Heart Rate In Dogs Research Articles

Validation of heart rate spot-check protocol to measure circadian variation and heart rate in healthy dogs and dogs with atrial fibrillation

IntroductionAlternatives for out-of-clinic heart rate (HR) measurement are required to optimise the management of atrial fibrillation (AF) in dogs. Additionally, the presence of circadian variation (CV) in HR in pet dogs remains unknown.We aimed to identify the number and duration of spot-checks required for an accurate estimation of 24-hour HR in canine AF. Circadian variation in HR was examined in healthy dogs and dogs with AF, and spot-check-derived HR was compared with a CV-derived gold standard. Materials and methodsAmbulatory electrocardiogram data from healthy dogs and dogs with AF were retrospectively analysed. Heart rate was calculated from the entire recording and pre-defined periods (spot-checks) of one hour to 30 and 60 s in duration. Circadian variation in HR was determined by cosinor analysis. Bias and limits of agreement of means and median HR with mesor HR were determined by correlation and Bland–Altman analysis. ResultsCircadian variation in HR was identified not only in 18/22 healthy dogs and 14/21 AF dogs but only on ambulatory electrocardiogram recordings.Four-hourly spot-checks provided the most accurate estimate of mesor HR in healthy dogs (bias of the median over 30 s 7.70, limits of agreement 7.48), whereas, in dogs with AF, four, six and eight-hourly spot-checks provided reliable estimates of mesor HR (bias within −1.29 and −29.5). ConclusionsFour, six and eight-hourly HR spot-checks can estimate 24-hourly HR in dogs with AF. There was CV in HR in most healthy pet dogs and dogs with AF. Spot-check protocols cannot identify CV in HR.

Heart Rate Changes Before, During, and After Treadmill Walking Exercise in Normal Dogs.

In dogs, changes in heart rate (HR) can reflect conditioning, fear, anticipation, and pain; however, these are not routinely assessed in veterinary rehabilitation patients. Knowing the expected HR changes during rehabilitation exercises can guide protocols and can optimize post-operative therapy. The primary objectives of the study were to assess HR in dogs undergoing treadmill exercise (TE) during the walk and to compare the three collection techniques of HR, namely, auscultation, a HR monitor (HR MONITOR), and a Holter monitor (HOLTER). We hypothesized that the HR would increase by 20% during TE, that HR taken after TE would not be the same as the HR during TE, and that all methods of measurement would have good agreement. HR was recorded in all methods simultaneously, in eight adult healthy large breed dogs during rest (REST), immediately before TE (PRE), during TE (WALK), and 15 and 60 s after TE (POST-15, POST-60). Statistical analyses included Spearman and Pearson correlations, Bland-Altman analyses, and a repeated measures ANOVA with Sidak's post-hoc test (significant at value of p < 0.05). Increased HR was reflected in TE during WALK, and elevations in HR during WALK were not reflected in POST timepoints. Auscultation was also not possible during WALK. Significant moderate-to-strong correlations existed among all monitoring options at each of the timepoints (rho range = 0.5–0.9, p < 0.05). There were no correlations between peak HR and age or weight. The main limitation of this study is that only healthy and large breed dogs were used. Both monitors captured the increase in HR during exercise and could guide TE regimens to minimize patient risk of injury and to maximize training effectiveness.

Retrospective study of allometric relationship between heart rate, electrocardiographic parameters and bodyweight in dogs

ABSTRACT The allometric relationship between bodyweight (BW) and heart rate (HR) has been described as inversely proportional in domestic species, but that has been refuted. The relationship between HR and electrocardiographic variables is described in literature. However, studies about the variation and influence of factors on the hemodynamic and electrocardiographic parameters in dogs are not abundant. As the metabolic rate is defined as the production and dissipation of heat by the body surface area (BSA) in m², it is essential to define that relationship. A retrospective study was conducted to analyze the correlation between HR, ECG parameters and BW in dogs. One thousand electrocardiographic tracings were analyzed in addition to the ECG parameters and clinical data such as gender, age and bodyweight. The determination of BSA was performed as follows: BSA (m2) = (10.1 x bodyweight 0.67) X 10-4. When the unified groups were analyzed, there was a negative but weak correlation (r= -0.14, P&lt; 0.0001) between bodyweight and HR. There were differences between weight groups regarding electrocardiographic variables. There is no allometric relationship between BW and HR in dogs. Weight was associated with changes in ECG variables.

Long-term intermittent high-amplitude subcutaneous nerve stimulation reduces sympathetic tone in ambulatory dogs

Reducing sympathetic efferent outflow from the stellate ganglia (SG) may be antiarrhythmic. The purpose of this study was to test the hypothesis that chronic thoracic subcutaneous nerve stimulation (ScNS) could reduce SG nerve activity (SGNA) and control paroxysmal atrial tachycardia (PAT). Thoracic ScNS was performed in 8 dogs while SGNA, vagal nerve activity (VNA), and subcutaneous nerve activity (ScNA) were monitored. An additional 3 dogs were used for sham stimulation as controls. Xinshu ScNS and left lateral thoracic nerve ScNS reduced heart rate (HR). Xinshu ScNS at 3.5 mA for 2 weeks reduced mean average SGNA from 5.32 μV (95% confidence interval [CI] 3.89-6.75) at baseline to 3.24 μV (95% CI 2.16-4.31; P = .015) and mean HR from 89 bpm (95% CI 80-98) at baseline to 83 bpm (95% CI 76-90; P = .007). Bilateral SG showed regions of decreased tyrosine hydroxylase staining with increased terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive nuclei in 18.47% (95% CI 9.68-46.62) of all ganglion cells, indicating cell death. Spontaneous PAT episodes were reduced from 9.83 per day (95% CI 5.77-13.89) in controls to 3.00 per day (95% CI 0.11-5.89) after ScNS (P = .027). Left lateral thoracic nerve ScNS also led to significant bilateral SG neuronal death and significantly reduced average SGNA and HR in dogs. ScNS at 2 different sites in the thorax led to SG cell death, reduced SGNA, and suppressed PAT in ambulatory dogs.

Scaling Relationships Among Heart Rate, Electrocardiography Parameters, and Body Weight

Although heart rate (HR) is one of the most important clinical parameters determined via physical examinations, little information is available on the normal HR in dogs, which may be related to the high variability of body weight (BW) in this species. HR is determined by the discharge rate of the sinus node, which is dependent on the autonomic nervous system and the release of catecholamines. The allometric relationship between BW and HR in different species has been described as inversely proportional; however, this relationship has been refuted. Certain authors have reported that the relationship between HR and BW in dogs is based on temperament as well as sympathetic autonomic stimulation of the sinus node in small breeds compared with large breeds. The aim of this study was to analyze the effects of weight, sex, age and temperament on the HR, heart rate variability and serum catecholamine (epinephrine and norepinephrine) levels in dogs. We evaluated 48 adult dogs of both sexes and various breeds and ages and divided the dogs into 5 BW groups: <5kg (n = 8), 5-10kg (n = 10), 10-25kg (n = 10), 25-45kg (n = 10), and >45kg (n = 10). The measured parameters were HR, breath rate (BR) and body temperature. We also performed an ambulatory electrocardiogram and electrocardiography (ECG) test for 24 hours (Holter monitor) and determined the serum levels of the catecholamines epinephrine and norepinephrine. We observed correlations between HR and sex; differences among the weight groups with respect to ECG variables and epinephrine levels; and differences among the temperament categories for certain clinical parameters, such as HR and BR. Age affected the R wave amplitude, and an allometric relationship was not observed between HR and BW in the dogs. Our results indicated that weight was associated with variations in the ECG variables; age and sex were associated with variations in HR; and temperament had a significant influence on the HR and BR of the dogs.

Music's Effect on Dogs' Heart Rates

The goal of this project was to determine the effect of different types of music on a dog's heart rate. Six different dogs were tested in their own homes. Each experiment was performed in a quiet room with the dog’s owner present along with the two scientists performing the testing. Five different types of music were used in the experiment. Using a stethoscope, we measured the resting heart rate prior to testing and again immediately following the test. A five-minute break was taken between each test, and two trials were completed for each test conducted. The result was a statistically significant difference in heart rate for rock and rap music (increase) and for jazz music (decrease). A caveat to this study was the relatively small number of dogs tested (six); therefore, future research with a larger sample size should be conducted to confirm these results. This information could help calm dogs in potentially stressful situations, such as the veterinary office or when traveling.

Comparative study of heart rate obtained by oscillometric device and multiparameter monitor in female dogs during ovariohysterectomy

Monitoring of vital signs of animals is essential during anesthesia procedures and surgery being the heart rate (HR) one of the parameters evaluated and it is necessary to use reliable methods. Aiming to evaluate the accuracy of two methods of measuring HR in dogs, there was a comparative study of two devices used for this purpose, these being an oscillometric measuring equipment (Petmap®) and a heart monitor multiparameter (Cardiovet). 71 healthy young bitches were evaluated under inhalation anesthesia during surgery elective ovariohysterectomy with isoflurane. From the beginning of the surgery, which lasted 30 minutes on average, the values of heart rate were measured by both devices every 10 minutes, for a total of three measurements per animal. We calculated the average of the three measured values and used the average for descriptive and evaluation by the Student t test statistic. The results for the oscillometric machine and heart monitor were respectively 106.35 and 108.56 ± 16:15 ± 20.28 bpm, not statistically different (p&gt; 0.05). This shows the similarity of the accuracy of the two devices in measuring the heart rate of dogs, indicating that the choice of equipment can be charged to the veterinarian, according to your need in the medical and surgical clinic, since the oscillometric device measures well as blood pressure and heart monitor additionally provides electrocardiographic data.

Lack of correlation between canine heart rate and body size in veterinary clinical practice

An association between heart rate (HR) and bodyweight has been reported in dogs and it is common belief that small breeds of dog exhibit higher HR than large breeds. The first aim of this study was to test the null hypothesis that, in veterinary clinical practice, bodyweight does not affect HR measured in healthy dogs. A second objective of this investigation was to assess whether other variables, such as gender, breed morphology, age and demeanour, may have a significant effect on dog's HR measured in a clinical setting. The investigation was performed via two different studies: a retrospective analysis performed on 243 electrocardiogram recordings and a prospective study based on 153 standardised clinical examinations. The two separate studies did not show any significant correlation between HR and bodyweight (P=0.5705 and P=0.4682, respectively). Subject's breed morphology and gender did not appear to affect HR measured under these circumstances. However, dogs under the age of one year seem to have significantly higher HRs than older dogs (P < 0.05). Finally, subject's demeanour was also found to have a significant influence on HR; lower values were recorded in relaxed dogs, and higher rates were documented in excited, nervous dogs (P < 0.05). Normal HR could be erroneously interpreted as bradycardia or tachycardia if bodyweight was to be considered a determinant factor. Instead, HR in healthy dogs undergoing routine clinical examination is related to their demeanour or age, if younger than 12 months, but does not appear to be related to bodyweight.

Central nervous system effects of corticotropin releasing factor in the dog

Corticotropin releasing factor (CRF) given intracerebroventricularly (i.c.v.) increases mean arterial pressure (MAP) and heart rate (HR), while CRF given intravenously decreases MAP and increases HR. CRF given i.c.v. elevates plasma concentrations of vasopressin and catecholamines. Ganglionic blockade with chlorisondamine prevents CRF-induced increases in MAP; the vasopressin antagonist, [1-deaminopenicillamine,2-(O-methyl)tyrosine]-vasopressin does not alter CRF-induced increases in MAP. In contrast to CRF, angiotensin II (A-II) given i.c.v. increases MAP but decreases HR. In conclusion: (1) CRF elevation of MAP and HR in dogs is dependent on an intact sympathetic nervous system, and (2) CRF and A-II have different CNS effects on cardiovascular function.

Differential effects of person in the dog and in the human

People have marked effects on dog's heart rate, with great individual variations for different persons. Apparently people to which the dog is attached have the greatest effect upon heart rate. Replications of the animal experiments using the psychotherapist and two other people revealed no effects upon the heart rate of a schizophrenic human. In the human the effects of people are probably best demonstrated in connection with verbal communication.

Effects of ataractic drugs on the blood-pressure and heart-rate of dogs.

THE assessment of the haemodynamic effects of ataractic drugs, such as the phenothiazine derivatives, has, in the past, always been carried out in anaesthetized or curarized animals1–5. Since the action of the ataractic drug may modify, or be modified by, the effect of the anaesthetic or neuro muscular blocking agent, it has been difficult to assess whether the haemodynamic changes observed have been due to the ataractic drug itself. It is therefore of interest to record a method of assessment which has been used for studying the effects produced by several phenothiazine derivatives in normal conscious dogs, and which has been shown to produce results which do not entirely agree with those obtained in anaesthetized animals.