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

Physiological effects of land and water treadmill exercise in dogs / Efeitos do exercício em esteira terrestre ou aquática sobre os parâmetros fisiológicos de cães

The application of hydrotherapy is growing in the field of animal rehabilitation to improve strength, endurance, fitness, and range of motion, in addition to reducing pain. In the same way, land-based activity is recommended for various conditions, including hypertension, muscle atrophy, and obesity. There is a lack of studies that evaluate the safety of incremental exercise in American Pit Bull Terriers. This study assessed the influence of activity on underwater and dry land treadmills on the physiological parameters of dogs. In this regard, 12 adult, male, healthy, and untrained American Pit Bull Terriers were subjected to an incremental exercise test (IET) on the underwater treadmill (Group I) and the dry land treadmill (Group II). Heart rate (HR), respiratory rate (RR), rectal temperature (RT), systolic blood pressure (SBP), and electrocardiographic evaluation, were evaluated before activity (T0), immediately after (T1), 30 min after (T2), and 90 min after the end of exercise (T3), and plasmatic lactate concentrations were measured at T0, T1, and T2 time points. Results obtained were submitted to the Shapiro-Wilk test, ANOVA and Tukey's test, considering P<0.05. Water activity induced a reduction in RR (P=0.00674) in all examinations after the test on the underwater treadmill and proved to be more demanding than activity on the land treadmill, considering the presence of a deeper and slower RR. Exercise sessions in both groups did not elevate the lactate concentration. The IET can be performed safely on an underwater or dry land treadmill in healthy American Pit Bulls.

A hidroterapia apresenta crescente aplicação no ramo da reabilitação animal, com o intuito de aumentar a força, resistência muscular e amplitude de movimento articular, além de reduzir a dor e melhorar o condicionamento físico do paciente. Assim como a hidroterapia, a atividade desenvolvida em solo é indicada para diversas afecções, inclusive para pacientes hipertensos, com atrofia muscular ou com sobrepeso. São escassos os estudos que avaliam a segurança de testes incrementais em esteira aquática e em esteira seca em American Pit Bull Terriers. Este estudo teve como objetivo avaliar os efeitos da atividade em esteira aquática e em esteira seca sobre os parâmetros fisiológicos de cães. Para isto, cães da raça American Pit Bull Terrier (n=12) machos, adultos, saudáveis e não treinados foram submetidos a teste de esforço incremental (TEI) em hidroesteira com água (Grupo I) e sem água (Grupo II). A frequência cardíaca (FR), frequência respiratória (FR), temperatura retal (TR), pressão arterial sistólica (PAS) e avaliação eletrocardiográfica, foram aferidas antes da atividade (T0), imediatamente após (T1), 30 minutos após (T2) e 90 minutos após o exercício (T3), e a concentração plasmática de lactato foi dosada nos momentos T0, T1 e T2. Os resultados foram submetidos ao teste de Shapiro-Wilk, análise de variância (ANOVA) e pelo Teste de Tukey, considerando significativo o valor de P < 0.05. Houve diminuição da frequência respiratória (P = 0,00674) após a atividade em esteira aquática, que se mostrou mais exigente que a atividade em esteira terrestre, considerando a apresentação de padrão respiratório mais lento e profundo. As sessões de exercício em ambos os grupos não elevaram a concentração de lactato. O teste de esforço incremental em esteira aquática, ou em esteira seca, pode ser desenvolvido com segurança por cães American Pit Bull saudáveis.

Dexmedetomidine for chemical restraint of a Brazilian tapir (Tapirus terrestris)

Background: The Brazilian tapir (Tapirus terrestris), considered the largest land mammal in South America, is a vulnerable species in terms of its degree of conservation. In captivity, its health is evaluated through behavioral and physical observation and laboratory exams, and in some cases, chemical restraint, to reduce stress. Dissociative anesthetics and sedatives are used for the sedation of these animals, and few studies have reported the use of dexmedetomidine and its effects when associated with other drugs in chemical containment protocols; therefore, this work reports its use, in conjunction with ketamine and midazolam, in a young Brazilian tapir. Case: A male Brazilian tapir, male, weighing 89 kg, 1 and a half year old, housed at CETAS in Rio Branco, Acre, was chemically restrained with dexmedetomidine (7 µg/kg), ketamine (1.5 mg/kg), and midazolam (0.2 mg/kg) for venous blood collection, oral and rectal mucosal swabs, and microchipping. The protocol was administered intramuscularly to the right triceps brachii, after physical restraint. After 5 min of application, the animal assumed sternal recumbency and presented reflux. After 15 min, the patient was placed in the right lateral decubitus position. During collection, heart rate (48 ± 10 bpm), respiratory frequency (29 ± 1 mpm), rectal temperature (38.1 ± 0.18°C), oxyhemoglobin saturation (97 ± 1%), and electrocardiographic tracing were recorded. The tapir showed deep sedation, immobility, good muscle relaxation, discreet medial palpebral reflex, and bilateral rotation of the eyeball. After 40 min of protocol administration, sedative reversal was performed intramuscularly with 14 µg/kg atipamezole. Five min after administration, the tapir showed signs of mild sedation. After 10 min, he assumed the quadrupedal position, remained in this position for 8 min, and gently resumed the sternal decubitus. After only 20 min, he resumed the quadrupedal position, with mild ataxia and good muscular and conscious tone. After 50 min, the patient was discharged from anesthesia. Discussion: Domestic horses are phylogenetically close to tapirs, so the choice of drugs and doses of the protocol used was based on their use in horses, and on studies carried out with tapirs as well. Despite being docile and passive, the tapir was not conditioned and did not allow the manipulation and collection of samples collaboratively; therefore, it was chemically contained. The physical restraint performed did not generate satisfactory immobilization of the tapir, resulting in agitation and stress and causing the needle to break. The reflux presented by the tapir minutes after sedation and at recovery was induced by dexmedetomidine, and only the undigested banana pieces were offered to the animal. Reflux plus stress from extensive fasting and suboptimal physical restraint was responsible for the change in the tapir's eating behavior, with possible stress gastritis 24 h after chemical restraint. Only one study reported the use of dexmedetomidine in tapirs, associated with continuous infusions of ketamine, midazolam and guaiacol glyceryl ether for moderate to long-term field procedures. Sedative reversal of dexmedetomidine by atipamezole reduced the recovery time and the risk of death from cardiorespiratory depression. The anesthetic combination used was effective, promoting immobility, muscle relaxation, and stability of the physical parameters evaluated, with rapid and gentle induction and an adequate level of sedation for the objective, good sedative reversal, and anesthetic recovery.

Infusão contínua de fentanil e cetamina para controle de dor no transcirurgico: relato de caso / Continuous infusion of fentanyl and ketamine for trans-surgical pain control: case report

O paciente da espécie canina, sem raça definida, com 5 anos, deu entrada a clínica veterinária particular apresentando quadro de dor aguda e intensa em cavidade abdominal associada a prostração. Foram realizados exames de sangue, ultrassonografia e radiografia de abdômen, cuja suspeita foi torção parcial do estômago, com esplenomegalia, além de gastrite e enterite. O paciente foi submetido imediatamente ao procedimento cirúrgico para alívio, reposicionamento do órgão e gastropexia. O animal foi medicado previamente com metadona, tramadol e dipirona duas horas antes do ato cirúrgico, portanto não foram utilizadas medicações pré-anestésicas e optou-se pelo propofol e cetamina para a indução anestésica, além da infusão contínua com cetamina e fentanil para se obter a analgesia multimodal. Os parâmetros de dor foram avaliados por meio das frequências cardíaca e respiratória, traçado eletrocardiográfico, pressão arterial sistólica e média, aferição da temperatura retal e coloração de mucosas, a cada 5 minutos. Os mesmos indicaram boa estabilidade hemodinâmica, segurança e analgesia, sem necessidade de alterar as doses estabelecidas durante o procedimento. Pode ser observada também redução do requerimento de isoflurano para manutenção do plano cirúrgico. O paciente acordou sem sinais de dor no pós-operatório imediato evitando estresse sistêmico, o que conferiu o bom resultado do protocolo analgésico instituído.

The patient (Caramel) canine, mixed breed, approximately 5 years old, weighing 26kg was seen at the Ame Vet veterinary clinic, with severe abdominal pain, apathy, anorexia, prostration. Blood tests, abdominal ultrasound and abdominal x-ray were performed according to the tests a suspicion of partial torsion of the stomach and splenomegaly with right displacement, in addition to gastritis and enteritis. It was decided by the clinic and surgeon to perform laparotomy and prophylactic gastropexy. The animal was previously medicated by the clinic that treated the animal for analgesia with methadone, tramadol and dipyrone two hours before the beginning of the surgical procedure, therefore, pre-anesthetic medications, anesthetic induction with propofol, and ketamine were not used, aiming to perform analgesia. Multimodal with continuous infusion of ketamine and fentanyl, that is, more than one different mechanism of action, acting synergistically and reducing dose-dependent adverse effects and monitoring hemostasis and patient parameters, presenting its efficacy and safety in intraoperative pain control. The parameters addressed were heart rate (HR), respiratory rate (RR), electrocardiographic tracing, Spo2, systolic blood pressure (SBP), mean arterial pressure (MAP), temperature and mucosal color, evaluated every 5 minutes. The parameters evaluated indicated good hemodynamic stability, safety and analgesia, with no need to change the doses established during the procedure. A reduction in the requirement of isoflurane to maintain the surgical plan can also be observed. The patient woke up without signs of pain in the immediate postoperative period, thus avoiding systemic stress. which conferred the good result of the analgesic protocol instituted.

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)

Sedative and electrocardiographic effects of low dose dexmedetomidine in healthy cats / Efeitos sedativos e eletrocardiográficos da baixa dose de dexmedetomidina em gatos saudáveis

In feline veterinary practice sedation is often needed to perform diagnostic or minimally invasive procedures, minimize stress, and facilitate handling. The mortality rate of cats undergoing sedation is significantly higher than dogs, so it is fundamental that the sedatives provide good cardiovascular stability. Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist utilized in cats to provide sedation and analgesia, although studies have been utilized high doses, and markedly hemodynamic impairments were reported. The aim of this study was to prospectively investigate how the sedative and electrocardiographic effects of a low dose of DEX performing in cats. Eleven healthy cats were recruited; baseline sedative score, systolic arterial pressure, electrocardiography, and vasovagal tonus index (VVTI) were assessed, and repeated after ten minutes of DEX 5μg/kg intramuscularly (IM). A smooth sedation was noticed, and emesis and sialorrhea were common adverse effects, observed on average seven minutes after IM injection. Furthermore, electrocardiographic effects of a low dose of DEX mainly include decreases on heart rate, and increases on T-wave amplitude. The augmentation on VVTI and appearance of respiratory sinus arrhythmia, as well as sinus bradycardia in some cats, suggesting that DEX enhances parasympathetic tonus in healthy cats, and therefore will be best avoid in patients at risk for bradycardia.(AU)

Na rotina clínica da medicina veterinária felina a sedação é frequentemente requerida para realização de procedimentos diagnósticos ou minimamente invasivos, para minimizar o estresse e facilitar o manuseio dos pacientes. A taxa de mortalidade de gatos submetidos à sedação é mais elevada do que em cães, por esse motivo, é fundamental que os sedativos confiram estabilidade hemodinâmica. A dexmedetomidina (DEX) é um α2-agonista utilizado em felinos para promover sedação e analgesia, porém os estudos têm utilizado doses elevadas, e com isso prejuízos hemodinâmicos importantes foram relatados. O objetivo desta investigação foi avaliar os efeitos sedativos e eletrocardiográficos da baixa dose de DEX em gatos. Para tal, onze felinos saudáveis foram recrutados, foram obtidos valores basais para escore de sedação, pressão arterial sistólica e eletrocardiografia, além do índice de tônus vaso vagal (ITVV). Após dez minutos da aplicação intramuscular (IM) de DEX 5μg/kg todos os exames foram repetidos. Após a DEX, sedação suave foi detectada, e a êmese e sialorreia foram efeitos adversos comuns, observados em média 7 minutos após a injeção IM. Ademais, os principais efeitos eletrocardiográficos foram redução na frequência cardíaca e aumento na amplitude da onda T. O ITVV mais elevado e surgimento de arritmia sinusal respiratória, bem como bradicardia sinusal em alguns gatos, sugerem que a DEX eleva o tônus parassimpático, e por esse motivo deve ser utilizada com cautela em pacientes com predisposição à bradicardia.(AU)

Sedative and electrocardiographic effects of low dose dexmedetomidine in healthy cats / Efeitos sedativos e eletrocardiográficos da baixa dose de dexmedetomidina em gatos saudáveis

In feline veterinary practice sedation is often needed to perform diagnostic or minimally invasive procedures, minimize stress, and facilitate handling. The mortality rate of cats undergoing sedation is significantly higher than dogs, so it is fundamental that the sedatives provide good cardiovascular stability. Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist utilized in cats to provide sedation and analgesia, although studies have been utilized high doses, and markedly hemodynamic impairments were reported. The aim of this study was to prospectively investigate how the sedative and electrocardiographic effects of a low dose of DEX performing in cats. Eleven healthy cats were recruited; baseline sedative score, systolic arterial pressure, electrocardiography, and vasovagal tonus index (VVTI) were assessed, and repeated after ten minutes of DEX 5μg/kg intramuscularly (IM). A smooth sedation was noticed, and emesis and sialorrhea were common adverse effects, observed on average seven minutes after IM injection. Furthermore, electrocardiographic effects of a low dose of DEX mainly include decreases on heart rate, and increases on T-wave amplitude. The augmentation on VVTI and appearance of respiratory sinus arrhythmia, as well as sinus bradycardia in some cats, suggesting that DEX enhances parasympathetic tonus in healthy cats, and therefore will be best avoid in patients at risk for bradycardia.(AU)

Na rotina clínica da medicina veterinária felina a sedação é frequentemente requerida para realização de procedimentos diagnósticos ou minimamente invasivos, para minimizar o estresse e facilitar o manuseio dos pacientes. A taxa de mortalidade de gatos submetidos à sedação é mais elevada do que em cães, por esse motivo, é fundamental que os sedativos confiram estabilidade hemodinâmica. A dexmedetomidina (DEX) é um α2-agonista utilizado em felinos para promover sedação e analgesia, porém os estudos têm utilizado doses elevadas, e com isso prejuízos hemodinâmicos importantes foram relatados. O objetivo desta investigação foi avaliar os efeitos sedativos e eletrocardiográficos da baixa dose de DEX em gatos. Para tal, onze felinos saudáveis foram recrutados, foram obtidos valores basais para escore de sedação, pressão arterial sistólica e eletrocardiografia, além do índice de tônus vaso vagal (ITVV). Após dez minutos da aplicação intramuscular (IM) de DEX 5μg/kg todos os exames foram repetidos. Após a DEX, sedação suave foi detectada, e a êmese e sialorreia foram efeitos adversos comuns, observados em média 7 minutos após a injeção IM. Ademais, os principais efeitos eletrocardiográficos foram redução na frequência cardíaca e aumento na amplitude da onda T. O ITVV mais elevado e surgimento de arritmia sinusal respiratória, bem como bradicardia sinusal em alguns gatos, sugerem que a DEX eleva o tônus parassimpático, e por esse motivo deve ser utilizada com cautela em pacientes com predisposição à bradicardia.(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)

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...

Parámetros electrocardiográficos en gatos con pesos corporais distintos / Electrocardiographic values in cats with different body weights / Parâmetros eletrocardiográficos em gatos com pesos corporais distintos

Para la interpretación de los parámetros electrocardiográficos se utilizan valores estandarizados de amplitud y duración de las ondas electrocardiográficas de acuerdo con los patrones de normalidad descritos para y especie. Se sabe que en perros estos valores pueden variar de acuerdo con el peso y porte del animal, sin embargo, en gatos los valores estandarizados son genéricos y no toma en consideración esas características. Se evaluó con este estudio realizar una comparación entre los parámetros electrocardiográficos de gatos con pesos corporales distintos, a fin de verificar si hay variación en relación a los valores considerados estándar para la especie. Se evaluaron 64 gatos con el Índice de Condición Corporal (ICC) ideal y sin evidencia de ninguna enfermedad clínica. Después de la selección, los animales fueron divididos en dos grupos, siendo 25 gatos con peso igual o inferior 4 kg y 25 gatos con peso superior a 4 kg. Los valores electrocardiográficos fueron comparados entre los grupos por medio del test Mann-Whitney, con un 5% de significancia. Se realizó también un análisis descriptivo, comparando los valores encontrados con el patrón de normalidad para la especie establecido en la literatura. Se observó un aumento significativo del segmento PR en los gatos del grupo 2 y alteración del eje eléctrico cardíaco. Se concluye que el valor de PR es mayor en animales más pesados y los demás parámetros electrocardiográficos no varían entre gatos con peso igual o inferior a 4 kg y gatos con peso entre 4 a 6 Kg.(AU)

For the interpretation of the electrocardiographic parameters, standard values of amplitude and duration of the electrocardiographic waves are used, according to the normality patterns described for the species. These values may vary according to the weight and size of dogs, however, in cats the values are generic and do not take into account these characteristics. The aim of this study was to compare the electrocardiographic parameters of cats with different body weights in order to verify if there is variation in relation to the standard values considered for the species. Sixty-four cats with ideal body condition score (BCS) and no evidence of any clinical disease were evaluated. After selection, the animals were divided into two groups, 25 cats weighing 4 kg or less and 25 cats weighing more than 4 kg. The electrocardiographic values were compared between the groups by means of the Mann-Whitney test, with 5% significance. A descriptive analysis was also performed, comparing the values found with the standard of normality for the species established in the literature. A significant increase of the PR segment was observed in the cats of group 2 and alteration in the cardiac electrical axis. It is concluded that the value of PR is higher in heavier animals and the other electrocardiographic parameters do not vary between cats weighing 4 kg or less and cats weighing between 4 and 6 kg.(AU)

Para a interpretação dos parâmetros eletrocardiográficos são utilizados valores padronizados de amplitude e duração das ondas eletrocardiográficas de acordo com os padrões de normalidade descritos para e espécie. Sabe-se que em cães estes valores podem variar de acordo com o peso e porte do animal, entretanto, em gatos, os valores padronizados são genéricos e não levam em consideração essas características. Objetivou-se com este estudo realizar uma comparação entre os parâmetros eletrocardiográficos de gatos com pesos corporais distintos, a fim de verificar se há variação em relação aos valores considerados padrão para a espécie. Foram avaliados 64 gatos com escore de condição corporal (ECC) ideal e sem evidências de qualquer doença clínica. Após a seleção, os animais foram divididos em dois grupos, sendo 25 gatos com peso igual ou inferior 4 kg e 25 gatos com peso superior a 4 kg. Os valores eletrocardiográficos foram comparados entre os grupos por meio do teste Mann-Whitney, com 5% de significância. Foi realizada também uma análise descritiva, comparando os valores encontrados com o padrão de normalidade para a espécie estabelecido na literatura. Observou-se um aumento significativo do segmento PR nos gatos do grupo 2 e alteração do eixo elétrico cardíaco. Conclui-se que o valor de PR é maior em animais mais pesados e os demais parâmetros eletrocardiográficos não variam entre gatos com peso igual ou inferior a 4 kg e gatos com peso entre 4 a 6 Kg.(AU)

Parámetros electrocardiográficos en gatos con pesos corporais distintos / Electrocardiographic values in cats with different body weights / Parâmetros eletrocardiográficos em gatos com pesos corporais distintos

Para la interpretación de los parámetros electrocardiográficos se utilizan valores estandarizados de amplitud y duración de las ondas electrocardiográficas de acuerdo con los patrones de normalidad descritos para y especie. Se sabe que en perros estos valores pueden variar de acuerdo con el peso y porte del animal, sin embargo, en gatos los valores estandarizados son genéricos y no toma en consideración esas características. Se evaluó con este estudio realizar una comparación entre los parámetros electrocardiográficos de gatos con pesos corporales distintos, a fin de verificar si hay variación en relación a los valores considerados estándar para la especie. Se evaluaron 64 gatos con el Índice de Condición Corporal (ICC) ideal y sin evidencia de ninguna enfermedad clínica. Después de la selección, los animales fueron divididos en dos grupos, siendo 25 gatos con peso igual o inferior 4 kg y 25 gatos con peso superior a 4 kg. Los valores electrocardiográficos fueron comparados entre los grupos por medio del test Mann-Whitney, con un 5% de significancia. Se realizó también un análisis descriptivo, comparando los valores encontrados con el patrón de normalidad para la especie establecido en la literatura. Se observó un aumento significativo del segmento PR en los gatos del grupo 2 y alteración del eje eléctrico cardíaco. Se concluye que el valor de PR es mayor en animales más pesados y los demás parámetros electrocardiográficos no varían entre gatos con peso igual o inferior a 4 kg y gatos con peso entre 4 a 6 Kg.

For the interpretation of the electrocardiographic parameters, standard values of amplitude and duration of the electrocardiographic waves are used, according to the normality patterns described for the species. These values may vary according to the weight and size of dogs, however, in cats the values are generic and do not take into account these characteristics. The aim of this study was to compare the electrocardiographic parameters of cats with different body weights in order to verify if there is variation in relation to the standard values considered for the species. Sixty-four cats with ideal body condition score (BCS) and no evidence of any clinical disease were evaluated. After selection, the animals were divided into two groups, 25 cats weighing 4 kg or less and 25 cats weighing more than 4 kg. The electrocardiographic values were compared between the groups by means of the Mann-Whitney test, with 5% significance. A descriptive analysis was also performed, comparing the values found with the standard of normality for the species established in the literature. A significant increase of the PR segment was observed in the cats of group 2 and alteration in the cardiac electrical axis. It is concluded that the value of PR is higher in heavier animals and the other electrocardiographic parameters do not vary between cats weighing 4 kg or less and cats weighing between 4 and 6 kg.

Para a interpretação dos parâmetros eletrocardiográficos são utilizados valores padronizados de amplitude e duração das ondas eletrocardiográficas de acordo com os padrões de normalidade descritos para e espécie. Sabe-se que em cães estes valores podem variar de acordo com o peso e porte do animal, entretanto, em gatos, os valores padronizados são genéricos e não levam em consideração essas características. Objetivou-se com este estudo realizar uma comparação entre os parâmetros eletrocardiográficos de gatos com pesos corporais distintos, a fim de verificar se há variação em relação aos valores considerados padrão para a espécie. Foram avaliados 64 gatos com escore de condição corporal (ECC) ideal e sem evidências de qualquer doença clínica. Após a seleção, os animais foram divididos em dois grupos, sendo 25 gatos com peso igual ou inferior 4 kg e 25 gatos com peso superior a 4 kg. Os valores eletrocardiográficos foram comparados entre os grupos por meio do teste Mann-Whitney, com 5% de significância. Foi realizada também uma análise descritiva, comparando os valores encontrados com o padrão de normalidade para a espécie estabelecido na literatura. Observou-se um aumento significativo do segmento PR nos gatos do grupo 2 e alteração do eixo elétrico cardíaco. Conclui-se que o valor de PR é maior em animais mais pesados e os demais parâmetros eletrocardiográficos não variam entre gatos com peso igual ou inferior a 4 kg e gatos com peso entre 4 a 6 Kg.

Comparative Evaluation of the Echocardiographic Parameters of Dogs with Chronic Mitral Valve Regurgitation Treated with Amlodipine or Pimobendan

Background: Chronic mitral valve regurgitation is the most common heart disease in dogs. It is caused by myxomatous mitral valve degeneration, an acquired degenerative disease that can lead to congestive heart failure. Pimobendan is a mixed action drug, with inotropic and vasodilator proprieties, widely used to treat such dogs. Amlodipine is a pure vasodilator drug used as an anti-hypertensive agent, with no inotropic effects. This study aimed to compare  echocardiographic, electrocardiographic and blood pressure parameters between dogs with congestive heart failure treated with pimobendan and those treated with amlodipine in addition to conventional therapy.Materials, Methods & Results: A prospective, randomized, double-blind study was conducted in dogs with stage C chronic mitral valve regurgitation according to the 2009 American College of Veterinary Internal Medicine (ACVIM) guidelines, who weighed up to 15 kg. Randomization was performed using appropriate software and the sealed envelope technique. Blinding of the owner, the main researcher, and the person who performed the clinical analysis was guaranteed by the use of identical capsules and bottles for both pimobendan and amlodipine. Statistical analysis was performed using specialized software. Eligibility was determined by predefined inclusion and exclusion criteria. Dogs with cardiac disease other than mitral and/

Dogs poisoned with Nerium oleander fresh leaves: clinical and electrocardiographic findings / Cães intoxicados com folhas frescas de Nerium oleander: achados clínicos e eletrocardiográficos

Nerium oleander is distributed worldwide, mainly in tropical and subtropical regions. These shrubs are frequently used as ornamental plants. However, they contain more than 30 cardiac glycosides that can cause serious toxic effects in dogs. The objective of this study was to report the clinical and electrocardiographic alterations in dogs experimentally poisoned with N. oleander. Ten adult, healthy, mixed-breed dogs weighing 10-25kg and aged 3-6 years were selected for the study. We orally administered 0.25g kg-1 of fresh ground leaves of N. oleander to the dogs. No dog died after the ingestion, but all exhibited signs of poisoning such as vomiting, sialorrhea, nausea, apathy, conjunctiva congestion, dehydration, abdominal pain, tremors, diarrhea, loss of appetite, and tenesmus. Electrocardiogram revealed occurrence of several types of arrhythmias: sinus bradycardia, second-degree atrioventricular block, paroxysmal ventricular tachycardia, and ventricular premature complexes. Systolic blood pressure, as well as heart rate, decreased in the first 24 hours. The present study concluded that a single dose of 0.25g kg-1 of N. oleander green leaves is sufficient to cause a moderate intoxication in dogs, with nonspecific clinical changes mainly related to the digestive system and heart rate, thus demonstrating the importance of this type of intoxication in the list of differential diagnoses of small animals routine.

O Nerium oleander é uma planta com ampla distribuição mundial, principalmente em regiões tropicais e subtropicais. Esses arbustos são frequentemente usados como plantas ornamentais e possuem mais de 30 glicosídeos cardíacos causadores do quadro clínico de intoxicação em caninos. Sabendo-se disso, este artigo teve por objetivo a avaliar as alterações clínicas e eletrocardiográficas, nos animais intoxicados experimentalmente com N. oleander. Foram utilizados 10 cães adultos, hígidos, sem raça definida, com 10 a 25kg de peso, de 3 a 6 anos de idade. Os animais receberam uma única dose de 0,25g kg-1 de peso, de folhas frescas de N. oleander. Nenhum dos animais do experimento veio a óbito. Os sinais clínicos observados foram vômito, sialorréia, náuseas, apatia, conjuntiva ocular congesta, desidratação, dor abdominal, tremores, diarreia, inapetência e tenesmo. Pela análise do eletrocardiograma encontraram-se arritmias como: bradicardia sinusal, bloqueios atrioventriculares de segundo grau, taquicardia ventricular paroxística e complexo ventricular prematuro. A pressão arterial sistólica diminui nas primeiras 24 horas, assim como a frequência cardíaca. Concluiu-se com o presente estudo que uma única dose de 0,25g kg-1 de folhas verdes de N. oleander é suficiente para causar um quadro moderado de intoxicação em cães, com alterações clínicas inespecíficas principalmente relacionadas ao sistema digestório e no ritmo cardíaco, mostrando a importância deste tipo de intoxicação na lista de diagnósticos diferenciais da rotina de pequenos animais.

Dogs poisoned with Nerium oleander fresh leaves: clinical and electrocardiographic findings / Cães intoxicados com folhas frescas de Nerium oleander: achados clínicos e eletrocardiográficos

Nerium oleander is distributed worldwide, mainly in tropical and subtropical regions. These shrubs are frequently used as ornamental plants. However, they contain more than 30 cardiac glycosides that can cause serious toxic effects in dogs. The objective of this study was to report the clinical and electrocardiographic alterations in dogs experimentally poisoned with N. oleander. Ten adult, healthy, mixed-breed dogs weighing 10-25kg and aged 3-6 years were selected for the study. We orally administered 0.25g kg-1 of fresh ground leaves of N. oleander to the dogs. No dog died after the ingestion, but all exhibited signs of poisoning such as vomiting, sialorrhea, nausea, apathy, conjunctiva congestion, dehydration, abdominal pain, tremors, diarrhea, loss of appetite, and tenesmus. Electrocardiogram revealed occurrence of several types of arrhythmias: sinus bradycardia, second-degree atrioventricular block, paroxysmal ventricular tachycardia, and ventricular premature complexes. Systolic blood pressure, as well as heart rate, decreased in the first 24 hours. The present study concluded that a single dose of 0.25g kg-1 of N. oleander green leaves is sufficient to cause a moderate intoxication in dogs, with nonspecific clinical changes mainly related to the digestive system and heart rate, thus demonstrating the importance of this type of intoxication in the list of differential diagnoses of small animals routine.(AU)

O Nerium oleander é uma planta com ampla distribuição mundial, principalmente em regiões tropicais e subtropicais. Esses arbustos são frequentemente usados como plantas ornamentais e possuem mais de 30 glicosídeos cardíacos causadores do quadro clínico de intoxicação em caninos. Sabendo-se disso, este artigo teve por objetivo a avaliar as alterações clínicas e eletrocardiográficas, nos animais intoxicados experimentalmente com N. oleander. Foram utilizados 10 cães adultos, hígidos, sem raça definida, com 10 a 25kg de peso, de 3 a 6 anos de idade. Os animais receberam uma única dose de 0,25g kg-1 de peso, de folhas frescas de N. oleander. Nenhum dos animais do experimento veio a óbito. Os sinais clínicos observados foram vômito, sialorréia, náuseas, apatia, conjuntiva ocular congesta, desidratação, dor abdominal, tremores, diarreia, inapetência e tenesmo. Pela análise do eletrocardiograma encontraram-se arritmias como: bradicardia sinusal, bloqueios atrioventriculares de segundo grau, taquicardia ventricular paroxística e complexo ventricular prematuro. A pressão arterial sistólica diminui nas primeiras 24 horas, assim como a frequência cardíaca. Concluiu-se com o presente estudo que uma única dose de 0,25g kg-1 de folhas verdes de N. oleander é suficiente para causar um quadro moderado de intoxicação em cães, com alterações clínicas inespecíficas principalmente relacionadas ao sistema digestório e no ritmo cardíaco, mostrando a importância deste tipo de intoxicação na lista de diagnósticos diferenciais da rotina de pequenos animais.(AU)

Cardiorespiratory and electrocardiographic effects of methadone or morphine in the perioperative period in anesthetized dogs with continuous rate infusion of propofol and submitted to ovariohysterectomy / Efeitos cardiorrespiratórios e eletrocardiográficos da metadona ou morfina no período perioperatório em cães anestesiados com infusão contínua de propofol e submetidos a ovário-histerectomia

The aims of this study were compare the electrocardiogram (ECG) and cardiopulmonary effects of methadone or morphine, both injected intravenously (IV) in dogs anesthetized with continuous infusion of propofol. Sixteen healthy female mongrel dogs were used in this study for elective ovariohysterectomy. The animals were allocated in random order into two groups assigned GME (methadone 0.3 mg kg-1, IV) or GMO (morphine 0.3 mg kg-1, IV). Parameters were evaluated: heart rate (HR), P-wave amplitude (Ps and PmV), interval between Ps and R waves (PR), QRS duration (QRS), R-wave amplitude (R), duration the interval between the Q and T waves (QT), systolic blood pressure (SBP), rectal temperature (RT), respiratory rate (RR), end tidal of carbon dioxide (ETCO2 ) and periferic oxyhemoglobin saturation (SpO2 ). Postoperative analgesia was assessed by mechanical nociceptive stimulus based on the scale proposed by Firth and Haldane (1999) and rescue analgesia based on the visual analogue scale. HR was lower in GME in relation to GMO. The P, PmV, PR, QRS, R and QT values remained within their normality tracks, showing no clinical importance. Apnea and ETCO2 increased in both groups. There was no difference between groups of the analgesic effects. It can be concluded that methadone and morphine promote similar cardiovascular effects after IV injection during surgery in dogs anesthetized with propofol by continuous rate infusion, however, when methadone used, assisted ventilation is required. In addition, both drugs promote postoperative analgesia until six hours.(AU)

O presente estudo teve como objetivo comparar as alterações no eletrocardiograma (ECG) e nos parâmetros cardiorrespiratórios da metadona ou morfina administrada pela via intravenosa (I.V.) em cães anestesiados com infusão intravenosa contínua de propofol. Foram utilizados 16 cadelas, sem raça definida submetidos ao procedimento de ovário-histerectomia. Os animais foram distribuídos aleatoriamente em dois grupos, designados como GME (metadona 0,3 mg kg-1, I.V.) ou GMO (morfina 0,3 mg kg-1, I.V.). Os parâmetros avaliados foram frequência cardíaca (FC), tempo e amplitude da onda P (Ps e PmV), intervalo entre as ondas P e R (PR), duração do complexo QRS (QRS), amplitude da onda R (R), duração do intervalo entre as ondas Q e T (QT), pressão arterial sistólica (PAS), temperatura retal (TR), frequência respiratória (f), tensão de dióxido de carbono no final da expiração (ETCO2 ) e saturação de oxigênio na hemoglobina (SpO2 ). A analgesia pós-operatória foi verificada seguindo a proposta de Firth e Haldane (1999) e o regaste analgésico baseado na escala análoga visual. A FC foi menor no GME comparativamente ao GMO. Os valores de Ps, PmV, PR, QRS, R e QT mantiveram-se dentro da normalidade em ambos os grupos e sem significado clínico. Apneia e incremento da ETCO2 em ambos os grupos. Não houve diferença nos efeitos analgésicos entre os grupos. Podemos concluir que a metadona e a morfina promovem efeitos cardiovasculares similares quando administradas I.V. durante o procedimento cirúrgico em cães anestesiados com propofol via infusão continua intravenosa, no entanto, quando a metadona é empregada, ventilação assistida é necessária. Além disso, os dois opioides promoveram analgesia por 6h00 no pós-operatório.(AU)

Comparative evaluation of the echocardiographic parameters of dogs with chronic mitral valve regurgitation treated with amlodipine or pimobendan

Background: Chronic mitral valve regurgitation is the most common heart disease in dogs. It is caused by myxomatous mitral valve degeneration, an acquired degenerative disease that can lead to congestive heart failure. Pimobendan is a mixed action drug, with inotropic and vasodilator proprieties, widely used to treat such dogs. Amlodipine is a pure vasodilator drug used as an anti-hypertensive agent, with no inotropic effects. This study aimed to compare echocardiographic, electrocardiographic and blood pressure parameters between dogs with congestive heart failure treated with pimobendan and those treated with amlodipine in addition to conventional therapy. Materials, Methods & Results: A prospective, randomized, double-blind study was conducted in dogs with stage C chronic mitral valve regurgitation according to the 2009 American College of Veterinary Internal Medicine (ACVIM) guidelines, who weighed up to 15 kg. Randomization was performed using appropriate software and the sealed envelope technique. Blinding of the owner, the main researcher, and the person who performed the clinical analysis was guaranteed by the use of identical capsules and bottles for both pimobendan and amlodipine. Statistical analysis was performed using specialized software. Eligibility was determined by predefined inclusion and exclusion criteria. Dogs with cardiac disease other than mitral [...](AU)

Comparative evaluation of the echocardiographic parameters of dogs with chronic mitral valve regurgitation treated with amlodipine or pimobendan

Background: Chronic mitral valve regurgitation is the most common heart disease in dogs. It is caused by myxomatous mitral valve degeneration, an acquired degenerative disease that can lead to congestive heart failure. Pimobendan is a mixed action drug, with inotropic and vasodilator proprieties, widely used to treat such dogs. Amlodipine is a pure vasodilator drug used as an anti-hypertensive agent, with no inotropic effects. This study aimed to compare echocardiographic, electrocardiographic and blood pressure parameters between dogs with congestive heart failure treated with pimobendan and those treated with amlodipine in addition to conventional therapy. Materials, Methods & Results: A prospective, randomized, double-blind study was conducted in dogs with stage C chronic mitral valve regurgitation according to the 2009 American College of Veterinary Internal Medicine (ACVIM) guidelines, who weighed up to 15 kg. Randomization was performed using appropriate software and the sealed envelope technique. Blinding of the owner, the main researcher, and the person who performed the clinical analysis was guaranteed by the use of identical capsules and bottles for both pimobendan and amlodipine. Statistical analysis was performed using specialized software. Eligibility was determined by predefined inclusion and exclusion criteria. Dogs with cardiac disease other than mitral [...]

Effect of pregnancy and correlation of weight and heart rate with electrocardiographic parameters in the American Miniature Horse / Efeito da prenhez e correlação do peso e frequência cardíaca com os parâmetros eletrocardiográficos de equinos Mini-horse

There are studies on electrocardiogram (ECG) in several breeds of horses, which highlights the growing importance of cardiology in this species. But few authors have addressed the influence of pregnancy on the cardiac physiology of the mare, and specifically, there are no studies on the Mini-horse breed, as well as no correlation of body weight (BW) and heart rate (HR) with electrocardiographic parameters in this breed. The aims of this study were to determine the effects of pregnancy on ECG parameters and to examine the relationships between these variables and body weight (BW) and heart rate (HR). A total of 203 animals were used, including 143 females (66 pregnant) and 60 males. Electrocardiographic examinations were performed by computerized electrocardiogram (TEB), and the parameters were evaluated in six leads in the frontal plane (Lead I, II, III, aVR, aVL and aVF) and base-apex (BA). BW was inversely proportional to HR, which in turn showed an inverse relationship with the duration of the P-wave and the PR and QT intervals. The P-wave amplitude (lead II) was higher in pregnant animals than in non-pregnant animals. The effect of reproductive status should be monitored by ECG throughout the entire gestational period. The 66 pregnant mares in this study were examined during the first third of their pregnancies, thus, few differences were observed between pregnant and non-pregnant animals.(AU)

Existem estudos sobre eletrocardiograma (ECG) em diversas raças de equinos, o que ressalta a crescente relevância da cardiologia nessa espécie. Porém, poucos autores abordaram a influência da gestação na fisiologia cardíaca da égua, e, especificamente, não há trabalhos sobre a raça Mini-horse, assim como não há correlação do peso vivo (PV) e frequência cardíaca (FC) com os parâmetros eletrocardiográficos nessa raça. O objetivo deste estudo foi estudar a influência da prenhez sobre os parâmetros eletrocardiográficos, além de verificar a correlação do PV e FC com essas variáveis. Utilizaram-se 203 animais dessa raça, hígidos, sendo 143 fêmeas (66 prenhes) e 60 machos. Os exames eletrocardiográficos foram realizados por eletrocardiograma computadorizado (TEB), e os parâmetros foram avaliados em seis derivações do plano frontal (I, II, III, aVR, aVL e aVF) e base-ápice. O PV foi inversamente proporcional à FC, que também mostrou relação inversa com a duração da onda P e os intervalos PR e QT. Na derivação II, a amplitude da onda P foi maior nos animais prenhes do que vazios. No entanto, sugere-se que a influência do estado reprodutivo seja estudada de forma progressiva pelo acompanhamento de todo o período gestacional, visto que as 66 éguas estudadas se apresentavam no terço inicial da prenhez, portanto poucas diferenças foram observadas entre animais prenhes e vazios.(AU)

Effect of pregnancy and correlation of weight and heart rate with electrocardiographic parameters in the American Miniature Horse / Efeito da prenhez e correlação do peso e frequência cardíaca com os parâmetros eletrocardiográficos de equinos Mini-horse

There are studies on electrocardiogram (ECG) in several breeds of horses, which highlights the growing importance of cardiology in this species. But few authors have addressed the influence of pregnancy on the cardiac physiology of the mare, and specifically, there are no studies on the Mini-horse breed, as well as no correlation of body weight (BW) and heart rate (HR) with electrocardiographic parameters in this breed. The aims of this study were to determine the effects of pregnancy on ECG parameters and to examine the relationships between these variables and body weight (BW) and heart rate (HR). A total of 203 animals were used, including 143 females (66 pregnant) and 60 males. Electrocardiographic examinations were performed by computerized electrocardiogram (TEB), and the parameters were evaluated in six leads in the frontal plane (Lead I, II, III, aVR, aVL and aVF) and base-apex (BA). BW was inversely proportional to HR, which in turn showed an inverse relationship with the duration of the P-wave and the PR and QT intervals. The P-wave amplitude (lead II) was higher in pregnant animals than in non-pregnant animals. The effect of reproductive status should be monitored by ECG throughout the entire gestational period. The 66 pregnant mares in this study were examined during the first third of their pregnancies, thus, few differences were observed between pregnant and non-pregnant animals.(AU)

Existem estudos sobre eletrocardiograma (ECG) em diversas raças de equinos, o que ressalta a crescente relevância da cardiologia nessa espécie. Porém, poucos autores abordaram a influência da gestação na fisiologia cardíaca da égua, e, especificamente, não há trabalhos sobre a raça Mini-horse, assim como não há correlação do peso vivo (PV) e frequência cardíaca (FC) com os parâmetros eletrocardiográficos nessa raça. O objetivo deste estudo foi estudar a influência da prenhez sobre os parâmetros eletrocardiográficos, além de verificar a correlação do PV e FC com essas variáveis. Utilizaram-se 203 animais dessa raça, hígidos, sendo 143 fêmeas (66 prenhes) e 60 machos. Os exames eletrocardiográficos foram realizados por eletrocardiograma computadorizado (TEB), e os parâmetros foram avaliados em seis derivações do plano frontal (I, II, III, aVR, aVL e aVF) e base-ápice. O PV foi inversamente proporcional à FC, que também mostrou relação inversa com a duração da onda P e os intervalos PR e QT. Na derivação II, a amplitude da onda P foi maior nos animais prenhes do que vazios. No entanto, sugere-se que a influência do estado reprodutivo seja estudada de forma progressiva pelo acompanhamento de todo o período gestacional, visto que as 66 éguas estudadas se apresentavam no terço inicial da prenhez, portanto poucas diferenças foram observadas entre animais prenhes e vazios.(AU)