Short-term effects of Whole-Body Vibration on clinical, cardiac, and ambulatory electrocardiographic (Holter) parameters of healthy younger and older adult male non-athletic crossbreed dogs / [Efeitos agudos da Vibração de Corpo Inteiro nos parêmetros clínico, cardíaco e eletrocardiografia ambulatorial (Holter) em cães jovens e idosos sem raça definida, hígidos e não atletas]

This study investigated the effects of WBV in clinical, cardiac, and ambulatory electrocardiographic (Holter) parameters of healthy young and aged male non-athletic dogs. Fourteen dogs were divided into two groups of seven animals: Group I (GI) - young dogs (12.0 and 84.0 months old); Group II (GII) - aged dogs (above 84.0 months old). Dogs were submitted to a single session of WBV (frequencies of 30 and 50 Hz), for 15-min. Variations were identified in the thickness of the interventricular septum and thickness of the left ventricle-free wall values: GI < GII at 5-min before the session. The diameter of the left atrium values showed a difference: GI < GII at 5-min before and 1-min after the session; and a decrease in GII between 5-min before and 1 min after the WBV. Several ambulatory electrocardiography (Holter) parameters demonstrated significant differences between both groups and time-points. A single session of WBV at frequencies of 30 and 50 Hz during 15-min by using a vibrating platform that delivered a vortex wave circulation did not induce significant changes in clinical, cardiac, and ambulatory electrocardiographic (Holter) parameters in healthy young and aged dogs.

O estudo teve como objetivo avaliar os efeitos agudos da vibração de corpo inteiro (VCI) nos parâmetros clínicos, cardíacos e eletrocardiográficos ambulatoriais (Holter) de cães jovens e adultos hígidos sem raça definida e não atletas. Quatorze cães foram divididos em dois grupos de sete cães, de acordo com a idade: Grupo I (GI) - entre 12,0 e 84,0 meses; Grupo II (GII) - acima de 84,0 meses. Os cães foram submetidos à única sessão de VCI com frequências de 30 e 50 Hz, durante 15 minutos. Foram identificadas variações significativas na espessura do septo interventricular e da espessura da parede do ventrículo esquerdo: GI

Short-term heart rate variability analysis in healthy dogs of different ages

Background: The modulation of heart rate by autonomic nervous system may be evaluated by the heart rate variability(HRV), which illustrates the fluctuations between RR intervals. To evaluate this analysis, the intervals between 2 QRScomplexes are measured. In general, high HRV values are expected in healthy individuals; otherwise, low values are indicative of organism dysfunction. Studies conducted in healthy humans show that HRV suffers reduction with ageing andthat there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiacautonomic behavior in healthy dogs in different age groups through short-term HRV analysis.Materials, Methods & Results: A total of 87 healthy dogs were studied. HRV was analyzed in time and frequency domain,using Holter and heart rate monitor. It was observed that puppies (below one year old) presented a lower parasympatheticpredominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other2 groups and on frequency domain (LF, HF and LF/HF) compared to the adult animals group (between 1 and 7-year-old),which presented higher HRV values when compared to the other groups. Elderly dogs (over 8-year-old) exhibited a naturaltendency to decrease cardiac parasympathetic HRV indexes.Discussion: The use of the HRV method as a prognostic index and as an arrhythmogenic marker for various canine heartdiseases presents interesting perspectives. However, before it may be employed for these purposes, a better understandingshould be established regarding the physiological behavior of autonomic cardiac modulation in different age groups toserve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter...

Short-term heart rate variability analysis in healthy dogs of different ages

Background: The modulation of heart rate by autonomic nervous system may be evaluated by the heart rate variability(HRV), which illustrates the fluctuations between RR intervals. To evaluate this analysis, the intervals between 2 QRScomplexes are measured. In general, high HRV values are expected in healthy individuals; otherwise, low values are indicative of organism dysfunction. Studies conducted in healthy humans show that HRV suffers reduction with ageing andthat there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiacautonomic behavior in healthy dogs in different age groups through short-term HRV analysis.Materials, Methods & Results: A total of 87 healthy dogs were studied. HRV was analyzed in time and frequency domain,using Holter and heart rate monitor. It was observed that puppies (below one year old) presented a lower parasympatheticpredominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other2 groups and on frequency domain (LF, HF and LF/HF) compared to the adult animals group (between 1 and 7-year-old),which presented higher HRV values when compared to the other groups. Elderly dogs (over 8-year-old) exhibited a naturaltendency to decrease cardiac parasympathetic HRV indexes.Discussion: The use of the HRV method as a prognostic index and as an arrhythmogenic marker for various canine heartdiseases presents interesting perspectives. However, before it may be employed for these purposes, a better understandingshould be established regarding the physiological behavior of autonomic cardiac modulation in different age groups toserve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter...(AU)

Monitorização eletrocardiográfica contínua em cães portadores de degeneração mixomatosa valvular mitral / Continuous electrocardiographic monitoring in dogs with mitral valve mixomatic degeneration

A Degeneração Mixomatosa Valvar (DMV) representa um processo degenerativo crônico dos folhetos atrioventriculares, impedindo sua perfeita coaptação. Consequentemente podem ocorrem a ativação de mecanismos compensatórios congestivos e o início de uma importante sintomatologia. Em muitos casos esta enfermidade correlaciona-se com a ocorrência de importantes arritmias. Neste trabalho descrevem-se sob os aspectos clínicos e arritmogênicos, por meio do método Holter, de dois casos de DMV em pacientes de diferentes classificações funcional, segundo os critérios do Colégio Americano de Medicina Veterinária Interna, um em estágio B1 e outro em estágio D crônico. Os achados apontam que as arritmias cardíacas são eventos recorrentes em pacientes portadores de Degeneração Mixomatosa Valvar Mitral (DMVM), e que ainda em estágios iniciais, sem remodelamento, esta pode estar presente em baixa densidade; bem como nos estágios avançados, o índice de remodelamento cardíaco pode estar diretamente correlacionado à incidência de arritmias, comumente descritas na literatura, ou outras mais graves não relatadas, como a disfunção sinusal.

Myxomatous Valve Degeneration (DMV) represents a chronic degenerative process of the atrioventricular leaflets, preventing their perfect coaptation. Consequently, the activation of congestive compensatory mechanisms and the beginning of an important symptomatology may occur. In many cases this disease is correlated with the occurrence of important arrhythmias. In this work, two clinical cases of DMV in patients with different functional classification according to the American College of Internal Veterinary Medicine criteria are described under clinical and arrhythmogenic aspects, one in stage B1 and the other in chronic stage D. The findings indicate that cardiac arrhythmias are recurrent events in patients with Myxomatous Mitral Valve Degeneration (DMVM), and that even in the early stages without remodeling, they may be present in low density; as well as in the advanced stages, the cardiac remodeling index it may be directly correlated with the incidence of arrhythmias commonly described in the literature, or other more serious ones not reported, such as sinus dysfunction.

Monitorização eletrocardiográfica contínua em cães portadores de degeneração mixomatosa valvular mitral / Continuous electrocardiographic monitoring in dogs with mitral valve mixomatic degeneration

A Degeneração Mixomatosa Valvar (DMV) representa um processo degenerativo crônico dos folhetos atrioventriculares, impedindo sua perfeita coaptação. Consequentemente podem ocorrem a ativação de mecanismos compensatórios congestivos e o início de uma importante sintomatologia. Em muitos casos esta enfermidade correlaciona-se com a ocorrência de importantes arritmias. Neste trabalho descrevem-se sob os aspectos clínicos e arritmogênicos, por meio do método Holter, de dois casos de DMV em pacientes de diferentes classificações funcional, segundo os critérios do Colégio Americano de Medicina Veterinária Interna, um em estágio B1 e outro em estágio D crônico. Os achados apontam que as arritmias cardíacas são eventos recorrentes em pacientes portadores de Degeneração Mixomatosa Valvar Mitral (DMVM), e que ainda em estágios iniciais, sem remodelamento, esta pode estar presente em baixa densidade; bem como nos estágios avançados, o índice de remodelamento cardíaco pode estar diretamente correlacionado à incidência de arritmias, comumente descritas na literatura, ou outras mais graves não relatadas, como a disfunção sinusal.(AU)

Myxomatous Valve Degeneration (DMV) represents a chronic degenerative process of the atrioventricular leaflets, preventing their perfect coaptation. Consequently, the activation of congestive compensatory mechanisms and the beginning of an important symptomatology may occur. In many cases this disease is correlated with the occurrence of important arrhythmias. In this work, two clinical cases of DMV in patients with different functional classification according to the American College of Internal Veterinary Medicine criteria are described under clinical and arrhythmogenic aspects, one in stage B1 and the other in chronic stage D. The findings indicate that cardiac arrhythmias are recurrent events in patients with Myxomatous Mitral Valve Degeneration (DMVM), and that even in the early stages without remodeling, they may be present in low density; as well as in the advanced stages, the cardiac remodeling index it may be directly correlated with the incidence of arrhythmias commonly described in the literature, or other more serious ones not reported, such as sinus dysfunction.(AU)

Minimum dose of levothyroxine restored the autonomic balance on a Dalmatian female dog with primary hypothyroidism

Background: Hypothyroidism is an endocrine disease that leads to a reduction in the hormones thyroxine (T3) and triiodothyronine (T4), which therapy with levothyroxine restores the clinical signs related to the metabolic rate. Due to the influence of thyroid hormones on the heart, which is under the constant influence of the autonomic nervous system (ANS), dogs with hypothyroidism can develop bradycardia, arrhythmia, and dysautonomia. Heart rate variability (HRV) assesses autonomic modulation by the Holter method, which is scarce in dogs. We aimed to report the cardiac and autonomic effects of the primary hypothyroidism untreated and treated with levothyroxine in a canine case by Holter monitoring. Case: A 7-year-old female Dalmatian, weighing 36 kg, was referred for clinical evaluation due to apathy, weight gain, low hair quality, and lethargy. On physical examination, alopecic lesions on the hind limbs and tail, as well as bradycardia with a heart rate (HR) of 40-50 beats per minute (bpm) were observed, in addition to a 3/6 mitral murmur and 2/6 tricuspid murmur. Given the suspicion of thyroid gland disorder, the blood hormonal measurement revealed an increase in thyroidstimulating hormone (TSH; 0.65 ng/mL) and a decrease in free T4 (0.11 ng/mL) and total T4 (0.44 ng/mL), confirming primary hypothyroidism. Therapy was started with a minimum dose of levothyroxine (0.913 mg, every 12 h), which clinical signs were restored in 5 months of treatment, with weight loss, hair growth, and active behavior. To assess the impact of untreated and treated hypothyroidism on the patient’s ANS, a Holter monitoring exam was performed for 24 h before and after therapy. Before treatment, the average HR was 75 bpm, and the HR2.0s), 1st-degree atrioventricular blocks (AVB), six...

Minimum dose of levothyroxine restored the autonomic balance on a Dalmatian female dog with primary hypothyroidism

Background: Hypothyroidism is an endocrine disease that leads to a reduction in the hormones thyroxine (T3) and triiodothyronine (T4), which therapy with levothyroxine restores the clinical signs related to the metabolic rate. Due to the influence of thyroid hormones on the heart, which is under the constant influence of the autonomic nervous system (ANS), dogs with hypothyroidism can develop bradycardia, arrhythmia, and dysautonomia. Heart rate variability (HRV) assesses autonomic modulation by the Holter method, which is scarce in dogs. We aimed to report the cardiac and autonomic effects of the primary hypothyroidism untreated and treated with levothyroxine in a canine case by Holter monitoring. Case: A 7-year-old female Dalmatian, weighing 36 kg, was referred for clinical evaluation due to apathy, weight gain, low hair quality, and lethargy. On physical examination, alopecic lesions on the hind limbs and tail, as well as bradycardia with a heart rate (HR) of 40-50 beats per minute (bpm) were observed, in addition to a 3/6 mitral murmur and 2/6 tricuspid murmur. Given the suspicion of thyroid gland disorder, the blood hormonal measurement revealed an increase in thyroidstimulating hormone (TSH; 0.65 ng/mL) and a decrease in free T4 (0.11 ng/mL) and total T4 (0.44 ng/mL), confirming primary hypothyroidism. Therapy was started with a minimum dose of levothyroxine (0.913 mg, every 12 h), which clinical signs were restored in 5 months of treatment, with weight loss, hair growth, and active behavior. To assess the impact of untreated and treated hypothyroidism on the patients ANS, a Holter monitoring exam was performed for 24 h before and after therapy. Before treatment, the average HR was 75 bpm, and the HR<50 bpm occurred during 05 h 20 min 36 s. Still, 320 pause events (>2.0s), 1st-degree atrioventricular blocks (AVB), six...(AU)

Avaliação da variabilidade da frequencia cardíaca (VFC) em cão da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito (CAVD) / Evaluation of heart rate variability (HRV) in a Boxer dog with arrhythmogenic right ventricle cardiomyopathy (ARVC)

Background: Boxer dog cardiomyopathy was initially described by Neil Harpster in 1983 and has received different names. However, several recent studies demonstrated a similarity to the human arrhythmogenic right ventricular cardiomyopathy (ARVC), which led to the name Boxer ARVC. This hereditary disease seems to be linked to a mutation in the gene that codifies the cardiac ryanodine receptor. This mutation leads to an alteration of the calcium cycle in the heart. The analysis of the heart rate variability is an important predictive factor for diagnosing this disease. Therefore, this study aims to report a case of a Boxer ARVC providing electrocardiographic data and heart rate variability.Case: A 11 year-old male Boxer dog, weighting 29.65 kg, was submitted to a heart check-up due to sudden occurrence of fatigue and syncope. At the clinical examination, heart auscultation did not revealed sounds or arrhythmias. The electrocardiogram results presented tachycardia and a regular rhythm with ventricular premature complexes (VPC´s). Ecodopplercargiogram was performed and values were within normal standards. Thus, a dynamic monitoring of 24 h was performed using a Holter monitor. This analysis demonstrated tachycardia in the sinus rhythm, type I second degree sinoatrial block, normal PR interval and normal length of QRS complexes. In addition, severe ventricular ectopy was identified in the following forms: isolated, paired, and nonsustained ventricular tachycardia. The heart rate variability analysis resulted in mean values of 213 ms (SNDD), 132 ms (SDANN), 211ms (rMSSD) and 33.46% (pNN50). Based on these data, Boxer ARVC is the probable diagnosis. However, a ventricular myocardial biopsy necessary to confirm the disease was not performed due to the inherent risk of the procedure. Treatment was performed with sotalol and a commercial feed specially designed for dogs with for cardiac diseases.[...](AU)

Avaliação da variabilidade da frequencia cardíaca (VFC) em cão da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito (CAVD) / Evaluation of heart rate variability (HRV) in a Boxer dog with arrhythmogenic right ventricle cardiomyopathy (ARVC)

Background: Boxer dog cardiomyopathy was initially described by Neil Harpster in 1983 and has received different names. However, several recent studies demonstrated a similarity to the human arrhythmogenic right ventricular cardiomyopathy (ARVC), which led to the name Boxer ARVC. This hereditary disease seems to be linked to a mutation in the gene that codifies the cardiac ryanodine receptor. This mutation leads to an alteration of the calcium cycle in the heart. The analysis of the heart rate variability is an important predictive factor for diagnosing this disease. Therefore, this study aims to report a case of a Boxer ARVC providing electrocardiographic data and heart rate variability.Case: A 11 year-old male Boxer dog, weighting 29.65 kg, was submitted to a heart check-up due to sudden occurrence of fatigue and syncope. At the clinical examination, heart auscultation did not revealed sounds or arrhythmias. The electrocardiogram results presented tachycardia and a regular rhythm with ventricular premature complexes (VPC´s). Ecodopplercargiogram was performed and values were within normal standards. Thus, a dynamic monitoring of 24 h was performed using a Holter monitor. This analysis demonstrated tachycardia in the sinus rhythm, type I second degree sinoatrial block, normal PR interval and normal length of QRS complexes. In addition, severe ventricular ectopy was identified in the following forms: isolated, paired, and nonsustained ventricular tachycardia. The heart rate variability analysis resulted in mean values of 213 ms (SNDD), 132 ms (SDANN), 211ms (rMSSD) and 33.46% (pNN50). Based on these data, Boxer ARVC is the probable diagnosis. However, a ventricular myocardial biopsy necessary to confirm the disease was not performed due to the inherent risk of the procedure. Treatment was performed with sotalol and a commercial feed specially designed for dogs with for cardiac diseases.[...]

Time domain heart rate variability in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy / Variabilidade da frequência cardíaca no domínio do tempo em cães da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito

The aim of the present study was to assess heart rate variability (HRV) in Boxer dogs affected by arrhythmogenic right ventricular cardiomyopathy (ARVC). Fourteen Boxer dogs classified as affected and 28 classified as unaffected were included in a prospective case-control study. Dogs underwent 24-hour ambulatory ECG and were classified as affected (>1,000 VPCs/24 hours) or unaffected (<20 VPCs/24 hours) by ARVC based on the number of ventricular arrhythmias. HRV was assessed using 24-h Holter ECG monitoring; the studied parameters were SDNN, SDANN, SDNNIDX, rMSSD and pNN50. Data were submitted to logarithmic transformation and HRV parameters were compared between groups and correlated according to the disease status, number and severity of ventricular arrhythmias using Student’s t test, linear regression and Spearman’s test. There was no interaction between the HRV parameters and the number and severity of ventricular arrhythmias. SDNNlog (2.35±0.14 vs. 2.46±0.12, P=0.01), SDNNIDXlog (2.18±0.14 vs. 2.24±0.10, P=0.002) and pNN50log (1.47±0.19 vs. 1.64±0.13, P=0.002) were significantly lower in the affected group compared with the unaffected. According to this study, HRV are different in a population of Boxers dogs affected by ARVC compared to a population of unaffected dogs, and these differences are not consequences of low cardiac output caused by ventricular arrhythmias since animals that had higher number and complexity of arrhythmias were not those who had lower values of HRV.

O objetivo do presente estudo foi avaliar a variabilidade da frequência cardíaca (VFC) em cães da raça Boxer acometidos pela cardiomiopatia arritmogênica do ventrículo direito (CAVD). Para isso, foram incluídos, em estudo prospectivo caso-controle, 14 cães classificados como acometidos pela CAVD e 28 classificados como não acometidos. Os cães foram submetidos à eletrocardiografia ambulatorial de 24 horas e então classificados como acometidos (quando apresentaram mais de 1.000 complexos ventriculares prematuros em 24 horas) ou não acometidos (quando apresentaram menos de 20 complexos ventriculares prematuros em 24 horas) pela CAVD, com base no número de arritmias ventriculares. A VFC foi avaliada mediante monitoramento Holter de 24 horas. Os parâmetros estudados foram SDNN, SDANN, SDNNIDX, rMSSD e pNN50. Os dados foram submetidos à transformação logarítmica e os parâmetros da VFC foram comparados e correlacionados de acordo com a presença ou não da doença, número e severidade das arritmias pelo teste t de Student, regressão linear e teste de Spearman. Não houve interação entre as variáveis da VFC e o número e a severidade das arritmias ventriculares. Porém, as variáveis SDNNlog (2,35±0,14 vs. 2,46±0,12, P=0,01), SDNNIDXlog (2,18±0,14 vs. 2,24±0,10, P=0.002) e pNN50log (1,47±0,19 vs. 1,64±0,13, P=0,002) foram significativamente menores no grupo de animais acometidos pela doença. De acordo com os resultados do presente estudo, a VFC é menor nos Boxers acometidos pela CAVD em relação aos cães não acometidos, e essa diferença não pode ser atribuída ao baixo débito cardíaco, supostamente causado pelas arritmias ventriculares, uma vez que os animais que apresentaram maior número e complexidade das arritmias não foram os que apresentaram os menores valores da VFC.

Time domain heart rate variability in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy / Variabilidade da frequência cardíaca no domínio do tempo em cães da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito

The aim of the present study was to assess heart rate variability (HRV) in Boxer dogs affected by arrhythmogenic right ventricular cardiomyopathy (ARVC). Fourteen Boxer dogs classified as affected and 28 classified as unaffected were included in a prospective case-control study. Dogs underwent 24-hour ambulatory ECG and were classified as affected (>1,000 VPCs/24 hours) or unaffected (<20 VPCs/24 hours) by ARVC based on the number of ventricular arrhythmias. HRV was assessed using 24-h Holter ECG monitoring; the studied parameters were SDNN, SDANN, SDNNIDX, rMSSD and pNN50. Data were submitted to logarithmic transformation and HRV parameters were compared between groups and correlated according to the disease status, number and severity of ventricular arrhythmias using Students t test, linear regression and Spearmans test. There was no interaction between the HRV parameters and the number and severity of ventricular arrhythmias. SDNNlog (2.35±0.14 vs. 2.46±0.12, P=0.01), SDNNIDXlog (2.18±0.14 vs. 2.24±0.10, P=0.002) and pNN50log (1.47±0.19 vs. 1.64±0.13, P=0.002) were significantly lower in the affected group compared with the unaffected. According to this study, HRV are different in a population of Boxers dogs affected by ARVC compared to a population of unaffected dogs, and these differences are not consequences of low cardiac output caused by ventricular arrhythmias since animals that had higher number and complexity of arrhythmias were not those who had lower values of HRV.(AU)

O objetivo do presente estudo foi avaliar a variabilidade da frequência cardíaca (VFC) em cães da raça Boxer acometidos pela cardiomiopatia arritmogênica do ventrículo direito (CAVD). Para isso, foram incluídos, em estudo prospectivo caso-controle, 14 cães classificados como acometidos pela CAVD e 28 classificados como não acometidos. Os cães foram submetidos à eletrocardiografia ambulatorial de 24 horas e então classificados como acometidos (quando apresentaram mais de 1.000 complexos ventriculares prematuros em 24 horas) ou não acometidos (quando apresentaram menos de 20 complexos ventriculares prematuros em 24 horas) pela CAVD, com base no número de arritmias ventriculares. A VFC foi avaliada mediante monitoramento Holter de 24 horas. Os parâmetros estudados foram SDNN, SDANN, SDNNIDX, rMSSD e pNN50. Os dados foram submetidos à transformação logarítmica e os parâmetros da VFC foram comparados e correlacionados de acordo com a presença ou não da doença, número e severidade das arritmias pelo teste t de Student, regressão linear e teste de Spearman. Não houve interação entre as variáveis da VFC e o número e a severidade das arritmias ventriculares. Porém, as variáveis SDNNlog (2,35±0,14 vs. 2,46±0,12, P=0,01), SDNNIDXlog (2,18±0,14 vs. 2,24±0,10, P=0.002) e pNN50log (1,47±0,19 vs. 1,64±0,13, P=0,002) foram significativamente menores no grupo de animais acometidos pela doença. De acordo com os resultados do presente estudo, a VFC é menor nos Boxers acometidos pela CAVD em relação aos cães não acometidos, e essa diferença não pode ser atribuída ao baixo débito cardíaco, supostamente causado pelas arritmias ventriculares, uma vez que os animais que apresentaram maior número e complexidade das arritmias não foram os que apresentaram os menores valores da VFC.(AU)

Holter monitoring (24-h electrocardiography) of Holstein calves

Background: Twenty-four h electrocardiographic monitoring is a noninvasive method of assessing cardiac rhythm. Holter monitoring in farm animals can help assessing heart rate variability and its relationship with stress and production. Several authors have reviewed the normal cardiac rhythm of bovines, but there is little information on heart rhythm in calves. The goal of this research is to elucidate which cardiac rhythms may be considered physiological in Holstein calves, from 3 to 6 months old. Materials, Methods & Results: Twenty-four h ambulatory electrocardiography (Holter monitoring) was performed in 10 male Holstein calves, with ages ranging from 3 to 6 months old. The animals came from private farms in São Paulo state and were housed in a semi-open stall during the study. The animals had their hair clipped from the third to the fifth intercostal spaces on both sides of the chest, from the sternal region to the glenohumeral joint, and seven electrodes were positioned in a diagonal configuration. Decoding of the recordings was performed using specialized software and in order to minimize digital mistakes, all of the beats marked as ectopic by the software were manually revised by the authors. Mean heart rate was 83.2 ± 11.06 beats per min (bpm), maximum heart rate was 147.1 ± 11.05 bpm, and minimum heart rate was 53.7 ± 7.45 bpm. In 90% of the calves, normal sinus [...](AU)

Holter monitoring (24-h electrocardiography) of Holstein calves

Background: Twenty-four h electrocardiographic monitoring is a noninvasive method of assessing cardiac rhythm. Holter monitoring in farm animals can help assessing heart rate variability and its relationship with stress and production. Several authors have reviewed the normal cardiac rhythm of bovines, but there is little information on heart rhythm in calves. The goal of this research is to elucidate which cardiac rhythms may be considered physiological in Holstein calves, from 3 to 6 months old. Materials, Methods & Results: Twenty-four h ambulatory electrocardiography (Holter monitoring) was performed in 10 male Holstein calves, with ages ranging from 3 to 6 months old. The animals came from private farms in São Paulo state and were housed in a semi-open stall during the study. The animals had their hair clipped from the third to the fifth intercostal spaces on both sides of the chest, from the sternal region to the glenohumeral joint, and seven electrodes were positioned in a diagonal configuration. Decoding of the recordings was performed using specialized software and in order to minimize digital mistakes, all of the beats marked as ectopic by the software were manually revised by the authors. Mean heart rate was 83.2 ± 11.06 beats per min (bpm), maximum heart rate was 147.1 ± 11.05 bpm, and minimum heart rate was 53.7 ± 7.45 bpm. In 90% of the calves, normal sinus [...]

Valor prognóstico da variabilidade da frequência cardíaca e da eletrocardiografia ambulatorial em cães Boxer com cardiomiopatia arritmogênica do ventrículo direito / Prognostic value of heart rate variability and Holter monitoring in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma importante causa de morte súbita em cães da raça Boxer. A validação de fatores prognósticos para essa doença auxiliaria na detecção de animais mais gravemente afetados e sua exclusão dos programas de reprodução. O objetivo deste estudo foi avaliar o valor prognóstico da presença de manifestações clínicas, dos índices de variabilidade de frequência cardíaca (VFC) e das arritmias supraventriculares ou ventriculares registradas à monitorização eletrocardiográfica com Holter na sobrevida de cães Boxer em diferentes estágios da CAVD. Essas variáveis foram analisadas, de forma prospectiva, em 69 cães Boxer, divididos em cinco grupos: cães Boxer controle (grupo CB, <50 VPC/24 horas, n=28), cães Boxer suspeitos (grupo SB, 50 a 300 VPC/24 horas, n=8), cães Boxer com CAVD (grupo ARVC, >300 VPC/24 horas, n=19), cães Boxer com CAVD e disfunção sistólica sem insuficiência cardíaca congestiva (grupo SDB sem ICC, n=6) e com ICC (grupo SDB com ICC, n=8). A análise estatística compreendeu teste ANOVA, correlação de Pearson e análise de riscos proporcionais de Cox. Comparando-se com o grupo CB, não foi encontrada diminuição nos índices de VFC nos grupos SB, ARVC ou SDB sem ICC; por outro lado, o grupo SDB com ICC apresentou diminuição desses índices. Não houve relação entre os índices de VFC e a morte de origem cardíaca; porém, a presença de síncopes com ou sem sinais clínicos de ICC e o número de episódios de taquicardia ventricular (TV) correlacionaram-se com a sobrevida dos animais. Estes resultados permitem concluir que a presença de sinais clínicos de ICC, a presença de síncopes e o número de TV ao Holter apresentam valor prognóstico de sobrevida em cães Boxer com CAVD.(AU)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in Boxer dogs. Validation of prognostic factors for this disease could help in detecting more severely affected animals and their exclusion from breeding programs. The aims of this study were to evaluate the prognostic significance of presence of symptoms, heart rate variability (HRV) indices and ventricular or supraventricular arrhythmias recorded by Holter monitoring on survival of Boxer dogs with ARVC at different stages. Symptoms, arrhythmias registered on Holter and five HRV indices were prospectively analyzed in 69 client-owned Boxer dogs divided into five groups: control Boxer dogs (CB group, <50 VPC/24 hours, n=28), suspicious Boxers (SB group, 50 to 300 VPC/24 hours, n=8), Boxers with ARVC (ARVC group, >300 VPC/24 hours, n=19), Boxers with ARVC and systolic dysfunction without congestive heart failure (SDB without CHF group, n=6) and with CHF (SDB with CHF group, n=8). Statistical analyses consisted of an ANOVA test, Pearson correlation and Cox's proportional hazards regression. Compared to the CB group, no decrease in HRV indices was found in SB, ARVCB or SDB without CHF groups; otherwise, SDB with CHF group had impaired indices. No relation was found between HRV indices and cardiac-related death, but the presence of syncopes with or without clinical signs of heart failure and number of ventricular tachycardia (VT), were correlated with survival. These results allow us to conclude that the presence of symptoms of heart failure, presence of syncopes and number of VT on Holter examination seem to have prognostic value in Boxer ARVC.(AU)

Valor prognóstico da variabilidade da frequência cardíaca e da eletrocardiografia ambulatorial em cães Boxer com cardiomiopatia arritmogênica do ventrículo direito / Prognostic value of heart rate variability and Holter monitoring in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma importante causa de morte súbita em cães da raça Boxer. A validação de fatores prognósticos para essa doença auxiliaria na detecção de animais mais gravemente afetados e sua exclusão dos programas de reprodução. O objetivo deste estudo foi avaliar o valor prognóstico da presença de manifestações clínicas, dos índices de variabilidade de frequência cardíaca (VFC) e das arritmias supraventriculares ou ventriculares registradas à monitorização eletrocardiográfica com Holter na sobrevida de cães Boxer em diferentes estágios da CAVD. Essas variáveis foram analisadas, de forma prospectiva, em 69 cães Boxer, divididos em cinco grupos: cães Boxer controle (grupo CB, <50 VPC/24 horas, n=28), cães Boxer suspeitos (grupo SB, 50 a 300 VPC/24 horas, n=8), cães Boxer com CAVD (grupo ARVC, >300 VPC/24 horas, n=19), cães Boxer com CAVD e disfunção sistólica sem insuficiência cardíaca congestiva (grupo SDB sem ICC, n=6) e com ICC (grupo SDB com ICC, n=8). A análise estatística compreendeu teste ANOVA, correlação de Pearson e análise de riscos proporcionais de Cox. Comparando-se com o grupo CB, não foi encontrada diminuição nos índices de VFC nos grupos SB, ARVC ou SDB sem ICC; por outro lado, o grupo SDB com ICC apresentou diminuição desses índices. Não houve relação entre os índices de VFC e a morte de origem cardíaca; porém, a presença de síncopes com ou sem sinais clínicos de ICC e o número de episódios de taquicardia ventricular (TV) correlacionaram-se com a sobrevida dos animais. Estes resultados permitem concluir que a presença de sinais clínicos de ICC, a presença de síncopes e o número de TV ao Holter apresentam valor prognóstico de sobrevida em cães Boxer com CAVD.(AU)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in Boxer dogs. Validation of prognostic factors for this disease could help in detecting more severely affected animals and their exclusion from breeding programs. The aims of this study were to evaluate the prognostic significance of presence of symptoms, heart rate variability (HRV) indices and ventricular or supraventricular arrhythmias recorded by Holter monitoring on survival of Boxer dogs with ARVC at different stages. Symptoms, arrhythmias registered on Holter and five HRV indices were prospectively analyzed in 69 client-owned Boxer dogs divided into five groups: control Boxer dogs (CB group, <50 VPC/24 hours, n=28), suspicious Boxers (SB group, 50 to 300 VPC/24 hours, n=8), Boxers with ARVC (ARVC group, >300 VPC/24 hours, n=19), Boxers with ARVC and systolic dysfunction without congestive heart failure (SDB without CHF group, n=6) and with CHF (SDB with CHF group, n=8). Statistical analyses consisted of an ANOVA test, Pearson correlation and Cox's proportional hazards regression. Compared to the CB group, no decrease in HRV indices was found in SB, ARVCB or SDB without CHF groups; otherwise, SDB with CHF group had impaired indices. No relation was found between HRV indices and cardiac-related death, but the presence of syncopes with or without clinical signs of heart failure and number of ventricular tachycardia (VT), were correlated with survival. These results allow us to conclude that the presence of symptoms of heart failure, presence of syncopes and number of VT on Holter examination seem to have prognostic value in Boxer ARVC.(AU)

Anatomical, cardiovascular, and blood gas parameters in dogs with brachycephalic syndrome

Background: Brachycephalic syndrome is characterized by increased airflow resistance in upper airways due to the combinations of anatomical deformities such as stenotic nares, elongated soft palate, everted laryngeal saccules, and tracheal hypoplasia. There is little information in recent literature about assessment of anatomical, cardiovascular, and blood gases parameters of these animals at early stages of the syndrome. The purpose of this study was to characterize and to compare anatomical, cardiovascular, and blood gases parameters in young brachycephalic or dolichocephalic and mesocephalic dogs. Materials, Methods & Results: Twenty brachycephalic dogs (BG) and 20 dolichocephalic and mesocephalic dogs (CG), aged up to 5 years, were included in the study. Anatomical abnormalities, systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressure were recorded. Blood gas analysis and complete blood counts (CBC) were analyzed. Doppler echocardiography, electrocardiography, ambulatory electrocardiography, and thoracic and cervical radiographs were evaluated. The diameter of the nares in BG was lower when compared to CG (0.23 ± 0.08 versus 0.56 ± 0.05 cm, P 0.001). The Sa O2 was lower (P 0.001) and MAP was higher in BG (P = 0.05). All brachycephalic dogs had sinus arrhythmia (SA), and 15 (75 %) of these showed SA higher than 20% variation between adjacent [...](AU)

Anatomical, cardiovascular, and blood gas parameters in dogs with brachycephalic syndrome

Background: Brachycephalic syndrome is characterized by increased airflow resistance in upper airways due to the combinations of anatomical deformities such as stenotic nares, elongated soft palate, everted laryngeal saccules, and tracheal hypoplasia. There is little information in recent literature about assessment of anatomical, cardiovascular, and blood gases parameters of these animals at early stages of the syndrome. The purpose of this study was to characterize and to compare anatomical, cardiovascular, and blood gases parameters in young brachycephalic or dolichocephalic and mesocephalic dogs. Materials, Methods & Results: Twenty brachycephalic dogs (BG) and 20 dolichocephalic and mesocephalic dogs (CG), aged up to 5 years, were included in the study. Anatomical abnormalities, systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressure were recorded. Blood gas analysis and complete blood counts (CBC) were analyzed. Doppler echocardiography, electrocardiography, ambulatory electrocardiography, and thoracic and cervical radiographs were evaluated. The diameter of the nares in BG was lower when compared to CG (0.23 ± 0.08 versus 0.56 ± 0.05 cm, P 0.001). The Sa O2 was lower (P 0.001) and MAP was higher in BG (P = 0.05). All brachycephalic dogs had sinus arrhythmia (SA), and 15 (75 %) of these showed SA higher than 20% variation between adjacent [...]

Influência da altitude sobre parâmetros eletrocardiográficos, obtidos por meio do uso do "Holter" em cavalos de enduro em diferentes níveis de condicionamento físico / Influence of altitude on electrocardiographic parameters by means of the Holter system utilization in endurance horses in different levels of physical conditioning

O presente trabalho teve por objetivo o estudo da influência da altitude sobre os parâmetros eletrocardiográficos obtidos por meio do uso do Holter em 40 cavalos das raças Árabe e Cruza Árabe, em diferentes níveis de condicionamento físico, realizando treinamento em trilhas de 15 km de extensão com velocidade média de 15km/h e variando entre o nível do mar até 1700m de altitude. O monitoramento eletrocardiográfico foi obtido por eletrocardiografia padrão em repouso antes do exercício e por eletrocardiografia dinâmica, com o uso do Holter, durante o exercício e na recuperação pós-exercício. Os animais apresentaram ritmo sinusal com período médio gravado para taquicardia sinusal (32%) e bradicardia sinusal (14%). Entre as arritmias observadas estão o bloqueio atrioventricular de primeiro grau (20%) e o bloqueio atrioventricular de segundo grau (5%). As arritmias ectópicas supraventriculares foram observadas em dois animais e somente um animal apresentou arritmia ventricular. O número de assistolias foi maior em animais menos condicionados. As frequências cardíacas médias e máximas sofreram efeito da altitude com valores maiores em altitude elevada.(AU)

The aim of this paper was to study the influence of altitude on electrocardiographic parameters by means of the Holter system in 40 Arabian and Arabian crossbred horses, at different levels of physical conditioning, during training in trails of 15 km extension with mean speed of 15 km/h, and altitude varying from sea level to 1700m high. The electrocardiographic monitoring was obtained by standard electrocardiography at rest before exercise, and by dynamic electrocardiography with the Holter system applied during exercise and in post-exercise recovery. The animals presented sinusal rhythm, with a mean registered period for sinusal tachycardia of 32%, and 14% for sinusal bradycardia. Among the arrhythmias there was first-degree atrioventricular block (20%) and second-degree atrioventricular block (5%). Supraventricular ectopic arrhythmias were observed in two horses and only one showed ventricular arrhythmia. The number of asystoles was greater in less conditioned horses. Mean and maximal heart rates were influenced by altitude, with higher values in higher altitudes.(AU)

Determinação da pressão venosa cefálica e jugular e em cães saudáveis / Determination of cephalic and jugular venous pressure in healthy dogs

Central venous pressure (CVP) is an important parameter for monitoring in various clinical and experimental situations. In veterinary patients, depending on the clinical or surgical approach, the temperament of the animal and your clinical status, the measurement of PVC cannot be performed properly. Thus, the measurement of the jugular venous pressure (JVP) and/or cephalic (CfVP) may be an method for estimating the systemic venous pressure in animals. Thus, this study aimed to determine and to correlate the measures of the JVP and PVCf obtained of healthy dogs. For this 10 healthy dogs were used. All animals were subjected to physical, hematologic, electrocardiographic and echocardiographic evaluation. Any kind of sedation or anesthesia was used. The results showed JVP average values between 4 and -2 cm of water and CfPV between 2 and 16 cm of water. No correlation between JVP and the CfPV was found.

A pressão venosa central (PVC) é um importante parâmetro de monitorização nas mais diversas situações clínicas e experimentais. Em pacientes veterinários, dependendo da abordagem clínica ou cirúrgica, do temperamento do animal e de seu estado clínico, a aferição da PVC não pode ser realizada adequadamente. Assim, é possível que a medição das pressões venosas jugular (PVJ) e/ou cefálica (PVCf) possa ser capaz de estimar a pressão venosa central em animais. Desse modo, este estudo objetivou determinar e correlacionar as medidas da PVJ e da PVCf obtidas de cães saudáveis. Para isso foram utilizados 10 cães saudáveis. Todos os animais foram submetidos a avaliação física, hematológica, eletrocardiográfica e ecocardiográfica. Não foi utilizado qualquer tipo de sedação ou anestesia. Os resultados demonstraram valores médios da PVJ entre -2 e 4 cm de H2O e da PVCf entre 2 a 16 cm de H2O. Não foi observada correlação entre a PVJ e a PVCf.

Determinação da pressão venosa cefálica e jugular e em cães saudáveis / Determination of cephalic and jugular venous pressure in healthy dogs

Central venous pressure (CVP) is an important parameter for monitoring in various clinical and experimental situations. In veterinary patients, depending on the clinical or surgical approach, the temperament of the animal and your clinical status, the measurement of PVC cannot be performed properly. Thus, the measurement of the jugular venous pressure (JVP) and/or cephalic (CfVP) may be an method for estimating the systemic venous pressure in animals. Thus, this study aimed to determine and to correlate the measures of the JVP and PVCf obtained of healthy dogs. For this 10 healthy dogs were used. All animals were subjected to physical, hematologic, electrocardiographic and echocardiographic evaluation. Any kind of sedation or anesthesia was used. The results showed JVP average values between 4 and -2 cm of water and CfPV between 2 and 16 cm of water. No correlation between JVP and the CfPV was found.(AU)

A pressão venosa central (PVC) é um importante parâmetro de monitorização nas mais diversas situações clínicas e experimentais. Em pacientes veterinários, dependendo da abordagem clínica ou cirúrgica, do temperamento do animal e de seu estado clínico, a aferição da PVC não pode ser realizada adequadamente. Assim, é possível que a medição das pressões venosas jugular (PVJ) e/ou cefálica (PVCf) possa ser capaz de estimar a pressão venosa central em animais. Desse modo, este estudo objetivou determinar e correlacionar as medidas da PVJ e da PVCf obtidas de cães saudáveis. Para isso foram utilizados 10 cães saudáveis. Todos os animais foram submetidos a avaliação física, hematológica, eletrocardiográfica e ecocardiográfica. Não foi utilizado qualquer tipo de sedação ou anestesia. Os resultados demonstraram valores médios da PVJ entre -2 e 4 cm de H2O e da PVCf entre 2 a 16 cm de H2O. Não foi observada correlação entre a PVJ e a PVCf.(AU)