Factors Related to the Dive Reflex in Harbor Seals: Respiration, Immersion Bradycardia, and Lability of the Heart Rate

1974 ◽  
Vol 52 (2) ◽  
pp. 248-258 ◽  
Author(s):  
Robert W. Dykes
Keyword(s):  
Heart Rate ◽  
Individual Differences ◽  
Time Course ◽  
Breathing Pattern ◽  
Mean Amplitude ◽  
Harbor Seals ◽  
Normal Heart ◽  
Normal Heart Rate ◽  
The Mean ◽  
Mean Heart Rate

The normal heart rate of young breathing harbor seals, 130.1 beats/min (S.E.M. = 22, n = 33), decreases by 50% during periods of spontaneous apnea in air and by 69% during 2 min of forced apnea in air. Apneic bradycardia develops five times more slowly than bradycardia observed during immersion. During forced apnea the heart rate drops to 31% of the value observed during periods of breathing in 200 s while during immersion the heart rate drops to this value only after 20 s. Since the bradycardia during apnea has a slower time course, apnea alone cannot account for the bradycardia observed during immersion.In quietly resting seals, the apneustic breathing pattern consisted of periods of breathing (duration of 10–115 s) interrupted by apneic pauses (duration of 19–104 s). During the breathing periods successive breaths tended to be smaller so that at the end of a breathing period the mean amplitude of a respiratory movement was only 57% of the mean amplitude of the first inspiration. Tracheostomy altered the breathing pattern and lowered the mean heart rate during breathing to 43% of the rate observed in intact animals. Under controlled conditions immersion bradycardia was highly reproducible and showed no signs of conditioning to the experimental regime. Data from 56 immersions on three animals illustrated minor individual differences in the time course of the immersion bradycardia and provided the basis for an estimate of the average time course of immersion bradycardia in young harbor seals.

Evaluation of Normal Heart Rate in Early Pregnancy Corresponding to Gestational Age between Six to Eight Weeks

Med Phoenix ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 34-37
Author(s):  
Akhilesh Kumar Jha ◽  
Bikranta Rimal ◽  
Tarannum Khatun
Keyword(s):  
Heart Rate ◽  
Early Pregnancy ◽  
Well Being ◽  
Clinical Decision ◽  
First Trimester ◽  
Normal Heart ◽  
Normal Heart Rate ◽  
First Trimester Of Pregnancy ◽  
Singleton Pregnancies

Background: Ultrasonography is the reliable and safe way for the evaluation of pregnancy. Heart rate can be detected more confidently from the Ultrasonography. Heart rate is an important parameter for the evaluation of early pregnancy. The purpose of this study was to evaluate the normal heart rate in embryos/fetuses between 6 and 8 weeks of gestation.Method: In our region people are poor and most of them do not know the benefit of regular follow up examination during pregnancy. So most of pregnant women come to our centre at late stage of pregnancy. The number of pregnancy cases is good in our centre but the number of early pregnancy cases coming to regular follow up examination is low. Thus the study was conducted in 51 normal singleton pregnancies undergoing routine ultrasound examination during the first trimester of pregnancy. The duration of study was 6 weeks.Result: Out of 51 singleton pregnancies, 20 cases (39.2%) heart rate were between 131-150 beat per minute and 25 cases (49.0 %) heart rate were between 151-170 beat per minute. However 4 cases (7.8%) were between 110-120 beat per minute and 2 cases (3.9%) were more than 171 beat per minute. There were zero cases above the 180 beat per minute.Conclusion: The result of this study will help to evaluate abnormal and normal fetal heart rate so that early clinical decision whether to continue the pregnancy or terminate it can be taken, as Ultrasonography is only the method used in screening fetal well being in most of the region of our country.Med Phoenix Vol.2(1) July 2017, 34-37

Heart rate responses and plasma cortisol concentrations in ewes: comparison between cervical and laparoscopic intrauterine insemination and their associated handling procedures

1998 ◽  
Vol 66 (2) ◽  
pp. 383-387 ◽  
Author(s):  
M. Khalid ◽  
W. Haresign ◽  
D. G. Bradley
Keyword(s):  
Heart Rate ◽  
Stress Responses ◽  
Plasma Cortisol ◽  
Intrauterine Insemination ◽  
Management Practice ◽  
Treatment Groups ◽  
Cortisol Responses ◽  
The Mean ◽  
Pre Treatment ◽  
Mean Heart Rate

AbstractThis study consisted of two experiments. In experiment 1, stress responses of sheep which were restrained either in a laparoscopy cradle or a roll-over cradle were compared. The results of this experiment indicated that restraint in roll-over cradle is less (P < 0·05) stressful than that in a laparoscopy cradle when assessed in terms of the elevation and duration of both the mean heart rate and plasma cortisol responses. Experiment 2 compared the stress responses of sheep subjected to restraint in a laparoscopy cradle, restraint in a laparoscopy cradle with intrauterine artificial insemination (AI) by laparoscopy, minimal restraint with cervical AI or restraint in a roll-over cradle plus foot-trimming. All treatments resulted in significant elevations in both heart rate and plasma cortisol concentrations (F < 0·001). The peak heart rate was significantly (P < 0·05) higher in ewes subjected to cervical AI than in those subjected to intrauterine insemination, with other treatments intermediate. The peak cortisol response did not differ among different treatments. The duration over which both the mean heart rate and -plasma cortisol concentrations remained significantly elevated above pre-treatment concentrations did not differ among treatment groups. The results of this study suggest that while restraint using a laparoscopy cradle is more stressful than that using a rollover cradle, the stress inflicted by intrauterine insemination by laparoscopy itself is no greater than that due to restraint using the laparoscopy cradle alone, cervical AI or the management practice offoot-trimming using a rollover cradle.

scholarly journals Low-Frequency Oscillations (<0.3 Hz) in the Electromyographic (EMG) Activity of the Human Trapezius Muscle During Sleep

2002 ◽  
Vol 88 (3) ◽  
pp. 1177-1184 ◽  
Author(s):  
R. H. Westgaard ◽  
P. Bonato ◽  
K. A. Holte
Keyword(s):  
Heart Rate ◽  
Muscle Activity ◽  
Activity Pattern ◽  
Sudden Change ◽  
Mean Amplitude ◽  
Activity Level ◽  
Emg Activity ◽  
Similar Frequency ◽  
Emg Signal ◽  
The Mean

The surface electromyographic (EMG) signal from right and left trapezius muscles and the heart rate were recorded over 24 h in 27 healthy female subjects. The root-mean-square (RMS) value of the surface EMG signals and the heartbeat interval time series were calculated with a time resolution of 0.2 s. The EMG activity during sleep showed long periods with stable mean amplitude, modulated by rhythmic components in the frequency range 0.05–0.2 Hz. The ratio between the amplitude of the oscillatory components and the mean amplitude of the EMG signal was approximately constant over the range within which the phenomenon was observed, corresponding to a peak-to-peak oscillatory amplitude of ∼10% of the mean amplitude. The duration of the periods with stable mean amplitude ranged from a few minutes to ∼1 h, usually interrupted by a sudden change in the activity level or by cessation of the muscle activity. Right and left trapezius muscles presented the same pattern of FM. In supplementary experiments, rhythmic muscle activity pattern was also demonstrated in the upper extremity muscles of deltoid, biceps, and forearm flexor muscles. There was no apparent association between the rhythmic components in the muscle activity pattern and the heart rate variability. To our knowledge, this is the first time that the above-described pattern of EMG activity during sleep is documented. On reanalysis of earlier recorded trapezius motor unit firing pattern in experiments on awake subjects in a situation with mental stress, low-FM of firing with similar frequency content was detected. Possible sources of rhythmic excitation of trapezius motoneurons include slow-wave cortical oscillations represented in descending cortico-spinal pathways, and/or activation by monoaminergic pathways originating in the brain stem reticular formation. The analysis of muscle activity patterns may provide an important new tool to study neural mechanisms in human sleep.

scholarly journals Accurate Estimation of Heart and Respiration Rates Based on an Optical Fiber Sensor Using Adaptive Regulations and Statistical Classifications Spectrum Analysis

2021 ◽  
Vol 3 ◽  
Author(s):  
Rongjian Zhao ◽  
Lidong Du ◽  
Zhan Zhao ◽  
Xianxiang Chen ◽  
Jie Sun ◽  
...  
Keyword(s):  
Heart Rate ◽  
Individual Differences ◽  
Optical Fiber ◽  
Confidence Intervals ◽  
Respiration Rate ◽  
Spectrum Analysis ◽  
Optical Fiber Sensor ◽  
Fiber Sensor ◽  
Respiration Rates ◽  
The Mean

The aim of this work is to present a method for accurately estimating heart and respiration rates under different actual conditions based on a mattress which was integrated with an optical fiber sensor. During the estimation, a ballistocardiogram (BCG) signal, which was obtained from the optical fiber sensor, was used for extracting the heart rate and the respiration rate. However, due to the detrimental effects of the differential detector, self-interference, and variation of installation status of the sensor, the ballistocardiogram (BCG) signal was difficult to detect. In order to resolve the potential concerns of individual differences and body interferences, adaptive regulations and statistical classifications spectrum analysis were used in this paper. Experiments were carried out to quantify heart and respiration rates of healthy volunteers under different breathing and posture conditions. From the experimental results, it could be concluded that (1) the heart rates of 40–150 beats per minute (bpm) and respiration rates of 10–20 breaths per minute (bpm) were measured for individual differences; (2) for the same individuals under four different posture contacts, the mean errors of heart rates were separately 1.60 ± 0.98 bpm, 1.94 ± 0.83 bpm, 1.24 ± 0.59 bpm, and 1.06 ± 0.62 bpm, in contrast, the mean errors of the polar beat device were 1.09 ± 0.96 bpm, 1.44 ± 0.99 bpm, and 1.78 ± 0.94 bpm. Furthermore, the experimental results were validated by conventional counterparts which used skin-contacting electrodes as their measurements. It was reported that the heart rate was 0.26 ± 2.80 bpm in 95% confidence intervals (± 1.96SD) in comparison with Philips sure-signs VM6 medical monitor, and the respiration rate was 0.41 ± 1.49 bpm in 95% confidence intervals (± 1.96SD) in comparison with ECG-derived respiratory (EDR) measurements for respiration rates. It was indicated that the developed system using adaptive regulations and statistical classifications spectrum analysis performed better and could easily be used under complex environments.

Response time of cardiac mitochondrial oxygen consumption to heart rate steps

1991 ◽  
Vol 260 (2) ◽  
pp. H613-H625 ◽  
Author(s):  
J. H. Van Beek ◽  
N. Westerhof
Keyword(s):  
Heart Rate ◽  
Response Time ◽  
Time Course ◽  
Mean Transit Time ◽  
Impulse Response Function ◽  
Heart Tissue ◽  
Experimental Information ◽  
O2 Consumption ◽  
Mean Response Time ◽  
The Mean

We investigated the time course of cardiac mitochondrial O2 consumption following steps in heart rate in 16 isolated rabbit hearts perfused with Tyrode solution. The time course was characterized by the mean response time, i.e., the first statistical moment (mean time) of the impulse response function. Like the mean transit time for an indicator, it provides an important characteristic of the response time course. The venous O2 content transients during steps in heart rate were measured and corrected for O2 diffusion and vascular transport using a mathematical model with experimental information derived from O2 washout following steps in arterial O2 concentration or perfusion flow. We deduce from these washout experiments that the effective O2 solubility in heart tissue is 86 +/- 13% (mean +/- SE) of solubility in water. The measured venous mean response time following a step in heart rate at 37 degrees C was 17.6 +/- 1.1 s. The mean response time of cardiac mitochondrial O2 consumption to changes in heart rate after correction for O2 transport was 7.7 +/- 0.7 s.

scholarly journals A Neurophysiological Study of Semantic Processing in Parkinson’s Disease

2016 ◽  
Vol 23 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Anthony J. Angwin ◽  
Nadeeka N.W. Dissanayaka ◽  
Alison Moorcroft ◽  
Katie L. McMahon ◽  
Peter A. Silburn ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Semantic Processing ◽  
Time Course ◽  
Event Related Potentials ◽  
Mean Amplitude ◽  
Repetition Effects ◽  
Related Potentials ◽  
The Mean ◽  
Written Word

AbstractObjectives: Cognitive-linguistic impairments in Parkinson’s disease (PD) have been well documented; however, few studies have explored the neurophysiological underpinnings of semantic deficits in PD. This study investigated semantic function in PD using event-related potentials. Methods: Eighteen people with PD and 18 healthy controls performed a semantic judgement task on written word pairs that were either congruent or incongruent. Results: The mean amplitude of the N400 for new incongruent word pairs was similar for both groups, however the onset latency was delayed in the PD group. Further analysis of the data revealed that both groups demonstrated attenuation of the N400 for repeated incongruent trials, as well as attenuation of the P600 component for repeated congruent trials. Conclusions: The presence of N400 congruity and N400 repetition effects in the PD group suggests that semantic processing is generally intact, but with a slower time course as evidenced by the delayed N400. Additional research will be required to determine whether N400 and P600 repetition effects are sensitive to further cognitive decline in PD. (JINS, 2017, 23, 78–89)

Effect of ouabain on pressor responsiveness in normal man

1994 ◽  
Vol 267 (5) ◽  
pp. E642-E647
Author(s):  
G. B. Pidgeon ◽  
A. M. Richards ◽  
M. G. Nicholls ◽  
R. R. Bailey ◽  
K. L. Lynn ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Volunteers ◽  
Plasma Levels ◽  
Plasma Renin ◽  
Ang Ii ◽  
Short Term ◽  
Vasoactive Hormones ◽  
Normal Man ◽  
The Mean ◽  
Mean Heart Rate

To assess the effects of ouabain on pressor and vasoactive hormone responsiveness, 10 healthy volunteers were pretreated with ouabain (0.5 mg i.v. 42 and 18 h before study) or placebo before pressor challenge with angiotensin II (ANG II; 2, 4, and 8 ng.kg-1.min-1 for 30 min/dose) and norepinephrine (NE; 5, 15, and 45 ng.kg-1.min-1 for 15 min/dose). There were no differences at baseline between the two study days regarding mean arterial pressure (MAP) or heart rate. Baseline pulse pressure, however, was significantly greater after ouabain (47 +/- 3 vs. 41 +/- 1 mmHg; P < 0.05). The mean maximum increments in MAP during ANG II and NE infusions were 17.5 +/- 1.1 and 10.5 +/- 1.3 (SE) mmHg, respectively, after ouabain and 19.2 +/- 1.3 and 10.4 +/- 1.5 mmHg after placebo (not significant). The mean heart rate was lower during both infusion periods on the ouabain study day compared with control (P < 0.05). Baseline plasma levels of ANG II, aldosterone, plasma renin activity, atrial and brain natriuretic peptide, guanosine 3',5'-cyclic monophosphate, NE, and epinephrine and achieved levels during the two infusions were similar on the two study days. We conclude that short-term ouabain administration does not alter pressor responsiveness or plasma levels of vasoactive hormones in healthy volunteers.

scholarly journals SARS-CoV-2 infection in an infant with severe dilated cardiomyopathy

2020 ◽  
pp. 1-3
Author(s):  
Aslak Widerøe Kristoffersen ◽  
Per Kristian Knudsen ◽  
Thomas Møller
Keyword(s):  
Heart Rate ◽  
Dilated Cardiomyopathy ◽  
Fluid Balance ◽  
Cardiac Disease ◽  
Gastrointestinal Symptoms ◽  
Close Monitoring ◽  
Disease Course ◽  
Normal Heart ◽  
The Past ◽  
Normal Heart Rate

Abstract A four- and a half-month-old girl with severe dilated cardiomyopathy due to neonatal enterovirus myocarditis, treated with diuretics and milrinone for the past 4 months, was infected with SARS-CoV-2. The disease course was characterised by high fever and gastrointestinal symptoms. Cardiac function, as measured by echocardiography, remained stable. The treatment focused on maintaining a normal heart rate and a stable fluid balance. In children with severe underlying cardiac disease, even a mild SARS-CoV-2 infection can require close monitoring and compound treatment.

scholarly journals Etorphine-halothane anaesthesia in two five-year-old African elephants (Loxodonta africana) : clinical communication

1999 ◽  
Vol 70 (4) ◽  
Author(s):  
G.F. Stegmann
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Pressure ◽  
Loxodonta Africana ◽  
African Elephants ◽  
Clinical Communication ◽  
Dental Surgery ◽  
Blood Pressures ◽  
The Mean ◽  
Mean Heart Rate

Anaesthesia of 2 five-year-old femaleAfrican elephants (Loxodonta africana) was required for dental surgery. The animals were each premedicated with 120 mg of azaperone 60 min before transportation to the hospital. Before offloading, 1 mg etorphine was administered intramuscularly (i.m.) to each elephant to facilitate walking them to the equine induction / recovery room. For induction, 2 mg etorphine was administered i.m. to each animal. Induction was complete within 6 min. Surgical anaesthesia was induced with halothane-in-oxygen after intubation of the trunk. During surgery the mean heart rate was 61 and 45 beats / min respectively. Systolic blood pressures increased to 27.5 and 25.6 kPa respectively, and were treated with intravenous azaperone. Blood pressure decreased thereafter to a mean systolic pressure of 18.1 and 19.8 kPa, respectively. Rectal temperature was 35.6 and 33.9 oC at the onset of surgery, and decreased to 35.3 and 33.5 oC, respectively, at the end of anaesthesia. Etorphine anaesthesia was reversed with 5mg diprenorphine at the completion of 90 min of surgery.

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