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)

Prognostic value of coupling interval, prematurity index and heart rate variability in Boxer dogs

ABSTRACT: Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC) can experience sudden cardiac death regardless of presence/absence of clinical signs. The aims of this retrospective study were two-fold: 1) to investigate the coupling interval (CI) and prematurity index (PI) of ventricular arrhythmias (VA), and the heart rate variability (HRV) in Boxers, and 2) to evaluate their impact on overall survival time. The first 24-hour Holter 36 client-owned Boxer dogs meeting inclusion/exclusion criteria were evaluated for the number, morphology, site of origin, complexity, CI and PI, of ventricular premature complexes (VPCs), and time domain HRV. The effect on survival was assessed, considering the presence/absence of ventricular tachycardia (VT), and syncope. All-cause mortality was considered as the end-point, with median survival times being obtained by Kaplan-Meier analyses and compared by log-rank test. Polymorphic VPCs were more common in symptomatic dogs than asymptomatic. VPCs in dogs with VT were less premature, due to the influence of heart rate on PI despite comparable CI. The PI and mean heart rate (HRme) were significantly different between VT and non-VT dogs but did not discriminate adequately between groups as standalone tests. Median survival time was shorter in Boxer dogs with VT (463 vs 1645 days, HR: 4.31, P=0.03). The HRV parameters, SDNN and SDANN, were both associated with prognosis. The CI and PI were not demonstrated to be prognostic surrogates in Boxer dogs with VA. HRme112bpm is 100% sensitive but only 46% specific for detecting VT in Boxers on the 24-hour Holter. Presence of VT, SDNN245ms, or SDANN134ms at the time of the first 24-hour Holter was associated with a shorter survival.

RESUMO: Cães da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito (CAVD) podem apresentar morte súbita independentemente da presença/ausência de sinais clínicos. Os objetivos desse estudo retrospectivo foram: 1) investigar o intervalo de acoplamento (IA) e o índice de prematuridade (IP) das arritmias ventriculares e a variabilidade da frequência cardíaca (VFC) em Boxers, e 2) avaliar o impacto de tais características sob o tempo de sobrevida global. O primeiro Holter de 24 horas de 36 Boxers selecionados para os critérios de inclusão/exclusão foram avaliados para o número, morfologia, local de origem, complexidade, IA e IP dos complexos ventriculares prematuros (CVPs) e da VFC no domínio do tempo. O efeito na sobrevida foi avaliado, considerado a presença/ausência de taquicardia ventricular (TV), e síncope. O desfecho final foi a mortalidade global, com o tempo de sobrevida mediano sendo obtido pela análise de Kaplan-Meier e comparado pelo teste de log-rank. CVPs polimórficos foram mais comuns em cães sintomáticos. Os CVPs em Boxers com TV foram menos prematuros, devido à influência da frequência cardíaca (FC) sobre o IP, apesar de IA comparáveis. O IP e a FC média diferiram entre os cães com TV e os sem, mas não discriminam adequadamente os grupos como variáveis isoladas. A sobrevida global foi menor nos cães com TV (463 dias vs 1645 dias, HR=4,31, P=0,03). Os parâmetros da VFC, SDNN e SDANN, foram associados ao prognóstico. O IA e o IP não possuem valor prognóstico em Boxers com arritmias ventriculares. A FC média 112bpm é 100% sensível, mas apenas 46% específica para detectar Boxers com TV no Holter de 24 horas. A presença de TV, SDNN245ms, ou SDANN134ms no momento do primeiro Holter de 24 horas estão associados a menor sobrevida global no Boxer.

Prognostic value of coupling interval, prematurity index and heart rate variability in Boxer dogs / Valor prognóstico do intervalo de acoplamento, índice de prematuridade e variabilidade da frequência cardíaca em cães da raça Boxer

Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC) can experience sudden cardiac death regardless of presence/absence of clinical signs. The aims of this retrospective study were two-fold: 1) to investigate the coupling interval (CI) and prematurity index (PI) of ventricular arrhythmias (VA), and the heart rate variability (HRV) in Boxers, and 2) to evaluate their impact on overall survival time. The first 24-hour Holter 36 client-owned Boxer dogs meeting inclusion/exclusion criteria were evaluated for the number, morphology, site of origin, complexity, CI and PI, of ventricular premature complexes (VPCs), and time domain HRV. The effect on survival was assessed, considering the presence/absence of ventricular tachycardia (VT), and syncope. All-cause mortality was considered as the end-point, with median survival times being obtained by Kaplan-Meier analyses and compared by log-rank test. Polymorphic VPCs were more common in symptomatic dogs than asymptomatic. VPCs in dogs with VT were less premature, due to the influence of heart rate on PI despite comparable CI. The PI and mean heart rate (HRme) were significantly different between VT and non-VT dogs but did not discriminate adequately between groups as standalone tests. Median survival time was shorter in Boxer dogs with VT (463 vs 1645 days, HR: 4.31, P=0.03). The HRV parameters, SDNN and SDANN, were both associated with prognosis. The CI and PI were not demonstrated to be prognostic surrogates in Boxer dogs with VA. HRme≥112bpm is 100% sensitive but only 46% specific for detecting VT in Boxers on the 24-hour Holter. Presence of VT, SDNN≤245ms, or SDANN≤134ms at the time of the first 24-hour Holter was associated with a shorter survival.(AU)

Cães da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito (CAVD) podem apresentar morte súbita independentemente da presença/ausência de sinais clínicos. Os objetivos desse estudo retrospectivo foram: 1) investigar o intervalo de acoplamento (IA) e o índice de prematuridade (IP) das arritmias ventriculares e a variabilidade da frequência cardíaca (VFC) em Boxers, e 2) avaliar o impacto de tais características sob o tempo de sobrevida global. O primeiro Holter de 24 horas de 36 Boxers selecionados para os critérios de inclusão/exclusão foram avaliados para o número, morfologia, local de origem, complexidade, IA e IP dos complexos ventriculares prematuros (CVPs) e da VFC no domínio do tempo. O efeito na sobrevida foi avaliado, considerado a presença/ausência de taquicardia ventricular (TV), e síncope. O desfecho final foi a mortalidade global, com o tempo de sobrevida mediano sendo obtido pela análise de Kaplan-Meier e comparado pelo teste de log-rank. CVPs polimórficos foram mais comuns em cães sintomáticos. Os CVPs em Boxers com TV foram menos prematuros, devido à influência da frequência cardíaca (FC) sobre o IP, apesar de IA comparáveis. O IP e a FC média diferiram entre os cães com TV e os sem, mas não discriminam adequadamente os grupos como variáveis isoladas. A sobrevida global foi menor nos cães com TV (463 dias vs 1645 dias, HR=4,31, P=0,03). Os parâmetros da VFC, SDNN e SDANN, foram associados ao prognóstico. O IA e o IP não possuem valor prognóstico em Boxers com arritmias ventriculares. A FC média ≥112bpm é 100% sensível, mas apenas 46% específica para detectar Boxers com TV no Holter de 24 horas. A presença de TV, SDNN≤245ms, ou SDANN≤134ms no momento do primeiro Holter de 24 horas estão associados a menor sobrevida global no Boxer.(AU)

Prognostic value of coupling interval, prematurity index and heart rate variability in Boxer dogs / Valor prognóstico do intervalo de acoplamento, índice de prematuridade e variabilidade da frequência cardíaca em cães da raça Boxer

Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC) can experience sudden cardiac death regardless of presence/absence of clinical signs. The aims of this retrospective study were two-fold: 1) to investigate the coupling interval (CI) and prematurity index (PI) of ventricular arrhythmias (VA), and the heart rate variability (HRV) in Boxers, and 2) to evaluate their impact on overall survival time. The first 24-hour Holter 36 client-owned Boxer dogs meeting inclusion/exclusion criteria were evaluated for the number, morphology, site of origin, complexity, CI and PI, of ventricular premature complexes (VPCs), and time domain HRV. The effect on survival was assessed, considering the presence/absence of ventricular tachycardia (VT), and syncope. All-cause mortality was considered as the end-point, with median survival times being obtained by Kaplan-Meier analyses and compared by log-rank test. Polymorphic VPCs were more common in symptomatic dogs than asymptomatic. VPCs in dogs with VT were less premature, due to the influence of heart rate on PI despite comparable CI. The PI and mean heart rate (HRme) were significantly different between VT and non-VT dogs but did not discriminate adequately between groups as standalone tests. Median survival time was shorter in Boxer dogs with VT (463 vs 1645 days, HR: 4.31, P=0.03). The HRV parameters, SDNN and SDANN, were both associated with prognosis. The CI and PI were not demonstrated to be prognostic surrogates in Boxer dogs with VA. HRme≥112bpm is 100% sensitive but only 46% specific for detecting VT in Boxers on the 24-hour Holter. Presence of VT, SDNN≤245ms, or SDANN≤134ms at the time of the first 24-hour Holter was associated with a shorter survival.(AU)

Cães da raça Boxer com cardiomiopatia arritmogênica do ventrículo direito (CAVD) podem apresentar morte súbita independentemente da presença/ausência de sinais clínicos. Os objetivos desse estudo retrospectivo foram: 1) investigar o intervalo de acoplamento (IA) e o índice de prematuridade (IP) das arritmias ventriculares e a variabilidade da frequência cardíaca (VFC) em Boxers, e 2) avaliar o impacto de tais características sob o tempo de sobrevida global. O primeiro Holter de 24 horas de 36 Boxers selecionados para os critérios de inclusão/exclusão foram avaliados para o número, morfologia, local de origem, complexidade, IA e IP dos complexos ventriculares prematuros (CVPs) e da VFC no domínio do tempo. O efeito na sobrevida foi avaliado, considerado a presença/ausência de taquicardia ventricular (TV), e síncope. O desfecho final foi a mortalidade global, com o tempo de sobrevida mediano sendo obtido pela análise de Kaplan-Meier e comparado pelo teste de log-rank. CVPs polimórficos foram mais comuns em cães sintomáticos. Os CVPs em Boxers com TV foram menos prematuros, devido à influência da frequência cardíaca (FC) sobre o IP, apesar de IA comparáveis. O IP e a FC média diferiram entre os cães com TV e os sem, mas não discriminam adequadamente os grupos como variáveis isoladas. A sobrevida global foi menor nos cães com TV (463 dias vs 1645 dias, HR=4,31, P=0,03). Os parâmetros da VFC, SDNN e SDANN, foram associados ao prognóstico. O IA e o IP não possuem valor prognóstico em Boxers com arritmias ventriculares. A FC média ≥112bpm é 100% sensível, mas apenas 46% específica para detectar Boxers com TV no Holter de 24 horas. A presença de TV, SDNN≤245ms, ou SDANN≤134ms no momento do primeiro Holter de 24 horas estão associados a menor sobrevida global no Boxer.(AU)

Participation of the autonomic cardiac system in dogs with chronic myxomatous degeneration of the mitral valve / Participação do sistema autonômico cardíaco em cães com degeneração mixomatosa da válvula mitral

An exploratory multivariate analysis of factors of echocardiographic variables and those of the Holter test of 38 dogs with MVMD staged in three classes (class 1a, class 1b, class 2) of congestive heart failure proposed by the ISACHC. The purpose of this analysis was learning the processes that would explain the behavior of the variables described, using exploratory multivariate techniques of factors. Five independent factors were determined (PNS to SF) which altogether explain 82.17% of the shared variance of the data. It was identified that among the five factors, the first process (PNS) is the first factor in importance, recruiting the highest percentage of variance (37.96%) and represents the participation of the cardiac autonomic nervous system.(AU)

Foi realizada análise multivariada exploratória de fatores das variáveis ecocardiográficas e do exame Holter de 38 cães com DMVM estadiados em três classes (classe 1a, classe 1b, classe 2) da insuficiência cardíaca congestiva proposta pela ISACHC. O objetivo desta análise foi conhecer os processos que explicariam o comportamento das variáveis descritas, utilizando-se para esse fim técnicas multivariadas exploratórias de fatores. Foram determinados cinco fatores independentes (PNS até SF) que, em conjunto, explicam 82,17% da variância compartilhada dos dados. O primeiro processo (PNS) é o primeiro fator em importância, recrutando a maior porcentagem da variância total (37,96%) e representa a participação do sistema nervoso autônomo cardíaco.(AU)

Participation of the autonomic cardiac system in dogs with chronic myxomatous degeneration of the mitral valve / Participação do sistema autonômico cardíaco em cães com degeneração mixomatosa da válvula mitral

An exploratory multivariate analysis of factors of echocardiographic variables and those of the Holter test of 38 dogs with MVMD staged in three classes (class 1a, class 1b, class 2) of congestive heart failure proposed by the ISACHC. The purpose of this analysis was learning the processes that would explain the behavior of the variables described, using exploratory multivariate techniques of factors. Five independent factors were determined (PNS to SF) which altogether explain 82.17% of the shared variance of the data. It was identified that among the five factors, the first process (PNS) is the first factor in importance, recruiting the highest percentage of variance (37.96%) and represents the participation of the cardiac autonomic nervous system.(AU)

Foi realizada análise multivariada exploratória de fatores das variáveis ecocardiográficas e do exame Holter de 38 cães com DMVM estadiados em três classes (classe 1a, classe 1b, classe 2) da insuficiência cardíaca congestiva proposta pela ISACHC. O objetivo desta análise foi conhecer os processos que explicariam o comportamento das variáveis descritas, utilizando-se para esse fim técnicas multivariadas exploratórias de fatores. Foram determinados cinco fatores independentes (PNS até SF) que, em conjunto, explicam 82,17% da variância compartilhada dos dados. O primeiro processo (PNS) é o primeiro fator em importância, recrutando a maior porcentagem da variância total (37,96%) e representa a participação do sistema nervoso autônomo cardíaco.(AU)

Dysautonomia in a bitch with hypothyroidismˆien

Background: Thyroid hormones have important effects on the cardiovascular system, of which the main ones are the in-crease in the heart response to the autonomic sympathetic nervous system. Heart rate variability is a non-invasive method of assessing autonomic heart modulation, thus being an important form of evaluation in patients with thyroid dysfunctions. This study aimed to report electrocardiographic and heart rate variability data of a dog with hypothyroidism that presented a parasympathetic dysfunction.Case:A 7-year-old female Dalmatian dog was admitted for clinical evaluation in Fortaleza, Brazil. According to the owner, she had been apathetic for a year, had gained weight, always had a sad expression, and her hair was generally brittle and opaque. On physical examination, skin lesions were observed at the end of the spine, extending to the tail region, with the latter showing total alopecia. Low T4 levels confirmed the diagnosis of primary hypothyroidism. Then, a 24-h Holter monitoring was performed, which showed that the animal had sinus arrhythmia associated with moments of second-degree sinoatrial block and rare moments of sinus tachycardia. In addition, moments of premature multifocal ventricular extra-systoles and 1st-degree atrioventricular block were observed.Based on the Holter results, heart rate variability (HRV) was calculated. Regarding the HRV in the frequency domain, 32.16 was obtained in the low frequency (LF) band, 67.84 in the high frequency (HF) band, and the LF / HF ratio was 0.46, with a total power of 5205. As for the HRV in the time domain, RMSSD was 117, pNN50 was 62.64 and SDNN was 384. This showed an increase in the parasympathetic activity of the heart and, due to this increased activity, a...(AU)

Cardiomiopatia dilatada em cães: revisão de literatura / Dilated cardiomyopathy in dogs: literature review

A presente revisão tem por objetivo aprimorar o conhecimento sobre Dilated Cardiomyopathy (DCM) em cães, visando à compreensão dos aspectos clínicos, diagnóstico e tratamento. A DCM é caracterizada por dilatação ventricular, disfunção sistólica e arritmias que podem culminar em insuficiência cardíaca e morte. É a segunda cardiopatia mais frequente em cães, acometendo principalmente animais de grande porte e machos. A etiologia é idiopática, mas alguns genes associados à doença já foram identificados. A manifestação clínica é dividida basicamente em estágios oculto e sintomático. O estágio oculto é caracterizado pela presença de alterações elétricas e/ou morfológicas e ausência de sinais clínicos. Os cães podem apresentar o estágio oculto longo até o desenvolvimento de insuficiência cardíaca de forma aguda ou morte súbita. O estágio sintomático é definido pela presença de insuficiência cardíaca esquerda ou biventricular. O diagnóstico somente é confirmado por meio de ecocardiograma e/ou Holter. Estes exames são considerados padrão-ouro, uma vez que apresentam alta sensibilidade na identificação precoce da doença. Cães de raças predispostas devem ser monitorados anualmente a partir dos três anos de idade. O tratamento tem o intuito de minimizar os efeitos da insuficiência cardíaca, sendo instituído de acordo com a fase em que o animal se encontra. O prognóstico após início dos sinais clínicos é desfavorável. Alguns fatores podem influenciar a sobrevida de forma positiva ou negativa. A realização de exames periódicos é de grande importância para obter o diagnóstico precoce e intervir de maneira a retardar a progressão da doença.

The aim of the present review is to improve the knowledge about Cardiomyopathy dilata (CMD) in dogs, in order to understanding clinical aspects, diagnosis and treatment. CMD is characterized by ventricular dilation, systolic dysfunction, and arrhythmias that may culminate in heart failure and death. It is the second most common heart disease in dogs, affecting mainly large animals and males. The etiology is idiopathic, but some genes associated with the disease have already been identified. The clinical manifestation is basically divided into occult and symptomatic stages. The occult stage is characterized by the presence of electrical and/or morphological changes and absence of clinical signs. Dogs may present the long occult stage to the development of acute heart failure or sudden death. The symptomatic stage is defined by the presence of left or biventricular heart failure. The diagnosis is only confirmed by echocardiography and/or Holter. These exams are considered gold standard, since they present high sensitivity in the early identification of the disease. Dogs of predisposed breeds should be monitored annually from the age of three. The treatment is intended to minimize the effects of heart failure, and is instituted according to the stage in which the animal is. The prognosis after onset of clinical signs is worse. Some factors may influence survival in a positive or negative way. Periodic examinations are great importance to obtain early diagnosis and interpose in order to delay the progression of the disease.

Dysautonomia in a bitch with hypothyroidismˆien

Background: Thyroid hormones have important effects on the cardiovascular system, of which the main ones are the in-crease in the heart response to the autonomic sympathetic nervous system. Heart rate variability is a non-invasive method of assessing autonomic heart modulation, thus being an important form of evaluation in patients with thyroid dysfunctions. This study aimed to report electrocardiographic and heart rate variability data of a dog with hypothyroidism that presented a parasympathetic dysfunction.Case:A 7-year-old female Dalmatian dog was admitted for clinical evaluation in Fortaleza, Brazil. According to the owner, she had been apathetic for a year, had gained weight, always had a sad expression, and her hair was generally brittle and opaque. On physical examination, skin lesions were observed at the end of the spine, extending to the tail region, with the latter showing total alopecia. Low T4 levels confirmed the diagnosis of primary hypothyroidism. Then, a 24-h Holter monitoring was performed, which showed that the animal had sinus arrhythmia associated with moments of second-degree sinoatrial block and rare moments of sinus tachycardia. In addition, moments of premature multifocal ventricular extra-systoles and 1st-degree atrioventricular block were observed.Based on the Holter results, heart rate variability (HRV) was calculated. Regarding the HRV in the frequency domain, 32.16 was obtained in the low frequency (LF) band, 67.84 in the high frequency (HF) band, and the LF / HF ratio was 0.46, with a total power of 5205. As for the HRV in the time domain, RMSSD was 117, pNN50 was 62.64 and SDNN was 384. This showed an increase in the parasympathetic activity of the heart and, due to this increased activity, a...

Cardiomiopatia dilatada em cães: revisão de literatura / Dilated cardiomyopathy in dogs: literature review

A presente revisão tem por objetivo aprimorar o conhecimento sobre Dilated Cardiomyopathy (DCM) em cães, visando à compreensão dos aspectos clínicos, diagnóstico e tratamento.  A DCM é caracterizada por dilatação ventricular, disfunção sistólica e arritmias que podem culminar em insuficiência cardíaca e morte. É a segunda cardiopatia mais frequente em cães, acometendo principalmente animais de grande porte e machos. A etiologia é idiopática, mas alguns genes associados à doença já foram identificados. A manifestação clínica é dividida basicamente em estágios oculto e sintomático. O estágio oculto é caracterizado pela presença de alterações elétricas e/ou morfológicas e ausência de sinais clínicos. Os cães podem apresentar o estágio oculto longo até o desenvolvimento de insuficiência cardíaca de forma aguda ou morte súbita. O estágio sintomático é definido pela presença de insuficiência cardíaca esquerda ou biventricular. O diagnóstico somente é confirmado por meio de ecocardiograma e/ou Holter.  Estes exames são considerados padrão-ouro, uma vez que apresentam alta sensibilidade na identificação precoce da doença. Cães de raças predispostas devem ser monitorados anualmente a partir dos três anos de idade. O tratamento tem o intuito de minimizar os efeitos da insuficiência cardíaca, sendo instituído de acordo com a fase em que o animal se encontra. O prognóstico após início dos

The aim of the present review is to improve the knowledge about Cardiomyopathy dilata (CMD) in dogs, in order to understanding clinical aspects, diagnosis and treatment. CMD is characterized by ventricular dilation, systolic dysfunction, and arrhythmias that may culminate in heart failure and death. It is the second most common heart disease in dogs, affecting mainly large animals and males. The etiology is idiopathic, but some genes associated with the disease have already been identified. The clinical manifestation is basically divided into occult and symptomatic stages. The occult stage is characterized by the presence of electrical and/or morphological changes and absence of clinical signs. Dogs may present the long occult stage to the development of acute heart failure or sudden death. The symptomatic stage is defined by the presence of left or biventricular heart failure. The diagnosis is only confirmed by echocardiography and/or Holter. These exams are considered gold standard, since they present high sensitivity in the early identification of the disease. Dogs of predisposed breeds should be monitored annually from the age of three. The treatment is intended to minimize the effects of heart failure, and is instituted according to the stage in which the animal is. The prognosis after onset of clinical signs is worse. Some factors may influence survival in a positive or negative way. Periodic examinations are great importance to obtain early diagnosis and interpose in order to delay the progression of the disease.(AU)

Cardiomiopatia dilatada em cães: revisão de literatura / Dilated cardiomyopathy in dogs: literature review

A presente revisão tem por objetivo aprimorar o conhecimento sobre Dilated Cardiomyopathy (DCM) em cães, visando à compreensão dos aspectos clínicos, diagnóstico e tratamento.  A DCM é caracterizada por dilatação ventricular, disfunção sistólica e arritmias que podem culminar em insuficiência cardíaca e morte. É a segunda cardiopatia mais frequente em cães, acometendo principalmente animais de grande porte e machos. A etiologia é idiopática, mas alguns genes associados à doença já foram identificados. A manifestação clínica é dividida basicamente em estágios oculto e sintomático. O estágio oculto é caracterizado pela presença de alterações elétricas e/ou morfológicas e ausência de sinais clínicos. Os cães podem apresentar o estágio oculto longo até o desenvolvimento de insuficiência cardíaca de forma aguda ou morte súbita. O estágio sintomático é definido pela presença de insuficiência cardíaca esquerda ou biventricular. O diagnóstico somente é confirmado por meio de ecocardiograma e/ou Holter.  Estes exames são considerados padrão-ouro, uma vez que apresentam alta sensibilidade na identificação precoce da doença. Cães de raças predispostas devem ser monitorados anualmente a partir dos três anos de idade. O tratamento tem o intuito de minimizar os efeitos da insuficiência cardíaca, sendo instituído de acordo com a fase em que o animal se encontra. O prognóstico após início dos

The aim of the present review is to improve the knowledge about Cardiomyopathy dilata (CMD) in dogs, in order to understanding clinical aspects, diagnosis and treatment. CMD is characterized by ventricular dilation, systolic dysfunction, and arrhythmias that may culminate in heart failure and death. It is the second most common heart disease in dogs, affecting mainly large animals and males. The etiology is idiopathic, but some genes associated with the disease have already been identified. The clinical manifestation is basically divided into occult and symptomatic stages. The occult stage is characterized by the presence of electrical and/or morphological changes and absence of clinical signs. Dogs may present the long occult stage to the development of acute heart failure or sudden death. The symptomatic stage is defined by the presence of left or biventricular heart failure. The diagnosis is only confirmed by echocardiography and/or Holter. These exams are considered gold standard, since they present high sensitivity in the early identification of the disease. Dogs of predisposed breeds should be monitored annually from the age of three. The treatment is intended to minimize the effects of heart failure, and is instituted according to the stage in which the animal is. The prognosis after onset of clinical signs is worse. Some factors may influence survival in a positive or negative way. Periodic examinations are great importance to obtain early diagnosis and interpose in order to delay the progression of the disease.

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.