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 QRS complexes 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 and that there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiac autonomic 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 parasympathetic predominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other 2 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 natural tendency 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 heart diseases presents interesting perspectives. However, before it may be employed for these purposes, a better understanding should be established regarding the physiological behavior of autonomic cardiac modulation in different age groups to serve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter RR intervals than the other groups (adult and elderly dogs), what was observed on Holter and heart rate monitor methods (HRM). There were significant differences between puppies and the other 2 groups (adults and elderly) for all time-domain variables using both methods (Holter and HRM methods). SDNN was significantly lower in puppies compared to adults and elderly dogs. In addition, both RMSSD and PNN50%, which were more reliable over shorter periods of time, also presented means and medians that were significantly lower in puppies. Regarding frequency-domain HRV parameters observed on Holter method, these indexes were decreased on the elderly group compared to adult dogs, which is a possible effect of aging. Also, puppies revealed lower frequency-domain HRV parameters on both methods when compared to adult dogs. The influence of age on HRV is possibly related to the stage of development of an individual, starting at conception up to the maturity in relation to the mechanisms that cause variations in HR. There are studies in humans that suggest a gradual increase in parasympathetic activity during childhood, followed by a steady decrease as aging occur. The present study observed the same pattern in dogs. The balance between sympathetic and parasympathetic systems is influenced by age in dogs, which alters HRV values in the short-term. The HRV method´s analysis is relatively simple and non-invasive for assessing cardiac autonomic function; also, it is widely used in human medicine as a risk measure for sudden cardiac death. The 24-hour HRV analysis is highly challenging, as it is time-consuming, expensive, delays diagnosis, and has a large number of artifacts; in this way, standards for its short-term analysis were developed. Keywords: cardiology, autonomic nervous system, heart rate monitor, Holter

Análise do perfil hemostático e do risco tromboembólico em cães submetidos ao tratamento com prednisona

Os distúrbios trombóticos e tromboembólicos aparentemente são menos comuns em felinos e caninos do que em humanos. A trombose foi reconhecida clinicamente associada a algumas doenças, como o hiperadrenocorticismo (HAC). Vários fármacos podem alterar o equilíbrio hemostático; dentre elas a prednisona, corticosteroide amplamente utilizado na medicina veterinária principalmente por seus efeitos imunossupressivos e anti-inflamatórios. Além disso, sabe-se que o hipercortisolismo pode estimular a formação de trombos pelo aumento de fatores de coagulação e diminuição da fibrinólise. O objetivo do presente estudo, portanto, foi demonstrar o efeito da prednisona sobre o perfil hemostático. Para tanto, foram constituídos dois grupos experimentais, sendo o grupo I, composto de 10 cães hígidos que receberam a dose de 1,0 mg/kg/BID por 15 dias, e ogrupo II, composto de 10 cães hígidos que receberam a dose de 2,0 mg/kg/BID por 15 dias. Houve diminuição significativa dos níveis de antitrombina em ambos os grupos, aumento da agregação plaquetária e diminuição do fator de von Willebrand no grupo II. Não foram observadas alterações estatisticamente significativas em relação ao tempo de sangramento da mucosa oral (TSMO), tempo de protrombina (TP), tempo de tromboplastina parcial ativada (TTPA), tempo de trombina (TT), contagem plaquetária, e dos valores de fibrinogênio, fator VIII e produtos de degradação da fibrina (PDFs) em nenhum dos grupos. Pode-se concluir que a prednisona pode aumentar o risco tromboembólico especialmente por diminuição de fatores anticoagulantes, não importando a dose utilizadaThrombotic and thromboembolic disorders apparently are less common in cats and dogs than in humans.Thrombosis was clinically recognized associated with some diseases, such as hyperadrenocorticism (HAC). Several drugs can change the hemostatic balance, such as the corticosteroid prednisone, widely used in veterinary medicine mainly by its immunosuppresive and anti-inflammatory effects. In addition, it is known that hypercortisolism can stimulate the thrombi formation by the increase of coagulation factors and reduced fibrinolysis.The aim of this study, therefore, was to demonstrate the effect of prednisone on haemostatic profile. For this purpose, two experimental groups were set up, the group I composed by 10 higid dogs, which received a dose of 1,0 mg/kg/BID for 15 days, and group II, composed by 10 higid dogs that received the dose of 2,0 mg/kg/BID for 15 days.There was a significant decrease on antithrombin levels in both groups, increase on platelet aggregation and decrease of von Willebrand factor activity on group II. No statistically significant changes were observed in relation to oral mucosal bleeding time (OMBT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), platelet count, plasmatic fibrinogen values,factor VIII activityand fibrin degradation products (FDPs) in both groups. It can be concluded that the prednisone can increase the thromboembolic risk, especially by the decrease of anticoagulant factors, regardless of the dosageFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Main risk factors of dogs with congestive heart failure diagnosed by doppler echocardiographic parameters

Nowadays, congestive heart failure is one of the major complications of heart disease in small animals, which is characterized by a clinical condition in which the heart is unable to eject the blood efficiently. At long term, some compensatory mechanisms it will eventually become detrimental and, mainly, due to the congestion caused by it. In dogs, the main cause of CHF is chronic mitral valve degeneration, it is responsible for the degeneration of collagen present in the mitral valve structure that will have detrimental consequences on the entire circulatory system. The aim of the present study was to perform a retrospective study of 498 echocardiographic reports collected at a veterinary cardiology service of the Bauru region, from January 2017 to June 2019. Two groups were formed according to the Doppler echocardiographic alterations found, one that included animals with characteristics of congestive heart failure (CHF), and the other formed by non-CHF patients. Of the total number of animals evaluated, 61 were classified as affected by congestive heart failure and after classification, it was considered the main epidemiological factors (race, sex and age) of animals belonging to this group. Small breed animals were overrepresented and also elderly animals, with no apparent sexual predisposition. In addition, animals with CHF presented higher values when compared to animals without CHF of LA/Ao ratio (2.31 ± 0.30 vs. 1.46 ± 0.35), E/IRTV ratio (2.96 ± 0.39 vs. 1.16 ± 0.43) and E-wave velocity (1.45 m/s ± 0.18 vs. 0.75 m/s ± 0.22) on echocardiographic examination

Manejo da insuficiência renal aguda em cães e gatos

Acute renal failure (ARF) may be defined as a subtle loss of renal function, leading to accumulation of nitrogenated substances. Several causes may lead to the development of ARF in an animal, including severe shock, intense blood loss, hypotension, dehydration, hypovolemia, deep anesthesia and nephrotoxins. Fluid therapy remains the basis of ARF treatment in animals. Thee therapeutic objective is to normalize fluid balance, solve hemodynamic problems and promote urine production. The objective of the present study is to review the procedures to manage acute renal failure in dogs and cats.La insuficiencia renal aguda (IRA) puede ser definida como pérdida de la función renal de manera súbita, causando acumulación de sustancias nitrogenadas. Varias causas pueden llevar al desarrollo de IRA en un animal, incluyendo: choque grave, hemorragia intensa, hipotensión, deshidratación, hipovolemia, anestesia profunda y nefrotoxinas. La fluidoterapia sigue siendo la base para el tratamiento clínico de IRA en los animales. El objetivo terapéutico es normalizar el equilibrio hídrico, resolver las inadecuaciones hemodinámicas y promover la formación de orina. El objetivo de este estudio es revisar sobre el manejo de la insuficiencia renal aguda en perros y gatos.A insuficiência renal aguda (IRA) pode ser definida como perda da função renal de maneira súbita, provocando acúmulo de substâncias nitrogenadas. Diversas causas podem levar ao desenvolvimento de IRA em um animal, incluindo: choque grave, hemorragia intensa, hipotensão, desidratação, hipovolemia, anestesia profunda e nefrotoxinas. A fluidoterapia permanece como o fundamento do tratamento clínico da IRA nos animais. O objetivo terapêutico é normalizar o equilíbrio hídrico, resolver as inadequações hemodinâmicas e promover a formação de urina. O objetivo do presente trabalho é revisar sobre o manejo da insuficiência renal aguda em cães e gatos

Pesquisa dos genes lipA e aprX em linhagens de Corynebacterium bovis, e seu crescimento sob refrigeração

Some microorganisms frequently found in the raw milk of mastitics animals have the hability of multiplying in low temperatures, being called of psychotropic, and in this group, some have still the capacity to produce term steady enzymes that degrade proteins and fats, promoting relevant alterations in long periods stored milk. The present study aimed to determine if Corynebacterium bovis has the capacity to multiply in low temperature and if it had aprX and lipA genes, producing enzymes that degrade proteins and fats of the milk stored by long periods of time. The agent was incubated by 10 consecutive days in refrigeration, varying between 0.7 to 4ºC, and daily reading of absorbance (A) in spectrophotometer each 24 hours (M0 to M9 moments). The gene presence was accomplished with polimerase chain reaction (PCR). The results revealed that C. bovis is capable to multiply under refrigeration after 120 hours of incubation as observed between the moments M5 (A=0.264) and M6 (A=0.297) where P<0.05 confirming as psychotropic agent. In the other hand the studied microorganism doesn't possess the lipA and aprX genes, therefore it is not capable to produce the enzymes codified by these genes, what doesn't mean that C. bovis doesn't possess genes for the production of other degrading enzymes, don’t researched in the present study. This suggests that new studies of the genome of this microorganism are necessary, to elucidate this agent's true paper in the alteration of the quality of the milk and of their products.Algunos microorganismos comúnmente encontrados en la leche cruda de animales mastíticos tienen la capacidad de multiplicarse en temperaturas de refrigeración, siendo llamados psicotróficos, y en este grupo, algunos aún tienen la capacidad de producir enzimas termoestables, que degradan proteínas y lípidos, promoviendo importantes alteraciones en la leche almacenada por longos períodos de tiempo. El presente estudio objetivó determinar si Corynebacterium bovis tiene la capacidad de multiplicarse en temperatura de refrigeración y si tiene los genes aprX y lipA, productores de enzimas que degradan proteínas y gorduras de la leche almacenada por longos períodos de tiempo. El agente fue incubado en 0,7 y 4ºC, por 10 días consecutivos, con la aferición de los valores de absorbencia (A) en espectrofotómetro por cada 24 horas (momentos M0 hasta M9). Para la verificación de la presencia de los genes fue realizada la reacción en cadena por la polimerasa (PCR). Los resultados revelaron que C. bovis puede multiplicarse en refrigeración después de 120 horas de incubación donde hubo diferencia significante con P<0,05 entre los períodos M5 (A=0,264) y M6 (A=0,297) considerado psicotrófico. Por otro lado, no tiene los genes aprX y lipA, no produciendo las enzimas codificadas por estos genes, lo que no significa que C. bovis no tiene genes para la producción de otras enzimas degradantes, no pesquisadas en el presente estudio. Eso sugiere que nuevos estudios del genoma de este microorganismo son necesarios para elucidar el verdadero papel de este agente en la alteración de la calidad de la leche y de sus subproductos.Alguns micro-organismos comumente encontrados no leite cru de animais mastíticos possuem a capacidade de se multiplicar em temperaturas de refrigeração, sendo denominados de psicrotróficos, e neste grupo, alguns têm ainda a capacidade de produzir enzimas termoestáveis, que degradam proteínas e lipídeos, promovendo alterações importantes no leite armazenado por longos períodos de tempo. O presente estudo objetivou determinar se Corynebacterium bovis possui a capacidade de se multiplicar em temperatura de refrigeração e se possui os genes aprX e lipA, produtores de enzimas que degradam proteínas e gorduras do leite armazenado por longos períodos de tempo. O agente foi incubado a 0,7 e 4ºC, por 10 dias consecutivos, com a aferição dos valores de absorbância (A) em espectrofotômetro a cada 24 horas (momentos M0 à M9). Para a verificação da presença dos genes foi realizada a técnica da reação em cadeia pela polimerase (PCR). Os resultados revelaram que C. bovis é capaz de se multiplicar sob refrigeração após 120 horas de incubação onde houve diferença significante com P<0,05 entre os períodos M5(A=0,264) e M6(A=0,297) considerado-o como psicrotrófico. Por outro lado, não possui os genes aprX e lipA, não produzindo as enzimas codificadas por estes genes, o que não significa que o C. bovis não possua genes para a produção de outras enzimas degradantes, não pesquisadas no presente estudo. Isto sugere que novos estudos do genoma deste micro-organismo são necessários, para se elucidar o verdadeiro papel deste agente na alteração da qualidade do leite e de seus subprodutos

Evaluation of the occurrence of metabolic syndrome in obese dogs and the role of caloric restriction diet as an adjuvant therapy

Metabolic syndrome, or metabolic dysfunction related to obesity in dogs, is a set of factors that may predispose comorbidities secondary to obesity. Adjuvant therapy with an energy-restricted diet, especially with low levels of carbohydrate and fat, is essential for weight loss, in addition to controlling snacks intake. The aim of this study was to evaluate the biochemical profile of obese dogs compared to lean dogs, and also to compare these profiles before and after a 30-day treatment, thus evaluating the possibility of obesity-related metabolic dysfunction and the action of adjuvant dietary therapy in this condition. Cholesterol and its fractions (HDL, LDL and VLDL), triglycerides, systemic blood pressure and glycemia of obese and lean dogs were measured, and seven obese dogs were treated only with a low-calorie diet with low levels of fat and carbohydrates for 30 days; these patients were evaluated before and after treatment. Obese dogs showed higher levels of triglycerides than lean dogs, and dogs treated with low-calorie diet presented weight loss and better outcomes related to biochemical profile, especially triglycerides levels, after treatment

Doença cerebelar em cães e gatos

Diseases of the cerebellar system are common in small animals, and result in a clinical syndrome characterized by hypermetria, base-wide stance and intentional tremors of the head and body. All movements of the limbs are spastic and awkward. The neurological examination assists in the localization of lesions restricted to the cerebellum or in the detection of disorders relating to other parts of the nervous system, which characterizes a multifocal disease process. Neurological disorders in dogs and cats may suggest a very extensive list of differential diagnoses, since they may be caused by infectious, degenerative and traumatic processes, among others. The possible etiologies for cerebellar syndrome include: aplasia and hypoplasia, abiotrophy, cancer, vascular stroke and inflammatory disorders. The aim of this paper is to review the clinical signs that aid in the location of the cerebellar lesion and discuss the possible causes of this syndrome in dogs and cats.Los trastornos del sistema cerebeloso son comunes en los pequeños animales, y dan lugar a un síndrome clínico caracterizado por hipermetría, aumento de la base de apoyo y temblores de la cabeza y del tronco. Todos los movimientos de las extremidades son espásticos e incoordinados. El examen neurológico ayuda en la localización de las lesiones en el cerebelo o en la detección de los trastornos relacionados con otras partes del sistema nervioso, caracterizando así una enfermedad multifocal. Los trastornos neurológicos en perros y gatos pueden tener origen en una gran cantidad de procesos infecciosos, degenerativos y traumáticos, entre otros. Las posibles causas para el síndrome cerebeloso son: aplasia o hipoplasia, abiotrofia, cáncer, derrames vasculares e inflamatórias. El objetivo de este trabajo es revisar los signos clínicos que ayuden en la localización de la lesión cerebelosa y discutir las posibles causas de este síndrome en perros y gatos.As doenças do cerebelo são comuns em pequenos animais e resultam em uma síndrome clínica caracterizada por hipermetria, base ampla de sustentação e tremores intencionais de cabeça e tronco. Todos os movimentos dos membros são espásticos e desajeitados. O exame neurológico auxilia a localização de lesões cerebelares ou a detecção de disfunções relativas a outras porções do sistema nervoso, caracterizando um processo patológico multifocal. As afecções neurológicas de cães e gatos podem sugerir uma lista muito extensa de diagnósticos diferenciais, pois podem ser causadas por processos infecciosos, degenerativos e traumáticos, entre outros. As possíveis etiologias para a síndrome cerebelar incluem: aplasia, hipoplasia, abiotrofia, neoplasia, infarto vascular e distúrbios inflamatórios. O objetivo do presente trabalho é revisar os sinais clínicos que auxiliam na localização da lesão cerebelar e discorrer sobre as possíveis causas dessa síndrome em cães e gatos