine-derived radioactivity or cardiac norepinephrine spillover. In contrast, the log of LF power correlated positively with the log of BRS (r = 0.72, P Conclusion LF power reflects baroreflex function, not cardiac Sympathetic Innervation.
