Temporal asymmetries of short-term heart period variability are linked to autonomic regulation

2008 ◽  
Vol 295 (2) ◽  
pp. R550-R557 ◽  
Author(s):  
A. Porta ◽  
K. R. Casali ◽  
A. G. Casali ◽  
T. Gnecchi-Ruscone ◽  
E. Tobaldini ◽  
...  
Keyword(s):  
Autonomic Regulation ◽  
Heart Period ◽  
Short Term ◽  
Time Reversibility ◽  
Heart Period Variability ◽  
Period Variability ◽  
Healthy Humans ◽  
Inclination Angles ◽  
Head Up Tilt ◽  
Important Shift

We exploit time reversibility analysis, checking the invariance of statistical features of a series after time reversal, to detect temporal asymmetries of short-term heart period variability series. Reversibility indexes were extracted from 22 healthy fetuses between 16th to 40th wk of gestation and from 17 healthy humans (aged 21 to 54, median = 28) during graded head-up tilt with table inclination angles randomly selected inside the set {15, 30, 45, 60, 75, 90}. Irreversibility analysis showed that nonlinear dynamics observed in short-term heart period variability are mostly due to asymmetric patterns characterized by bradycardic runs shorter than tachycardic ones. These temporal asymmetries were 1) more likely over short temporal scales than over longer, dominant ones; 2) more frequent during the late period of pregnancy (from 25th to 40th week of gestation); 3) significantly present in healthy humans at rest in supine position; 4) more numerous during 75 and 90° head-up tilt. Results suggest that asymmetric patterns observable in short-term heart period variability might be the result of a fully developed autonomic regulation and that an important shift of the sympathovagal balance toward sympathetic predominance (and vagal withdrawal) can increase their presence.

Short-term variability of blood pressure and heart rate in Guillain-Barreá syndrome without respiratory failure

1999 ◽  
Vol 96 (6) ◽  
pp. 613-621 ◽  
Author(s):  
Djillali ANNANE ◽  
Véronique BAUDRIE ◽  
Anne-Sophie BLANC ◽  
Dominique LAUDE ◽  
Jean-Claude RAPHAËL ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Respiratory Failure ◽  
Plasma Noradrenaline ◽  
Heart Period ◽  
Short Term ◽  
Heart Period Variability ◽  
Period Variability ◽  
Head Up Tilt ◽  
Short Term Variability

The effect of Guillain-Barré syndrome (GBS) on the short-term variability of blood pressure and heart rate was evaluated in six patients presenting with a moderate form of the syndrome, i.e. unable to stand up unaided and without respiratory failure, at the height of the disease and during recovery. The patients were compared with six age-matched healthy volunteers. During the acute phase of the syndrome, GBS patients exhibited a significant heart rate elevation (+26 beats/min compared with healthy subjects), but the acceleratory response to atropine, or to 60 ° head-up tilt, was maintained. Resting plasma noradrenaline levels were high in acute GBS, but the secretory response to tilt was preserved. Desensitization to noradrenaline was observed in acute GBS with a reduced pressor action of this α-adrenoceptor agonist. Blood pressure levels were normal and head-up tilt did not induce orthostatic hypotension in this moderate form of GBS. Power spectral analysis demonstrated marked alterations in cardiovascular variability. The overall heart period variability was markedly reduced with the reduction predominantly in the high-frequency (respiratory) range (-73%). The low-frequency component of heart period variability was also reduced (-54%). This cardiovascular profile of moderate GBS at the height of the disease could result from a demyelination of the reflex loop controlling respiratory oscillations in heart rate and from a desensitization of the arterial tree to an elevated plasma noradrenaline. Sympathetic nervous activation may contribute to the high resting heart rate in acute GBS.

Effects of digoxin and enalapril on heart period variability and response to head-up tilt in normal subjects

1993 ◽  
Vol 72 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Elizabeth S. Kaufman ◽  
Matthew S. Bosner ◽  
J.Thomas Bigger ◽  
Phyllis K. Stein ◽  
Robert E. Kleiger ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Heart Period ◽  
Heart Period Variability ◽  
Period Variability ◽  
Head Up Tilt

Role of short-term cardiovascular regulation in heart period variability: a modeling study

2003 ◽  
Vol 284 (4) ◽  
pp. H1479-H1493 ◽  
Author(s):  
Mauro Ursino ◽  
Elisa Magosso
Keyword(s):  
Low Frequency ◽  
Cardiovascular Regulation ◽  
Mechanical Effect ◽  
Physiological Data ◽  
Model Parameters ◽  
Heart Period ◽  
Short Term ◽  
Heart Period Variability ◽  
Period Variability ◽  
Parameter Values

A mathematical model of short-term cardiovascular regulation is used to investigate how heart period variability reflects the action of the autonomic regulatory mechanisms (vagal and sympathetic). The model includes the pulsating heart, the systemic (splanchnic and extrasplanchnic) and pulmonary circulation, the mechanical effect of respiration on venous return, two groups of receptors (arterial baroreceptors and lung stretch receptors), the sympathetic and vagal efferent branches, and a very low-frequency (LF) vasomotor noise. All model parameters were given on the basis of physiological data from the literature. We used data from humans whenever possible, whereas parameters for the regulation loops are derived from dog experiments. The model, with basal parameter values, produces a heart period power spectrum with two distinct peaks [a high frequency (HF) peak at the respiratory rate and a LF peak at ∼0.1 Hz]. Sensitivity analysis on the mechanism gains suggests that the HF peak is mainly affected by the vagal mechanism, whereas the LF peak is increased by a high sympathetic gain and reduced by a high vagal gain. Moreover, the LF peak depends significantly on the reactivity of resistance vessels and is affected by noise, amplified by the sympathetic control loop at its resonance frequency. The model may represent a new tool to study alterations in the heart period spectrum on the basis of quantitative physiological hypotheses.

Progressive decrease of heart period variability entropy-based complexity during graded head-up tilt

2007 ◽  
Vol 103 (4) ◽  
pp. 1143-1149 ◽  
Author(s):  
Alberto Porta ◽  
Tomaso Gnecchi-Ruscone ◽  
Eleonora Tobaldini ◽  
Stefano Guzzetti ◽  
Raffaello Furlan ◽  
...  
Keyword(s):  
Complexity Analysis ◽  
Conditional Entropy ◽  
Approximate Entropy ◽  
Tilt Test ◽  
Sympathovagal Balance ◽  
Heart Period ◽  
Progressive Decrease ◽  
Heart Period Variability ◽  
Period Variability ◽  
Head Up Tilt

Complexity (or its opposite, regularity) of heart period variability has been related to age and disease but never linked to a progressive shift of the sympathovagal balance. We compare several well established estimates of complexity of heart period variability based on entropy rates [i.e., approximate entropy (ApEn), sample entropy (SampEn), and correct conditional entropy (CCE)] during an experimental protocol known to produce a gradual shift of the sympathovagal balance toward sympathetic activation and vagal withdrawal (i.e., the graded head-up tilt test). Complexity analysis was carried out in 17 healthy subjects over short heart period variability series (∼250 cardiac beats) derived from ECG recordings during head-up tilt with table inclination randomly chosen inside the set {0, 15, 30, 45, 60, 75, 90}. We found that 1) ApEn does not change significantly during the protocol; 2) all indices measuring complexity based on entropy rates, including ad hoc corrections of the bias arising from their evaluation over short data sequences (i.e., corrected ApEn, SampEn, CCE), evidence a progressive decrease of complexity as a function of the tilt table inclination, thus indicating that complexity is under control of the autonomic nervous system; 3) corrected ApEn, SampEn, and CCE provide global indices that can be helpful to monitor sympathovagal balance.

Role of the autonomic nervous system in generating non-linear dynamics in short-term heart period variability

2006 ◽  
Vol 51 (4) ◽  
pp. 174-177 ◽  
Author(s):  
Alberto Porta ◽  
Stefano Guzzetti ◽  
Ester Borroni ◽  
Raffaello Furlan ◽  
Nicola Montano ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Heart Period ◽  
Short Term ◽  
Linear Dynamics ◽  
Autonomic Nervous ◽  
Heart Period Variability ◽  
Period Variability ◽  
Non Linear

scholarly journals Visualization of Short-Term Heart Period Variability with Network Tools as a Method for Quantifying Autonomic Drive

2017 ◽  
pp. 141-158 ◽  
Author(s):  
Danuta Makowiec ◽  
Beata Graff ◽  
Agnieszka Kaczkowska ◽  
Grzegorz Graff ◽  
Dorota Wejer ◽  
...  
Keyword(s):  
Heart Period ◽  
Short Term ◽  
Heart Period Variability ◽  
Period Variability
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