Heart rate control of blood pressure variability in children: a study in subjects with fixed ventricular pacemaker rhythm

1998 ◽  
Vol 95 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Isabelle CONSTANT ◽  
Elizabeth VILLAIN ◽  
Dominique LAUDE ◽  
Arlette GIRARD ◽  
Isabelle MURAT ◽  
...  

1.To investigate the influence of heart rate variability on blood pressure variability, short-term variability in heart rate and blood pressure was studied in 10 children with fixed ventricular pacemaker rhythm (80 beats/min). Ten healthy children, in sinus rhythm, served as a reference population. 2.Arterial blood pressure and heart rate were measured continuously using a finger arterial device and an ECG respectively. Power spectra for heart rate and blood pressure (systolic and diastolic) were calculated in both supine and orthostatic positions. In addition, acute changes in blood pressure and heart rate during active standing were studied. 3.Healthy children exhibited considerable heart rate variability, which was slightly more pronounced in the supine position, while children with a fixed ventricular rate had no heart rate variability in either position. 4.Despite the differences in heart rate variability, mean systolic blood pressure and its variability profiles were poorly affected by the suppression of heart rate variability. The lack of autonomic control on the sinus node was associated with a reduction in magnitude of the changes in systolic blood pressure variability induced by orthostatic posture. 5.The suppression of heart rate fluctuations induced a noticeable decrease in diastolic blood pressure fluctuations, which was most conspicuous in the children with fixed cardiac rhythm when in the supine position. This may be explained by the lack of diastolic blood pressure fluctuations, physiologically due to heart rate fluctuations through the run-off effect: the longer the cardiac cycle, the greater the diastolic pressure decay. These results may challenge the classical theory of baroreflex-mediated diastolic blood pressure control described in adult patients. 6.During active standing, the early drop in systolic blood pressure was greater in subjects with fixed ventricular rhythm. A rise in heart rate of 36 beats/min was observed in the healthy subjects in response to active standing. 7.We conclude that in normal children, heart rate fluctuations increase the blood pressure variability rather than buffering it. However, during acute orthostatic stress, the abrupt baroreflex-mediated heart rate rise may partly compensate for the reduction in blood pressure.

2021 ◽  
pp. 1-14
Author(s):  
Stefan Duschek ◽  
Angela Bair ◽  
Alexandra Hoffmann ◽  
Josef Marksteiner ◽  
Casandra I. Montoro ◽  
...  

Abstract. This study investigated cardiovascular variability and stress reactivity in major depressive disorder (MDD). While previous research has documented reduced heart rate variability, knowledge about blood pressure variability in MDD remains scarce. Regarding reactivity, a particular focus was placed on the time courses of the cardiovascular responses, which may provide insight into the autonomic mechanisms underlying the hypo-reactivity expected in MDD. In 76 MDD patients and 71 healthy controls, blood pressure was continuously recorded at rest and during mental stress induced by a 3-min serial subtraction task. Compared to controls, patients exhibited lower systolic and diastolic blood pressure, heart rate variability, and systolic and diastolic blood pressure variability. Moreover, smaller stress-related changes in heart rate, systolic and diastolic blood pressure, and sensitivity of the cardiac baroreflex arose in patients. Cardiovascular parameters did not differ between patients using antidepressants and unmedicated patients. According to time-course analysis, reduced hemodynamic modulations in MDD mainly occurred after 50 s of the stress period. Low heart rate variability in MDD reflects deficient top-down integration of the brain mechanisms allowing flexible autonomic and behavioral control; diminished blood pressure variability is indicative of poor homeostatic capacity with respect to the regulation of blood pressure and organ perfusion. Moreover, blunted cardiovascular reactivity implies poor adjustment of energetic resources to internal and environmental demands and may be a correlate of deficient motivational dynamics characterizing MDD. While cardiovascular hypo-reactivity in MDD may be mediated by baroreflex and adrenergic mechanisms, the fast-acting parasympathetic system may play a subordinate role.


1982 ◽  
Vol 50 (1) ◽  
pp. 219-230 ◽  
Author(s):  
Richard J. Roberts ◽  
Theodore C. Weerts

This study was designed to determine if visualization of anger- and fear-provoking scenes produced differential physiological patterns similar to those produced by in vivo manipulations. Normotensive college students were selected on the basis of their responses to newly developed Anger and Fear/Anxiety questionnaires and for their ability to construct arousing scenes during a screening interview. In a 2 × 2 design (intensity × emotion), four scenes (high and low anger, high and low fear) were constructed individually for each of 16 subjects to imagine. Diastolic blood pressure, systolic blood pressure, and heart rate were monitored during visualization of each scene. Change in diastolic blood pressure was significantly greater for high anger than for high fear as predicted. Analysis of change in heart rate and systolic blood pressure showed significant effects for intensity only. These results provide further support for the concept of physiological differentiation in human emotion and suggest the utility of imagery for systematic study of human emotional responding.


2008 ◽  
Vol 295 (3) ◽  
pp. H1150-H1155 ◽  
Author(s):  
François Cottin ◽  
Claire Médigue ◽  
Yves Papelier

The aim of the study was to assess the instantaneous spectral components of heart rate variability (HRV) and systolic blood pressure variability (SBPV) and determine the low-frequency (LF) and high-frequency baroreflex sensitivity (HF-BRS) during a graded maximal exercise test. The first hypothesis was that the hyperpnea elicited by heavy exercise could entail a significant increase in HF-SBPV by mechanical effect once the first and second ventilatory thresholds (VTs) were exceeded. It was secondly hypothesized that vagal tone progressively withdrawing with increasing load, HF-BRS could decrease during the exercise test. Fifteen well-trained subjects participated in this study. Electrocardiogram (ECG), blood pressure, and gas exchanges were recorded during a cycloergometer test. Ventilatory equivalents were computed from gas exchange parameters to assess VTs. Spectral analysis was applied on cardiovascular series to compute RR and systolic blood pressure power spectral densities, cross-spectral coherence, gain, and α index of BRS. Three exercise intensity stages were compared: below (A1), between (A2), and above (A3) VTs. From A1 to A3, both HF-SBPV (A1: 45 ± 6, A2: 65 ± 10, and A3: 120 ± 23 mm2Hg, P < 0.001) and HF-HRV increased (A1: 20 ± 5, A2: 23 ± 8, and A3:40 ± 11 ms2, P < 0.02), maintaining HF-BRS (gain, A1: 0.68 ± 0.12, A2: 0.63 ± 0.08, and A3: 0.57 ± 0.09; α index, A1: 0.58 ± 0.08, A2: 0.48 ± 0.06, and A3: 0.50 ± 0.09 ms/mmHg, not significant). However, LF-BRS decreased (gain, A1: 0.39 ± 0.06, A2: 0.17 ± 0.02, and A3: 0.11 ± 0.01, P < 0.001; α index, A1: 0.46 ± 0.07, A2: 0.20 ± 0.02, and A3: 0.14 ± 0.01 ms/mmHg, P < 0.001). As expected, once VTs were exceeded, hyperpnea induced a marked increase in both HF-HRV and HF-SBPV. However, this concomitant increase allowed the maintenance of HF-BRS, presumably by a mechanoelectric feedback mechanism.


2006 ◽  
Vol 75 (1) ◽  
pp. 3-12 ◽  
Author(s):  
J. Mokrý ◽  
T. Remeňová ◽  
K. Javorka

The purpose of the study was to evaluate the changes of respiratory rate, systemic blood pressure and heart rate variability parameters (HRV) during orthostasis in anaesthetized rabbits. Furthermore, these changes were influenced by affecting the renin-angiotensin-aldosterone (RAA) system and autonomic nervous system (ANS) to study the mechanisms participating in activity of spectral frequency bands of HRV in rabbits. Ten adult rabbits (Chinchilla) were anaesthetized by ketamine and flunitrazepam. The systemic blood pressure, tidal volume and respiratory rate were measured. HRV was evaluated by microcomputer system VariaPulse TF3E. The R-R intervals were derived from the electrocardiogram signal from subcutaneous needle electrodes. The evaluation of HRV in very low (VLF; 0.01-0.05 Hz), low (LF; 0.05-0.15 Hz) and high frequency bands (HF; 0.15-2.0 Hz) was made and parameters of frequency and time analysis were calculated. The measurements were made in horizontal (supine) position, in orthostasis (the angle of 60 °) and again in supine position before and after enalapril (0.5 mg/kg b.w.), metipranolol (0.2 mg/kg b.w.), and after subsequent bilateral cervical vagotomy. The orthostasis in anaesthetized rabbits is accompanied by depression of respiratory rate reversed only by vagotomy. Furthermore, decrease of systemic blood pressure, unchanged heart rate and increased characteristics of heart rate variability were found, with predominant increase of spectral power in LF and VLF bands. This elevation can be eliminated only by complete blockade of ANS. Although the participation of ANS or RAA system in modification of individual HRV frequency bands is not as specific as in humans, we confirmed the participation of RAA system in determination of the VLF band.


2022 ◽  
Vol 28 (1) ◽  
Author(s):  
Linda P. Bolin ◽  
Amelia D. Saul ◽  
Lauren L. Bethune Scroggs ◽  
Carolyn Horne

Abstract Background Cardiovascular disease is one of the leading causes of death globally with hypertension being a primary cause of premature death from this disease process. Individuals with a family history of cardiovascular disease and hypertension are at a greater risk for developing the same sequela. Autonomic cardiac control is important in the level of cardiac function. One intervention that is effective in improving cardiovascular function is heart rate variability biofeedback training. The purpose of our study was to determine the effectiveness of heart rate biofeedback training on HRV and blood pressure in individuals with a family history of cardiovascular disease. Methods Thirty-four participants (76.5% female, 22.7 ± 4.3 years) completed a baseline assessment and training using an established short-term HRV protocol followed by two weeks of at-home paced breathing employing a smartphone application. The participants were then reassessed in a biofeedback clinic. Results The participants physiological measures showed a significant increase in means between pre and post intervention of SDNN (t (32) = 2.177, p =.037) and TP, (t (32) = 2.327 p = .026). Correlation noted a medium effect on diastolic blood pressure and high frequency heart rate variability, F, r = .41, n =33, p < .05. A multiple regression with all predictor variables in the model found no significance with diastolic and systolic blood pressure. Conclusions The findings from this pilot study demonstrated that a two-week paced breathing intervention may assist in reducing heart rate and diastolic blood pressure while improving heart rate variability.


Author(s):  
Rishman Tandi ◽  
Tanvi Kumar ◽  
Amritpal Singh Kahlon ◽  
Aaftab Sethi

Introduction: Acute coronary syndrome remains as one of the most important causes for morbidity and mortality in developed countries. Therefore, evidence-based management strategy is required to offset the loss of health during an acute coronary syndrome. An effective approach includes both medical and surgical methods. This study was conducted to evaluate the medical method of management. Objective: To study blood pressure and heart rate variability after administration of Ivabradine or metoprolol in cases with acute coronary syndrome. Materials and methods: The study was a Prospective single center observational study conducted in patients attending Cardiology Intensive Care Unit in Nayyar Heart and Superspecialty Hospital, a tertiary care centre located in an urban area. All patients with Acute coronary syndrome admitted to the emergency or cardiac care unit were analysed with ECG as a preliminary diagnostic test and confirmed with troponin markers. They were either given Ivabradine or Metoprolol. Baseline evaluation and follow up was done and necessary data was collected and analysed.   Results: 100 patients were included in the study out of which 50 were given Metoprolol (Group A) and 50 were given Ivabradine (Group B). Themean age of studied cases was found to be 66.54 years in group A and 68.69 years in group B. It was observed that there was a fall in heart rate by 26.8 beats per minute with beta blocker and 24.4 beats per minute with Ivabradine. In case of blood pressure measurement, in patients with beta blocker administration, there was a fall of 25 mm Hg in systolic blood pressure and 17 mm Hg in diastolic blood pressure However, with Ivabradine there was only a fall of 8mm Hg in systolic Blood pressure and 6 mm Hg in diastolic blood pressure. Conclusion: Although Metoprolol is the drug of choice to decrease heart rate and blood pressure in acute coronary syndrome, Ivabradine is being increasingly used in cases where beta blockers are contraindicated as it has similar efficacy in lowering heart rate without compromising contractility of cardiac muscle, thereby maintaining LVEF and blood pressure. Keywords: Acute coronary syndrome, Beta Blockers, Metoprolol, Ivabradine.


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