Reduced parasympathetic control of heart rate in obese dogs

1995 ◽  
Vol 269 (2) ◽  
pp. H629-H637 ◽  
Author(s):  
B. N. Van Vliet ◽  
J. E. Hall ◽  
H. L. Mizelle ◽  
J. P. Montani ◽  
M. J. Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rate Control ◽  
Saturated Fat ◽  
Pressure Control ◽  
Resting Heart Rate ◽  
Arterial Blood ◽  
Parasympathetic Control ◽  
The Mean ◽  
Affect Heart Rate

We investigated why resting heart rate is elevated in dogs fed a high saturated fat diet for 12.7 +/- 1.8 wk. Obese dogs exhibited elevated body weight (59%), blood pressure (14%), and heart rate (25%). Differences in resting heart rate (control, 58 +/- 5 beats/min; obese, 83 +/- 7 beats/min) were abolished after hexamethonium, indicating an autonomic mechanism. Hexamethonium also reduced blood pressure in obese (20 +/- 4 mmHg) but not control (9 +/- 6 mmHg) animals. Propranolol did not affect heart rate in either group, excluding a beta-adrenergic mechanism. Subsequent administration of atropine increased heart rate more in control than in obese dogs (110 +/- 9 vs. 57 +/- 11 beats/min). The sensitivity of the cardiac limb of the baroreflex (Oxford method) was reduced by 46% in the obese group, confirming impairment of the parasympathetic control of heart rate. The standard deviation of blood pressure measurements was normal when expressed as a percentage of the mean arterial blood pressure (control, 11.2 +/- 0.4%; obese, 11.2 +/- 0.5%). Our results indicate that the development of obesity in dogs fed a high saturated fat diet is accompanied by an attenuated resting and reflex parasympathetic control of heart rate.

Regulation of arterial blood pressure in Australian tiger snakes

1978 ◽  
Vol 75 (1) ◽  
pp. 65-79 ◽  
Author(s):  
H. B. Lillywhite ◽  
R. S. Seymour
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Complete Recovery ◽  
Pressure Control ◽  
Pressure Regulation ◽  
Body Temperatures ◽  
Heating And Cooling ◽  
Arterial Blood ◽  
Preferred Temperatures ◽  
Head Up Tilt

1. Blood pressure was measured in the dorsal aorta of restrained, unanaesthetized tiger snakes (Notechis scutatus) at different body temperatures during graded, passive tilt. Aortic blood pressure in horizontal snakes showed no significant change over a range of body temperatures between 18 and 33 degrees C (mean of measurements on 16 snakes = 42.2 +/− I.98 mmHg), while heart rate increased logarithmically (Q10 approximately 2.5). Blood pressure was stable during heating and cooling between body temperatures of 15 and 30 degrees C, but the pressure was 10--50% higher during heating than during cooling. 2. Head-up tilt usually caused a brief fall in pressure at heart level followed by partial or complete recovery and tachycardia. At the cessation of tilt, there was a characteristic overshoot of the blood pressure followed by readjustment to control (pretilt) levels. Head-down tilt typically increased pressure which then either stabilized or returned toward pretilt levels. Heart rate changes during head-down tilt were not consistent in direction or magnitude. Stabilized pressures at mid-body usually increased following head-up tilt and decreased following head-down tilt, indicating physiological adjustment to posture change. Blood pressure control was evident at body temperatures ranging from 10 to 38 degrees C, but was most effective at the higher and behaviourally preferred temperatures. 3. Propranolol lowered heart rate but did not influence pressure in horizontal snakes. During head-up tilt propranolol eliminated or reduced tachycardia and sometimes reduced the efficacy of pressure compensation for tilt. Phentolamine increased heart rate, lowered blood pressure, and eliminated pressure regulation during tilt. The results suggest that sympathetically mediated reflexes assist central blood pressure regulation in the tiger snake, with vasomotor adjustments having greater importance than changes in heart rate.

Autonomic mechanisms underlying area postrema stimulation-induced cardiovascular responses in rats

1991 ◽  
Vol 261 (1) ◽  
pp. R1-R8 ◽  
Author(s):  
A. V. Ferguson ◽  
P. Smith
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rate Control ◽  
Area Postrema ◽  
Cardiovascular Responses ◽  
Pressure Control ◽  
Blocking Agent ◽  
Adrenergic Blockade ◽  
Neural Pathways ◽  
Heart Rate Control

Experiments were designed to examine the autonomic mechanisms underlying the decreases in blood pressure and heart rate elicited by electrical stimulation in the rat area postrema (AP). Vagotomy was found to significantly reduce the bradycardia observed in response to AP stimulation (control -123.5 +/- 23.5 beats/min; vagotomized -7 +/- 5.4 beats/min; P less than 0.001) but was without significant effect on blood pressure responses. Hexamethonium significantly reduced both heart rate (control -225.5 +/- 11.9 beats/min; hexamethonium -5.5 +/- 2.8 beats/min; P less than 0.001) and depressor (control -35.4 +/- 4.7 mmHg; hexamethonium -6.4 +/- 0.8 mmHg; P less than 0.001) responses to such stimulation, whereas combined alpha- and beta-adrenergic blockade was without effect. The muscarinic blocking agent atropine also abolished both blood pressure (control -22.0 +/- 4.3 mmHg; atropine 2.8 +/- 4.4 mmHg; P less than 0.01) and heart rate (control -187.0 +/- 41.9 beats/min; atropine 8.8 +/- 2.6 beats/min; P less than 0.01) responses to AP stimulation. These data suggest that AP stimulation influences two separate neural pathways eliciting distinct cardiovascular responses. It would appear that activation of one of these pathways results in activation of vagal efferents to the heart and thus bradycardia. A second parallel pathway influenced by AP stimulation apparently elicits depressor response through actions on cholinergic muscarinic receptors.

P3821Resting heart rate in late adolescence and long term risk of cardiomyopathy - A nationwide study of one million Swedish men

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M Lindgren ◽  
J R Robertson ◽  
M A Adiels ◽  
M S Schaufelberger ◽  
M A Aberg ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiorespiratory Fitness ◽  
Myocardial Dysfunction ◽  
Late Adolescence ◽  
Resting Heart Rate ◽  
Drug Induced ◽  
Arterial Blood ◽  
Causal Pathway

Abstract Background/Introduction Elevated resting heart rate (RHR) is a known risk factor for HF. Whether elevated RHR is also associated with cardiomyopathy (CM), a common cause of heart failure in the young, is unknown. Purpose To investigate the association of resting heart rate (RHR) measured in late adolescence with long term risk of various subtypes of CM with special attention to cardiorespiratory fitness (CRF), an important predictor of RHR and myocardial dysfunction. Methods We followed a cohort of Swedish men enrolled for conscription in 1968–2005 (n=1,008,485; mean age=18.3 years) until December 2014. Outcomes of CM were collected from the national inpatient- (IPR), outpatient- (OPR) and cause of death registries and were divided into categories: 1) dilated, 2) hypertrophic, 3) alcohol/drug-induced, and 4) other. Cox proportional hazard models were used to analyze the longitudinal association between RHR and outcomes while adjusting for potential confounders, including body mass index (BMI), arterial blood pressure and cardiorespiratory fitness (CRF). CRF was measured by maximum capacity ergometer testing as part of the enlistment protocol. Results During a mean follow up of 34 years, there were 3500 cases of a first hospitalization for CM (mean age at diagnosis, 50.1 years). Comparing the highest with the lowest quintile of the RHR distribution, we found a positive association between RHR and dilated CM (hazard ratio (HR) = 1.58 [confidence interval (CI) = 1.37–1.82]) after adjustment for BMI, age at conscription, conscription year, test center, and baseline comorbidities (diabetes, hypertension, congenital heart disease). There no significant association with alcohol/drug-induced (HR=1.32 [CI=0.94–1.85]) or other categories of CM. Conclusion Adolescent RHR is associated with future risk CM, independently of blood pressure, BMI and CRF. The association was driven by dilated CM. These findings are suggestive of a causal pathway between elevated heart rate and adverse cardiac remodeling that warrants further investigation. Acknowledgement/Funding The Swedish Heart and Lung Foundation, the Swedish Research Council, the Swedish Council for Health, Working Life and Welfare

scholarly journals Some Aspects of the Physiology and Anatomy of the Cardiovascular System of the Ferret, Mustela Putorius Furo

1979 ◽  
Vol 13 (3) ◽  
pp. 215-220 ◽  
Author(s):  
P. L. R. Andrews ◽  
A. J. Bower ◽  
O. Illman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Vagal Stimulation ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Resting Heart Rate ◽  
Mustela Putorius ◽  
Arterial Blood ◽  
Great Vessels ◽  
Vagal Innervation

Summary The resting heart rate was monitored in SO urethane-anaesthetized (387 ± 54 beats/min) and 4 conscious (341 ± 39 beats/min) ferrets. The arterial blood pressure in the anaesthetized animals was 140/110 ± 35/31 mmHg. The circulatory responses to vagal stimulation, carotid artery occlusion and a variety of humoral agents were examined. The vagal innervation of the heart and of the distribution of the great vessels are described.

scholarly journals Effect of adding dexmedetomidine or remifentanil to thiopental in patients with mood disorder candidate for electroconvulsive therapy

2020 ◽  
pp. 1-6
Author(s):  
Faezeh Heidarbeigi ◽  
Hamidreza Jamilian ◽  
Anita Alaghemand ◽  
Alireza Kamali
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mood Disorders ◽  
Electroconvulsive Therapy ◽  
Recovery Time ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Significant Difference ◽  
The Mean ◽  
Remifentanil Group

Electroconvulsive therapy (ECT) is one of the appropriate treatments for many neuropsychiatric patients, especially those with mood disorders. Short-term complications of ECT include agitation and postictal. In this study, we compared the addition of dexmedetomidine or remifentanil to thiopental as the main anaesthetic used in ECT. In this double-blind randomised clinical trial, 90 patients with mood disorders (candidates for ECT) were divided into two groups based on their therapy: dexmedetomidine or remifentanil. In the first group (DG), patients were slowly injected intravenously with 0.5 μg/kg dexmedetomidine before induction of anesthesia. In the second group (GR), 100 μg of remifentanil was slowly injected intravenously.In addition, we collected demographic information such as respiratory rate, heart pulse rate, seizure time, mean of arterial blood pressure, recovery duration and the oxygen arterial saturation recorded after recovery. Data obtained were analysed by use of statistical software, SPSS-23. The mean age of both groups was approximately 37 years with the majority being men. There was no significant difference between the two groups in terms of age and sex, blood pressure, heart rate, duration of seizures and arterial oxygen saturation before ECT. The mean blood pressure and heart rate in the recovery group were lower in the dexmedetomidine group than in the remifentanil group and the hemodynamics in the dexmedetomidine group were more stable. The recovery time in the dexmedetomidine group was longer than that of the remifentanil group (p = 0.001). Both groups had approximately the same satisfaction and the rate of agitation after ECT was the same. Both remifentanil and dexmedetomidine as adjuvants lead to a decrease in patients' post-ECT hyperdynamic responses. In our study, we demonstrated that the effect of dexmedetomidine is greater than remifentanil. On the other hand, neither dexmedetomidine nor remifentanil had a negative effect on seizure duration, but dexmedetomidine significantly prolonged recovery time, when compared to remifentanil.

Respiratory sinus arrhythmia: time domain characterization using autoregressive moving average analysis

1995 ◽  
Vol 268 (6) ◽  
pp. H2232-H2238 ◽  
Author(s):  
J. K. Triedman ◽  
M. H. Perrott ◽  
R. J. Cohen ◽  
J. P. Saul
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Time Domain ◽  
Rate Control ◽  
Moving Average ◽  
Autoregressive Moving Average ◽  
Heart Rate Control ◽  
Sinus Arrhythmia ◽  
Arterial Blood ◽  
Autonomic Blockade

Fourier-based techniques are mathematically noncausal and are therefore limited in their application to feedback-containing systems, such as the cardiovascular system. In this study, a mathematically causal time domain technique, autoregressive moving average (ARMA) analysis, was used to parameterize the relations of respiration and arterial blood pressure to heart rate in eight humans before and during total cardiac autonomic blockade. Impulse-response curves thus generated showed the relation of respiration to heart rate to be characterized by an immediate increase in heart rate of 9.1 +/- 1.8 beats.min-1.l-1, followed by a transient mild decrease in heart rate to -1.2 +/- 0.5 beats.min-1.l-1 below baseline. The relation of blood pressure to heart rate was characterized by a slower decrease in heart rate of -0.5 +/- 0.1 beats.min-1.mmHg-1, followed by a gradual return to baseline. Both of these relations nearly disappeared after autonomic blockade, indicating autonomic mediation. Maximum values obtained from the respiration to heart rate impulse responses were also well correlated with frequency domain measures of high-frequency "vagal" heart rate control (r = 0.88). ARMA analysis may be useful as a time domain representation of autonomic heart rate control for cardiovascular modeling.

scholarly journals Effect of adding dexmedetomidine or remifentanil to thiopental in patients with mood disorder candidate for electroconvulsive therapy

2020 ◽  
Vol 30 (3) ◽  
Author(s):  
Faezeh Heidarbeigi ◽  
Hamidreza Jamilian ◽  
Anita Alaghemand ◽  
Alireza Kamali
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mood Disorders ◽  
Electroconvulsive Therapy ◽  
Recovery Time ◽  
Arterial Oxygen ◽  
Arterial Blood ◽  
Significant Difference ◽  
The Mean ◽  
Remifentanil Group

Electroconvulsive therapy (ECT) is one of the appropriate treatments for many neuropsychiatric patients, especially those with mood disorders. Short-term complications of ECT include agitation and postictal. In this study, we compared the addition of dexmedetomidine or remifentanil to thiopental as the main anaesthetic used in ECT. In this double-blind randomised clinical trial, 90 patients with mood disorders (candidates for ECT) were divided into two groups based on their therapy: dexmedetomidine or remifentanil. In the first group (DG), patients were slowly injected intravenously with 0.5 μg/kg dexmedetomidine before induction of anesthesia. In the second group (GR), 100 μg of remifentanil was slowly injected intravenously.In addition, we collected demographic information such as respiratory rate, heart pulse rate, seizure time, mean of arterial blood pressure, recovery duration and the oxygen arterial saturation recorded after recovery. Data obtained were analysed by use of statistical software, SPSS-23. The mean age of both groups was approximately 37 years with the majority being men. There was no significant difference between the two groups in terms of age and sex, blood pressure, heart rate, duration of seizures and arterial oxygen saturation before ECT. The mean blood pressure and heart rate in the recovery group were lower in the dexmedetomidine group than in the remifentanil group and the hemodynamics in the dexmedetomidine group were more stable. The recovery time in the dexmedetomidine group was longer than that of the remifentanil group (p = 0.001). Both groups had approximately the same satisfaction and the rate of agitation after ECT was the same. Both remifentanil and dexmedetomidine as adjuvants lead to a decrease in patients' post-ECT hyperdynamic responses. In our study, we demonstrated that the effect of dexmedetomidine is greater than remifentanil. On the other hand, neither dexmedetomidine nor remifentanil had a negative effect on seizure duration, but dexmedetomidine significantly prolonged recovery time, when compared to remifentanil.

scholarly journals The COMPARISON BETWEEN HYPERBARIC BUPIVACAINE PLUS FENTANYL AND HYPERBARIC BUPIVACAINE ALONE IN SPINAL ANESTHESIA FOR CAESAREAN SECTION

2021 ◽  
Vol 71 (3) ◽  
pp. 1033-36
Author(s):  
Fatima Iqbal ◽  
Manzoor Ahmed Faridi ◽  
Aisha Saeed ◽  
Inamullah Shah
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Caesarean Section ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Control Group ◽  
Study Group ◽  
Hyperbaric Bupivacaine ◽  
Arterial Blood ◽  
The Mean

Objective: To compare the result of the combination of hyperbaric bupivacaine plus fentanyl with hyperbaric bupivacaine alone in patients undergoing caesarean section in spinal anaesthesia. Study Design: Comparative, cross-sectional study. Place and Duration of Study: Department of Anesthesia, Fauji Foundation Hospital, Rawalpindi Pakistan, from Dec 2017 to Jun 2018. Methodology: After consulting the institutional ethical review committees a total of 60 females between ages 18-40 years were enrolled for caesarean section delivery. They were divided into two groups. The study group (n=30) received a subarachnoid injection of 0.5% hyperbaric bupivacaine (10mg) 2ml with 25ug of fentanyl 0.5ml and control group (n=30) was injected 0.5% hyperbaric bupivacaine 12.5mg (2.5 ml) only. Pain experienced during the procedure was assessed by using 10-point visual analogue scoring method. The mean duration of analgesia, mean arterial blood pressure and heart rate after surgery were compared between two groups. Results: The mean duration of analgesia was 206.5/min ± 6.4 in the study group and it was 163.6min ± 7.2 in the control group (p=0.001). Mean arterial BP after surgery was 92.3mmHg ± 3.8 in the study group and 88.7mmHg ± 4.1 in the control group (p=0.001). The mean heart rate recorded after surgery was 75.2/min ± 5.2 in the study group and it was 70.4/min ± 6.1 in the control group (p=0.001). Conclusions: The mean duration of analgesia was significantly longer in the study group when compared with the control group with better mean arterial blood pressure and heart rate response after Caesarean section.

Aestivation of the African Lungfish Protopterus Aethiopicus: Cardiovascular and Respiratory Functions

1974 ◽  
Vol 61 (1) ◽  
pp. 111-128 ◽  
Author(s):  
R. G. DELANEY ◽  
S. LAHIRI ◽  
A. P. FISHMAN
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Respiratory Function ◽  
Control Range ◽  
Arterial Blood ◽  
Arterial Ph ◽  
Sensory Disturbances ◽  
The Mean ◽  
African Lungfish

The present study was undertaken to elicit the temporal sequence of changes in cardiovascular and respiratory function during aestivation. Twelve lungfish (2-6 kg) equipped with ECG electrodes, arterial and buccal cannulae, were studied while aestivating in mud or in artificial cloth-bag nests. The periods of observation ranged from 0.5 to 9.5 months. The mean arterial blood pressure gradually decreased from control values of 20-28 mm Hg to a range of 14-18 mmHg during the first 30 days of aestivation, whereas the heart rate dropped more gradually (22-30 beats/min to 11-16 beats/min in 6o days). Ventilatory frequency increased 2- to 5-fold during the first 30 days of encystment and then returned to the control range (2-10 h) within 45 days. The arterial PCOCO2 increased from control values of 25-30 mm Hg to 45-70 mmHg; arterial pH decreased concomitantly from 7.55-7.60 to 7.40-7.26 after the cocoon was formed. The arterial POO2 increased from the control range of 25-40 to 50-58 mmHg during the first 10 days and then returned to the control range. Therefore, the sequential cardiopulmonary changes during the onset of aestivation are gradual and do not parallel the decline in oxygen consumption. Aestivating lungfish also respond promptly to sensory disturbances and thus do not appear to be in a deep torpor. Aestivation is pictured as a state of dormancy, gradual in onset, and the consequence of a complicated physiological interplay.

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