scholarly journals Statin therapy restores sympathovagal balance in experimental heart failure

2003 ◽  
Vol 95 (2) ◽  
pp. 700-704 ◽  
Author(s):  
Rainer U. Pliquett ◽  
Kurtis G. Cornish ◽  
Irving H. Zucker
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Power Spectral Analysis ◽  
Total Power ◽  
Autonomic Balance ◽  
Autonomic Tone ◽  
Before And After ◽  
Autonomic Blockade ◽  
Coa Reductase ◽  
Constitutive Nitric Oxide Synthase

Inhibitors of hydroxymethylglutaryl-CoA reductase or statins have been shown to alleviate endothelial dysfunction. Their effects on constitutive nitric oxide synthase in the central nervous system may hypothetically affect the autonomic balance in sympathoexcitatory states, such as chronic heart failure (CHF). To address this issue, simvastatin (SIM) (0.3, 1.5, or 3 mg · kg-1 · day-1 po) was given to rabbits with pacing-induced CHF over a 3-wk period. Normal and CHF vehicle-treated rabbits served as controls. Autonomic balance was assessed by measuring heart rate variability, including power spectral analysis (PSA). In addition, changes in resting heart rate were assessed before and after vagal and sympathetic autonomic blockade by atropine and metoprolol, respectively. The SD for all intervals was 8.9 ± 0.7 ms in normal, 4.9 ± 0.6 ms in CHF ( P < 0.01), 3.8 ± 0.6 ms in CHF with 0.3 mg · kg-1 · day-1 SIM ( P < 0.001), 5.7 ± 0.9 in CHF with 1.5 mg · kg-1 · day-1 SIM ( P < 0.05), and 7.2 ± 0.5 in CHF with 3.0 mg · kg-1 · day-1 SIM. Similarly, total power was 40.5 ± 6.3 ms2 in normal, 10.1 ± 3.0 ms2 in CHF ( P < 0.01), 6.0 ± 1.6 ms2 in CHF with 0.3 mg · kg-1 · day-1 SIM ( P < 0.01), 13.2 ± 3.9 ms2 in CHF with 1.5 mg · kg-1 · day-1 SIM ( P < 0.05), and 22.0 ± 3.0 ms2 in CHF with 3.0 mg · kg-1 · day-1 SIM. Both PSA data for low (0.625–0.1875 Hz) and high frequencies (0.1875–0.5625 Hz) showed recovery in CHF animals on medium and high SIM doses without changes in the low-to-high-frequency ratio. SIM beneficially affects autonomic tone in CHF as seen by the reversal of depressed HRV and total power of PSA. These data have important implications for the treatment of patients with autonomic imbalance.

Effect of autonomic blockade on power spectrum of heart rate variability during exercise

1997 ◽  
Vol 273 (2) ◽  
pp. R495-R502 ◽  
Author(s):  
J. H. Warren ◽  
R. S. Jaffe ◽  
C. E. Wraa ◽  
C. L. Stebbins
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Power Spectra ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Total Power ◽  
Work Intensity ◽  
Autonomic Blockade ◽  
Low Frequency Power ◽  
Frequency Power

To validate power spectral analysis of heart rate variability (HRV) as an autonomic indicator during exercise, ten males performed four identical progressive cycling tests during infusions of saline, esmolol (beta 1-blocker), glycopyrrolate (muscarinic blocker), or both drugs. Power spectra were constructed from the recorded electrocardiogram by Fourier algorithm and integrated for low-frequency power (LF) and high-frequency power (HF). Four different LF bands (0.004-0.1, 0.004-0.15, 0.05-0.1, and 0.05-0.15 Hz) and two different HF bands (0.1-1.0 and 0.15-1.0 Hz) were evaluated. The parasympathetic index, HF, decreased exponentially with workload and was attenuated by glycopyrrolate and combined treatments with both HF frequency bands measured. Whereas some sympathetic indexes (LF/total power and LF/HF) did reflect expected increases in sympathetic nerve activity associated with progressive increases in work intensity, none of the measured increases responded appropriately to autonomic blockade. It is concluded that HRV is a valid technique for noninvasive measurement of parasympathetic tone during exercise, but its validity as a measure of sympathetic tone during exercise is equivocal.

scholarly journals Unilateral renal denervation improves autonomic balance in conscious rabbits with chronic heart failure

2013 ◽  
Vol 305 (8) ◽  
pp. R886-R892 ◽  
Author(s):  
Alicia M. Schiller ◽  
Karla K. V. Haack ◽  
Peter R. Pellegrino ◽  
Pamela L. Curry ◽  
Irving H. Zucker
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Chronic Heart Failure ◽  
Renal Denervation ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Symptomatic Improvement ◽  
Sympathetic Tone ◽  
Autonomic Balance ◽  
Protective Mechanisms

A hallmark of chronic heart failure (CHF) is an increased sympathetic tone resulting in autonomic imbalance. Renal denervation (DNx) in CHF patients has resulted in symptomatic improvement, but the protective mechanisms remain unclear. We hypothesized in CHF, unilateral renal DNx would improve cardiac autonomic balance. The present study used conscious, chronically instrumented New Zealand White rabbits undergoing renal DNx prior to pacing-induced CHF. Four treatment groups were used: nonpace, non-DNx [Sham-Innervated (Sham-INV)], nonpace DNx (sham-DNx), pace non-DNx (CHF-INV) or pace DNx (CHF-DNx). We examined several markers indicative of autonomic balance. Baroreflex sensitivity and time domain heart rate variability (HRV) were both decreased in the CHF-INV group compared with sham-INV and were restored to sham levels by renal DNx. Power spectral analysis indicated an increase in low-frequency/high-frequency (LF/HF) ratio in the CHF-INV compared with the sham-INV, which was normalized to sham levels by DNx. To assess whether this was due to a withdrawal of sympathetic tone or an increase in parasympathetic tone, the heart rate response was measured after an intravenous bolus of metoprolol or atropine. Bradycardia induced by intravenous metoprolol (indicative of cardiac sympathetic tone) was exacerbated in CHF-INV rabbits compared with sham-INV but was normalized in CHF-DNx. Conversely, the tachycardia in response to intravenous atropine (indicative of cardiac vagal tone) was not improved in CHF-DNx vs. CHF-INV animals. Renal DNx also prevented the increase in circulating plasma NE seen in CHF-INV rabbits. These results suggest renal DNx improves cardiac autonomic balance in CHF by a reduction of sympathetic tone.

scholarly journals Chromogranin A and the Autonomic System: Decomposition of Heart Rate Variability and Rescue by Its Catestatin Fragment

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2760-2768 ◽  
Author(s):  
Nagendu B. Dev ◽  
Jiaur R. Gayen ◽  
Daniel T. O'Connor ◽  
Sushil K. Mahata
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Chromogranin A ◽  
Baroreflex Sensitivity ◽  
Total Power ◽  
Systemic Hypertension ◽  
Autonomic Tone ◽  
Blood Pressure Elevation ◽  
System Decomposition ◽  
Before And After

Chromogranin A (CHGA/Chga) has been implicated in the genesis of systemic hypertension and consequent cardiac abnormalities. Catestatin (CST) (human CHGA352-372) replacement reduces blood pressure elevation and increases baroreflex sensitivity in Chga knockout (KO) mice. Because of the dampened baroreflex sensitivity, we reasoned that KO mice would display altered heart rate variability (HRV). Thus, we evaluated beat-to-beat measurements in HRV in wild-type (WT) and KO mice, before and after CST replacement. HR dynamics were evaluated by bipolar Einthoven electrocardiogram, with deconvolution into time and frequency domains, as well as Lorenz nonlinear return analyses. At baseline, HR was higher [444 ± 24 beats per minute (bpm)] in KO compared with WT (330 ± 18 bpm) mice. The total power in the HRV spectra was substantially diminished in KO animals. CST increased total power but only in KO mice. Each time-domain parameter was substantially lower in KO compared with WT mice, and the CST in the KO group could reverse the differences. Lorenz analysis revealed reductions in S1 (short axis perpendicular to the line of identity in the ellipse) and S2 (long axis along the line of identity in the ellipse) in KO animals, indicating that regulation of HRV is diminished in the parasympathetic and sympathetic domains. CST replacement caused restoration of both S1 and S2, in the KO group. These data suggest that Chga has a profound effect on autonomic tone to the heart and that its CST fragment is responsible for such actions. The results suggest future strategies for intervention in cardiovascular disorders accompanied by adverse HRV profiles.

scholarly journals Respiratory-related heart rate variability in progressive experimental heart failure

2005 ◽  
Vol 289 (4) ◽  
pp. H1729-H1735 ◽  
Author(s):  
Sophie Motte ◽  
Myrielle Mathieu ◽  
Serge Brimioulle ◽  
Anne Pensis ◽  
Lynn Ray ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Left Ventricular ◽  
Right Atrial ◽  
Left Ventricular Ejection ◽  
Total Power ◽  
Progressive Heart Failure ◽  
Atrial Natriuretic

Heart failure is associated with autonomic imbalance, and this can be evaluated by a spectral analysis of heart rate variability. However, the time course of low-frequency (LF) and high-frequency (HF) heart rate variability changes, and their functional correlates during progression of the disease are not exactly known. Progressive heart failure was induced in 16 beagle dogs over a 7-wk period by rapid ventricular pacing. Spectral analysis of heart rate variability and respiration, echocardiography, hemodynamic measurements, plasma atrial natriuretic factor, and norepinephrine was obtained at baseline and every week, 30 min after pacing interruption. Progressive heart failure increased heart rate (from 91 ± 4 to 136 ± 5 beats/min; P < 0.001) and decreased absolute and normalized (percentage of total power) HF variability from week 1 and 2, respectively ( P < 0.01). Absolute LF variability did not change during the study until it disappeared in two dogs at week 7 ( P < 0.05). Normalized LF variability increased in moderate heart failure ( P < 0.01), leading to an increased LF-to-HF ratio ( P < 0.05), but decreased in severe heart failure ( P < 0.044; week 7 vs. week 5). Stepwise regression analysis revealed that among heart rate variables, absolute HF variability was closely associated with wedge pressure, right atrial and pulmonary arterial pressure, left ventricular ejection fraction and volume, ratio of maximal velocity of early (E) and atrial (A) mitral flow waves, left atrial diameter, plasma norepinephrine, and atrial natriuretic peptide (0.45 < r < 0.65, all P < 0.001). In tachycardia-induced heart failure, absolute HF heart rate variability is a more reliable indicator of cardiac dysfunction and neurohumoral activation than LF heart rate variability.

scholarly journals Power spectral analysis of heart rate variability in Bangladeshi healthy population of different age

2014 ◽  
Vol 30 (1) ◽  
pp. 11-15
Author(s):  
Qazi Farzana Akhter ◽  
Qazi Shamima Akhter ◽  
Farhana Rahman ◽  
Sybyla Ferdousi ◽  
Susmita Sinha
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Power Spectral Analysis ◽  
Autonomic Nerve ◽  
Total Power ◽  
Healthy Population ◽  
Cross Sectional ◽  
Power Spectral ◽  
Group A

Heart rate variability (HRV) has been considered as an indicator of autonomic nerve function status. We aimed to find out the reference values of heart rate variability by power spectral analysis in our healthy population of different age. This cross sectional study was conducted in the Department of Physiology, Dhaka Medical College, Dhaka from the period of July 2012 to June 2013. For this, 180 subjects were selected with the age ranging from 15-60 years. All the study subjects were divided into 3 different groups according to age (Group A: 15-30 years; Group B: 31-45 years; Group C: 46-60 years). Each group contained 60 subjects of which 30 were male and 30 were female. The subjects were selected from different areas of Dhaka city by personal contacts. Analysis of HRV parameters were done in Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. For statistical analysis, one way ANOVA, unpaired Students t-test and Pearson’s correlation coefficient test were performed by using SPSS (version-17) as applicable. LF nu, LF power and LF/HF were significantly (p<0.001) higher in group C in comparison to those of group A and B. Again Total power, HF power, HF nu (p<0.001) were significantly higher in group A and B in comparison to that of group C. This study concludes that cardiac parasympathetic activity was decreased and sympathetic activity was increased with aging.DOI: http://dx.doi.org/10.3329/bjpp.v30i1.20788 Bangladesh J Physiol Pharmacol 2014; 30(1):11-15

Dynamics of spectral components of heart rate variability during changes in autonomic balance

1998 ◽  
Vol 275 (1) ◽  
pp. H213-H219 ◽  
Author(s):  
Michael V. Højgaard ◽  
Niels-Henrik Holstein-Rathlou ◽  
Erik Agner ◽  
Jørgen K. Kanters
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Supine Position ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Frequency Domain Analysis ◽  
Autonomic Balance ◽  
Power Spectral ◽  
Normalized Units ◽  
Semiquantitative Method

Frequency domain analysis of heart rate variability (HRV) has been proposed as a semiquantitative method for assessing activities in the autonomic nervous system. We examined whether absolute powers, normalized powers, and the low frequency-to-high frequency ratio (LF/HF) derived from the HRV power spectrum could detect shifts in autonomic balance in a setting with low sympathetic nervous tone. Healthy subjects were examined for 3 h in the supine position during 1) control conditions ( n = 12), 2) acute β-blockade ( n = 11), and 3) chronic β-blockade ( n = 10). Heart rate fell during the first 40 min of the control session (72 ± 2 to 64 ± 2 beats/min; P < 0.005) and was even lower during acute and chronic β-blockade (56 ± 2 beats/min; P < 0.005). The powers of all spectral areas rose during the first 60 min in all three settings, more so with β-blockade ( P < 0.05). LF/HF was found to contain the same information as powers expressed in normalized units. LF/HF detected the shift in autonomic balance induced by β-blockade but not the change induced by supine position. In conclusion, none of the investigated measures derived from power spectral analysis comprehensively and consistently described the changes in autonomic balance.

Baro- and ventricular reflexes in conscious dogs subjected to chronic tachycardia

1992 ◽  
Vol 263 (4) ◽  
pp. H1084-H1089 ◽  
Author(s):  
J. S. Chen ◽  
W. Wang ◽  
K. G. Cornish ◽  
I. H. Zucker
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Congestive Heart Failure ◽  
Clinical Signs ◽  
Chronic Congestive Heart Failure ◽  
Ventricular Pacing ◽  
Arterial Baroreflex ◽  
Failure State ◽  
Before And After ◽  
Blood Pressure Responses

It has been well documented that the arterial baroreflex is depressed in chronic congestive heart failure. Furthermore, cardiopulmonary reflexes have also been shown to be depressed in heart failure. Because cardiac reflexes can be mediated by both mechanical and chemical stimuli, we undertook the current study to determine whether chemically activated cardiac reflexes (Bezold-Jarisch) are abnormally depressed in dogs with chronic heart failure at a point in time when arterial baroreflexes were clearly depressed. We studied heart rate and arterial pressure responses in 13 conscious instrumented dogs before and after chronic ventricular pacing at 250 beats/min for 4-5 wk. At the time the study was done each dog showed both hemodynamic and clinical signs of congestive heart failure. The arterial baroreflex was evaluated by analyzing the heart rate response to acute injections of phenylephrine and nitroglycerin. The Bezold-Jarisch reflex was assessed in nine dogs by determining the heart rate and blood pressure responses to intracoronary injections of various doses of veratridine. Arterial baroreflex responses were uniformly depressed following ventricular pacing. The phenylephrine slope was reduced by 55.8 +/- 6.9% (P < 0.001), and the nitroglycerin slope was reduced by 67.9 +/- 5.0% (P < 0.0001) in the heart failure state. Significant bradycardia and hypotension were seen at each dose of veratridine given (0.01, 0.1, and 0.4 microgram/kg). When compared with the prepaced control state, the magnitude of the hypotension was no different in the heart failure state in response to any dose of veratridine.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of radiofrequency catheter ablation of accessory pathways on autonomic tone in children

1999 ◽  
Vol 9 (4) ◽  
pp. 377-383 ◽  
Author(s):  
Ruchir Sehra ◽  
Joyce E. Hubbard ◽  
Susan P. Straka ◽  
Naomi S. Fineberg ◽  
Douglas P. Zipes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Catheter Ablation ◽  
Supraventricular Tachycardia ◽  
Radiofrequency Catheter Ablation ◽  
Autonomic Function ◽  
Accessory Pathways ◽  
Non Invasive ◽  
Autonomic Changes ◽  
Before And After ◽  
Autonomic Blockade

AbstractBackgroundRadiofrequency catheter ablation is standard treatment for children with re-entrant supraventricular tachycardias. Autonomic changes have been noted after such ablation for atrioventricular nodal re-entry tachycardia, but not as well documented with atrioventricular re-entry over an accessory pathway.Methods and resultsIn 10 normal paediatric volunteers and 12 children referred for electrophysiologic testing and radiofrequency ablation of supraventricular tachycardia, non-invasive autonomic function tests and tilt-table testing were performed, and the variability in 24-h heart rate was analysed. Patients with supraventricular tachycardia underwent these tests both 24–72 h before and 24 h after ablation. Patients with tachycardia underwent additional autonomic testing to assess the sensitivity of baroreceptors and the intrinsic heart rate with autonomic blockade immediately before and after ablation. One non-invasive autonomic function test, namely handgrip, demonstrated significant differences (p < 0.05) in diastolic blood pressure before and after ablation, though these values did not differ from controls. Significant decreases were noted in two indexes of the variability of heart rate before and after ablation (p < 0.05). Certain tilt test variables also demonstrated significant differences between controls and those with tachycardia subsequent to ablation. Intracardiac testing demonstrated changes (p < 0.05) in sinus cycle lengths, effective refractory periods and/or blood pressures at baseline and during testing of the sensitivity of baroreceptors before and after ablation. These changes were consistent with increased sympathetic or decreased parasympathetic tone. With autonomic blockade, these differences were abolished.ConclusionsCatheter ablation of accessory pathways in children was associated with changes consistent with increased sympathetic or decreased parasympathetic tone. These autonomic changes persisted 24 h after the ablation procedure.

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