Columbianadin attenuates doxorubicin-induced cardiac injury, oxidative stress, and apoptosis via Sirt1/FOXO1 signaling pathway

Purpose: Oxidative stress and apoptosis contribute to the pathological basis of doxorubicin (DOX)-induced cardiotoxicity. Columbianadin (CBN) is one of the main bioactive constituents isolated from the root of Angelica pubescens. Herein, we intended to explore the potential role and molecular basis of CBN in DOX-induced cardiotoxicity. Methods: C57BL/6 mice were subjected to DOX (15 mg/kg/day, i.p.) to generate DOX-induced cardiotoxicity. CBN (10 mg/kg/day, i.p.) was administered for four week following DOX injection. Results: DOX administered markedly dampened cardiac function, increased cardiac injury, excessive reactive oxygen species (ROS) production, and cardiomyocyte loss. These alterations induced by DOX significantly alleviated by CBN treatment. Mechanistically, our results demonstrated that the CBN exerts cardioprotection role against DOX by up-regulating silent information regulator 1 (Sirt1) and decreasing acetylation of forkhead box O1 (FOXO1). Moreover, Sirt1 inhibition with Ex-527 significantly blunt the beneficial effect of CBN on DOX-induced cardiotoxicity, including cardiac dysfunction, ROS, and apoptosis. Conclusion: Collectively, CBN attenuated oxidative stress and cardiomyocyte apoptosis in DOX-induced cardiotoxicity through maintaining Sirt1/FOXO1 signaling pathway. Our results demonstrated that CBN might be used to treat DOX-related cardiotoxicity.

Sheep naturally infected with Anaplasma ovis - evaluation of cardiac and inflammatory biomarkers

Background: Anaplasmosis, also called gall sickness or tropical bovine ehrlichiosis, is an infectious disease caused by species belonging to the genus Anaplasma in domestic and wild animals in tropical and subtropical regions. Anaplasma ovis and A. phagocytophilum are important pathogens of sheep. A. ovis is considered the most common species affecting sheep. The infection is usually subclinical and progresses with high fever, anaemia, icterus, weight loss and abortions. This study aimed to investigate changes in cardiac damage markers, oxidative stress and antioxidant status, cytokines, and acute phase proteins in sheep naturally infected with A. ovis. Materials, Methods & Results: For this purpose, a total of 40 animals, including 20 healthy sheep and 20 sheep infected with anaplasmosis, were used. A. ovis was diagnosed based on clinical findings and peripheral blood smear. Blood smears were prepared from the ear vein. The smears were stained with Giemsa and examined for the presence of Anaplasma spp. Infection was also confirmed by polymerase chain reaction (PCR) analysis. The genomic DNA was isolated from blood, and the MSP-4 gene region was amplified as A. ovis specific target gene. Twenty clinically healthy sheep of the same age group, reared under the same conditions and testing negative in the molecular assessment were used as controls. Blood samples were collected from the cephalic vein and and centrifuged to obtain serum. The serum stored at -20°C until the analysis stage. Serum samples were used for the analysis of cardiac damage markers [troponin I (cTnI), creatine kinase MB (CK-MB), lactate dehydrogenase (LDH) and aspartate transaminase (AST)], oxidative stress parameters [malondialdehyde (MDA), total antioxidant status (TAS), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], cytokines [interleukins IL-6, IL-1ß and IL-10, tumour necrosis factor α (TNF-α), and interferon-γ (IFN-γ)] and acute phase proteins [C-reactive protein (CRP), serum amyloid A (SAA) and haptoglobin (Hp)]. cTnI and CK-MB levels were measured using a chemiluminescent immunoassay. MDA, TAS, SOD, CAT, GPx, TNF-α, IL-1ß, IL-6, IL-10, IFN-γ, SAA and Hp levels were measured by an ELISA reader. LDH, AST and CRP levels were measured in an autoanalyzer. cTnI and LDH levels were significantly increased in the infected animals compared to the healthy ones (P < 0.05). The concentration of AST was decreased in infected animals. MDA, TAS, SOD, CAT and GPx levels were significantly increased in the infected animals compared to the healthy ones (P < 0.05). The levels of the inflammatory parameters such as TNF-α, IL-1ß, IL-10 and IFN-γ were significantly increased in the infected animals compared to the healthy ones (P < 0.05). Hp level were significantly increased in the infected group compared with the control group (P < 0.05). However, there was no significant change in CK-MB, SAA and CRP concentrations in the infected animals (P > 0.05). Discussion: Ovine anaplasmosis is an obligate intracellular arthropod disease that causes widespread changes in haematobiochemical, immune response and oxidative stress parameters. Cardiac damage is often overlooked in field conditions due to the lack of adequate knowledge about the pathophysiology of the disease. Our results showed that A. ovis infection leads to significant changes in cardiac biomarkers and that the parasite can cause cardiac dysfunction. This is the first report on cardiac damage markers in Anaplasma-infected sheep. Additionally, the levels of proinflammatory and oxidative stress markers that may cause functional disorders were also found to be increased. Thus, measuring markers of cardiac function, oxidative stress and inflammation can be a useful tool in the early diagnosis of ovine anaplasmosis.

Interatrial septal aneurysm associated with patent foramen ovale in a dog - case report / Aneurisma de septo interatrial associado a forame oval patente em cão - relato de caso

Atrial septal aneurysm (ASA) is a rare congenital deformity of variable clinical relevance, often reported in association with patent foramen ovale (PFO). Transthoracic Doppler echocardiography (TTE) is the first choice for diagnosis, but complementary techniques, such as microbubble contrast, should be used. Despite its importance, in Veterinary Medicine, there is little information related to the subject, and the present study is the second report of this condition in dogs. The objective was to report a case of ASA type IV LR associated with PFO in a Shar Pei bitch, diagnosed by a combined approach of transthoracic echocardiography backed by agitated saline solution (microbubbles). During clinical care, the owners reported episodes of seizures as their main complaint. Echocardiographic examination revealed a type 4 LR atrial septal aneurysm and left ventricular systolic dysfunction. The use of microbubble contrast showed right-to-left shunt, confirming PFO. The recommended treatment was medication. It was concluded that the rarity of ASA in dogs may be due to incomplete diagnoses and the transthoracic echocardiographic examination allows its analysis and classification. Furthermore, ASA can be found in animals with or without evidence of heart disease and it should be investigated in patients with neurological alterations.

O aneurisma do septo atrial (ASA) é uma rara deformidade congênita, de relevância clínica variável, frequentemente relatado em associação a forame oval patente (PFO). O ecodopplercardiograma transtorácico (TTE) é a primeira escolha para o diagnóstico, mas técnicas complementares, como o contraste por microbolhas, devem ser utilizadas. Apesar da importância, em medicina veterinária existe uma carência de informações relacionadas ao tema, sendo esse o segundo relato dessa condição em cão. Objetivou-se relatar um caso de ASA tipo IV LR, associado a PFO, em uma cadela Shar Pei, diagnosticado por uma abordagem combinada por ecodopplercardiograma transtorácico e costrastado com solução salina agitada (microbolhas). Ao atendimento clínico, os proprietários relataram, como queixa principal, episódios de crises convulsivas. O exame ecocardiográfico revelou aneurisma de septo atrial tipo 4 LR e disfunção sistólica em ventriculo esquerdo. A utilização de contraste por microbolhas constatou shunt direita-esquerda, confirmando PFO. O tratamento recomendado foi medicamentoso. Concluiu-se que a raridade do ASA em cães pode ser devido a diagnósticos incompletos, e o exame ecocardiográfico transtorácico permite sua análise e classificação. Ainda, ASA pode ser encontrado em animais com ou sem evidências de cardiopatia e sua investigação deve ser feita em pacientes com alterações neurológicas.

Hypertrophic phenotypic cardiomyopathy in an ocelot (Leopardus pardalis)

Background: Hypertrophic cardiomyopathy phenotype (HCM) is the most common cardiac disease in domestic cats but is rarely described in wild species. This phenotype is characterized by concentric hypertrophy of the left ventricle and may be of familial inheritance or secondary to other diseases such as hyperthyroidism, chronic kidney disease, systemic arterial hypertension, and hyperaldosteronism. HCM can cause diastolic and systolic dysfunction and may cause congestive heart failure in affected animals. The present work aims to describe the first report of cardiomyopathy of the hypertrophic phenotype in a specimen of Leopardus pardalis, kept under human care. Case: A 11-year-old female ocelot (Leopardus pardalis) kept under human care, during a preventive care visit, had hypertrophic cardiomyopathy phenotype detected by cardiological evaluation with echocardiogram and a murmur grade III/ VI could be detected on cardiac auscultation. This preventive care occurred under chemical restraint with ketamine [6 mg/kg, i.m] associates with midazolam [0.5 mg/kg, i.m] and other evaluations have been done like complete blood count (CBC), biochemistry (alanine aminotransferase, aspartate aminotransferase, total proteins, albumin, albumin:globulin ratio, creatinine, urea, sodium, potassium, calcium, phosphorus, and globulin) and tyroid hormones [free tyroxine (T4) and thyroid-stimulating hormone (TSH)]. Medical management based on clopidogrel, and atenolol was administered for 3 months until the patient showed manifestations of congestive heart failure (CHF) 80 days later the initial evaluation. In this moment the patient presented with dyspnea, so a cardiological and laboratory evaluation was requested. On pulmonary auscultation crackling was identified, suggesting pulmonary edema and, on echocardiographic examination, some parameters had worsened. The CBC and biochemistry were all within reference ranges. Then, the beta-blocker was discontinued and replaced by pimobendan combined with furosemide as treatment of CHF, and the condition stabilized. After one year, the patient was re-evaluated and showed a slight improvement in the condition but still remained stable. Also, feline proBNP levels was tested (SNAP Feline proBNP® IDEXX) in this moment and it was increased. Discussion: The findings on echocardiography associated with the subjective evaluation associated with progressive worsening and clinical manifestation of CHF, as well as the response to treatment, even though there are no reference values for the species, reinforce the diagnosis. There is no evidence to suggest diseases that may contribute to secondary left ventricular hypertrophy. It is believed that pimobendan plays a key role in maintaining hemodynamic balance, since this has already been observed in other mammalian species. The use of beta blockers is commonly employed in domestic cats with HCM, and they have been prescribed in an attempt to promote greater ventricular relaxation, decrease left ventricular outflow obstruction, thus improving ventricular filling for maintenance of cardiac output. In view of the atrial enlargement and possible risk of thrombus formation, clopidogrel was prescribed, extrapolating what is known from domestic cats. It is reasonable to conclude that in this case, the cardiomyopathy behaved similarly to what is observed in domestic cats, both in its clinical evolution and in the means of diagnosis, and in its response to the therapy instituted.

Eletrocardiografia basal e após exercício em cães braquicefálicos / Baseline and post exercise electrocardiography in brachycephalic dogs

Background: The brachycephalic dog breeds have been increasing in Brazil, and these animals are predisposed to present the brachycephalic dog syndrome, consisting of anatomical defects that lead to physiological changes and clinical signs such as wheezing, dyspnea, and hypoxia. Electrocardiography (ECG) is a simple test that can detect disturbances in the electrical activity of the heart, including changes present in hypoxia. The brachycephalic dog syndrome can lead to pulmonary hypertension due to hypoxia. Based on this, the present work aimed to evaluate the ECG of brachycephalic dogs in search of significant changes in heart rhythm, ECG waves, and cardiac axis. Materials, Methods & Results: Twenty-nine dogs were evaluated in this study, 19 brachycephalic and 10 mesaticephalic, after approval by an ethics committee the animals were selected. Electrocardiographic examinations were performed in 2 stages, at rest and immediately after a 3-min trot. The exam was performed with a computerized electrocardiograph, with a standard time of 5 min. The standard positioning for performing the examination was the right lateral decubitus position. To improve the electrical conductivity, 70% alcohol was used between the animal's skin and the electrodes. In statistical analysis, paired t test was performed for comparison of the same group before and after exercise and unpaired t test between groups at the same moments, considering P < 0.05 as significant. Nineteen brachycephalic animals were evaluated, 10 Pugs and 9 French Bulldogs, 9 males and 10 females. The mean age was 3.4 ± 1.8 years; and the mean weight was 12.5 kg ± 2.7 kg. In the control group, consisting of ten mesaticephalic animals, all were non-breed, three males and seven females; the mean age and weight in this group were 4.4 ± 1.5 years and 7.5 kg ± 0.5 kg, respectively. There was a significant increase in heart rate (bpm) after exercise in brachycephalic dogs (baseline: 119.3 ± 4.3; after exercise: 135.1 ± 4.9; P = 0.0005). The same occurred for P wave amplitude (mV) (baseline: 0.20 ± 0.01; after exercise: 0.22 ± 0.01; P = 0.0001). These differences were not found in the control group. There were no alterations in the duration of the P wave, PR interval, QRS complex, and QT interval, and all were within normal values for the species in both groups. The R-wave amplitude remained unaltered and within normal values in both the control and brachycephalic groups. Discussion: The elevation in heart rate may be associated with the chemoreflex secondary to the increased demand for oxygenation during exercise and the hypoxia generated by it. The increase in P amplitude suggests right atrial overload. The P wave corresponds to the atrial depolarization and its amplitude corresponds to the electrical activity in the right atrium. Thus, it is possible to relate the increase in P amplitude and heart rate to the hypoxia caused by exercise in brachycephalic, since this hypoxia results in chemoreceptor activation that increases chronotropism and heart rate. Also, there may be increased pressure in the pulmonary trunk, this increased pressure occurs due to vasoconstriction generated as a reflex to hypoxia in the pulmonary alveoli, leading to a possible picture of acute pulmonary hypertension that, in a cascade effect, leads to hypertrophy and dilation of the right ventricle, increased strength of contractility and ejection affecting the tricuspid valve causing a reflux and consequent overload of the right atrium.

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)

Anasarca associated with restrictive cardiomyopathy in cats

Background: Cardiomyopathies are a primary heart disorder and are one of the most causes of heart failure and sudden death in cats. Restrictive cardiomyopathy is a diastolic dysfunction resulting from endomyocardial fibrosis, with filling restriction and ventricular distention. In these cases, a poor outcome is expected. Anasarca in animals is often associated with dystocia secondary to congenital changes. In adults, this is a rare condition, since subcutaneous edema in animals with congestive heart failure is an uncommon finding. Therefore, this report describes clinical and pathological findings in an unusual presentation of anasarca in two adult cats with restrictive cardiomyopathy. Cases: A 12-year-old female mixed breed cat (case 1) and a 6-year-old male mixed-breed cat (case 2) were present on an emergent basis at the veterinary hospital with a history of respiratory distress. Case 1 showed on physical examination intense restrictive mixed dyspnea and lethargy, with muffled heart sounds and respiratory noises in cardiorespiratory auscultation. The cat exhibited abdominal distension resulting from ascites. Generalized subcutaneous edema was evident mainly in the abdominal and submandibular areas and the thoracic and pelvic limbs. In these regions, a positive Godet signal was observed. Thoracic radiography revealed pleural effusion, and the cat underwent fluid drainage on both sides of the thoracic cavity. Drainage material was sent to the laboratory for clinical analysis, which indicated that it was a modified transudate. The clinical signs worsened, and the cat was euthanized. In case 2, physical examination showed severe restrictive mixed dyspnea, lethargy, and low body temperature (< 32°C). Abdominal distension resulting from ascites and generalized edema in the subcutaneous tissue with a positive Godet sign was observed. On cardiorespiratory auscultation, cardiac sounds and breathing noises were muffled. Thoracic radiography revealed pleural effusion. The cat was immediately placed in an incubator for clinical stabilization with oxygen therapy and warm-up. After 2 h of hospitalization, thoracentesis and drainage of cavity fluids were performed, which were classified as modified transudate. The patient remained in critical condition during hospitalization, evolving to death. The two cats were referred for a complete post mortem examination. Grossly, both cats showed distension of the abdomen and marked edema of subcutaneous tissue, mainly in the abdominal, ventral cervical, and thoracic and pelvic members. In the abdominal and thoracic cavities, a moderate amount of serous-free liquid, slightly reddish was observed. The heart of both cats was enlarged, with a globose appearance and a slightly whitish epicardium. The left ventricular endocardium was mild and diffusely thick and whitish, in addition to moderate dilation of the left atrium. Histological analyses of the heart showed in both cats moderate and diffuse proliferation of fibrous connective tissue in the endocardial region. Discussion: Restrictive cardiomyopathy has major importance in feline medicine due to its severity and poor outcome. Pleural effusion, pulmonary edema, and ascites are common findings in cats with congestive heart failure; however, generalized subcutaneous edema is uncommon. To the author's knowledge, there are no published cases in the literature of anasarca in adult cats with restrictive cardiomyopathy. In human cardiology, this presentation is commonly related to congestive heart failure, and it is reported under several conditions, such as restrictive cardiomyopathy and constrictive pericarditis. The present study suggests that anasarca should be included in the list of associated clinical signs suggestive of severe congestive heart failure, mainly related to restrictive cardiomyopathy.

Unilateral atrial ectopic rhythm in a golden retriever

Background: Atrial ectopic rhythm is a type of supraventricular arrhythmia, originating in two distinct points in the atrialregion. In the electrocardiographic (ECG) tracing, it is represented by independent depolarizations of sinus P waves andectopic P waves. The occurrence of this disorder is rare, and the diagnosis criteria are the presence of the described waveswithin the basal rhythm. In humans, there have been reports related to severe heart failure with an unfavorable prognosis.The present report aimed to describe the clinical case of a dog with unilateral atrial ectopic rhythm without any underlying cardiac disorder.Case: A 8-year-old male golden retriever was brought to a veterinary clinic for a preoperative evaluation for lipoma removalin the right forelimb. On clinical examination, the owner stated that the patient was active, with no signs of easy fatigueor cough. The canine displayed normophagy, normodipsia, normoquezia, and normouria. On physical examination, hedemonstrated a lymphatic temperament with tachypnea. The temperature and capillary filling time were within the normalrange, with a normokinetic pulse. Cardiac auscultation revealed a mild grade I/VI murmur in mitral focus and an 80-bpmheart rate. Respiratory auscultation revealed the presence of harshy lung sounds. The cough reflex was positive; the Piparotetest, negative. The blood test showed no noticeable changes in blood count and serum biochemistry. Systemic systolicblood pressure was 120 mmHg. On radiographic examination, no evidence of heart or lung abnormalities were identified.After the clinical evaluation, an ECG examination was performed; a unilateral atrial ectopic rhythm was observed withdifferent frequencies between atrial and ventricular rhythm and with P (164°) and P waves (80°). On echocardiographic...

Unilateral atrial ectopic rhythm in a golden retriever

Background: Atrial ectopic rhythm is a type of supraventricular arrhythmia, originating in two distinct points in the atrialregion. In the electrocardiographic (ECG) tracing, it is represented by independent depolarizations of sinus P waves andectopic P waves. The occurrence of this disorder is rare, and the diagnosis criteria are the presence of the described waveswithin the basal rhythm. In humans, there have been reports related to severe heart failure with an unfavorable prognosis.The present report aimed to describe the clinical case of a dog with unilateral atrial ectopic rhythm without any underlying cardiac disorder.Case: A 8-year-old male golden retriever was brought to a veterinary clinic for a preoperative evaluation for lipoma removalin the right forelimb. On clinical examination, the owner stated that the patient was active, with no signs of easy fatigueor cough. The canine displayed normophagy, normodipsia, normoquezia, and normouria. On physical examination, hedemonstrated a lymphatic temperament with tachypnea. The temperature and capillary filling time were within the normalrange, with a normokinetic pulse. Cardiac auscultation revealed a mild grade I/VI murmur in mitral focus and an 80-bpmheart rate. Respiratory auscultation revealed the presence of harshy lung sounds. The cough reflex was positive; the Piparotetest, negative. The blood test showed no noticeable changes in blood count and serum biochemistry. Systemic systolicblood pressure was 120 mmHg. On radiographic examination, no evidence of heart or lung abnormalities were identified.After the clinical evaluation, an ECG examination was performed; a unilateral atrial ectopic rhythm was observed withdifferent frequencies between atrial and ventricular rhythm and with P (164°) and P waves (80°). On echocardiographic...(AU)

Electrocardiographic, echocardiographic and heart biomarker parameters in sheep experimentally poisoned by Palicourea marcgravii (Rubiaceae) / Parâmetros eletrocardiográficos, ecocardiográficos e de biomarcadores cardíacos em ovinos intoxicados experimentalmente por Palicourea marcgravii (Rubiaceae)

The present study aimed to identify and describe cardiac alterations in sheep experimentally poisoned with Palicourea marcgravii through analysis of serum cardiac biomarkers (serum troponin I and creatine kinase - CK-MB) and electro and echocardiographic assessments to contribute to a better understanding of the poisoning pathophysiology. P. marcgravii is the main plant within a group of 22 species that cause sudden death in Brazil; its toxic principle is sodium monofluoroacetate. Eight healthy crossbreed male sheep, aged between five and twelve months, weighing 14 to 27kg, were evaluated. The animals received 1g kg-1 of P. marcgravii plants orally. The sheep were evaluated before administering the plant (T0) through electro and echocardiography and blood collection to assess cardiac biomarkers (CK-MB and cTnI). Collections and analyses were repeated every four hours until the animal's death. During the study, there was the presence of extravasation of serum troponin I carried out in a qualitative test, with positive values at time T4, and the serum CK-MB biomarker had a peak at T4 and slightly decreased at T8. The electro and echocardiographic examinations showed that the cause of death in these animals was due to acute heart failure characterized by arrhythmias, tachycardia/ventricular fibrillation, drop in cardiac output, left ventricular (LV) systolic dysfunction by the progressive decrease in the LV ejection fraction (EF), decrease in LV fractional shortening (FS), and decrease in aortic flow velocity and aortic flow gradient. This study seems to be the first to evaluate cardiac alterations in sheep poisoned by P. marcgravii through cardiac biomarkers and electro and echocardiographic exams.

O presente estudo objetivou identificar e descrever as alterações cardíacas de ovinos intoxicados experimentalmente por Palicourea marcgravii através das análises de biomarcadores cardíacos séricos (troponina I sérica e a creatinoquinase - MB) e das avaliações eletro e ecocardiográficas contribuindo para o melhor entendimento da fisiopatologia da intoxicação. Palicourea marcgravii é a principal planta dentro de um grupo de 22 espécies que causam "morte súbita" no Brasil e seu princípio tóxico é o monofluoracetato de sódio. Foram utilizados oito ovinos saudáveis machos, sem raça definida, com idades entre cinco e doze meses e peso de 14 a 27kg. Os animais receberam 1g/kg de Palicourea marcgravii por via oral. Os ovinos foram avaliados momentos antes da administração da planta (T0) através de eletro e ecocardiograma e coleta de sangue para avaliação dos biomarcadores cardíacos (CK-MB e cTnI). As análises e coletas foram repetidas a cada quatro horas até o óbito do animal. Durante o estudo observou-se extravasamento de troponina I sérica realizada em teste qualitativo, com valores positivos já em T4, assim como o biomarcador CK-MB sérico teve seu pico de aumento em T4 e em T8 houve uma leve redução. Aos exames eletro e ecocardiográfico foi possível determinar que a causa do óbito nestes animais ocorreu devido à insuficiência cardíaca aguda caracterizada por arritmias, taquicardia/fibrilação ventricular, queda no débito cardíaco, disfunção sistólica do ventrículo esquerdo (VE) pela diminuição progressiva da fração de ejeção (EF) do VE, diminuição na fração de encurtamento (FS) do VE, diminuição da velocidade do fluxo aórtico e do gradiente do fluxo aórtico. Este é o primeiro estudo que avalia as alterações cardiológicas de ovinos intoxicados por P. marcgravii através de biomarcadores cardíacos e exames eletro e ecocardiográficos.

Marek's disease in roosters in the Potiguar semi-arid region

Background: Marek's disease (MD) is a transmissible disease in chickens caused by Gallid alphaherpesvirus 2 (GaHV-2). The infection is characterized by lymphocyte cellular infiltrates in peripheral nerves and other organs and tissues, including the skin; which can lead to dysfunction causing progressive asymmetric paresis and complete spastic paralysis of body extremities. Dermatitis and cardiac myositis caused by GaHV-2 in free-range chickens has rarely been described in Brazil. This reports the occurrence of the disease with a confirmatory molecular diagnosis in free-range poultry showing signs of dermatitis, poor performance, and cachexia and no mortality in the semi-arid Potiguar region. Cases: Twenty roosters of the Shamo lineage, among a brood of 42 birds, had a history of progressive weight loss and skin lesions. Two birds with poor body condition, erythema, and scaling of the skin in the head and cervical regions were sent for clinical care. All birds were between 12 and 18 months of age and were vaccinated against Newcastle disease and Fowlpox with only a few receiving vaccines against MD and Gumboro disease. According to the owner's report, some birds were previously kept outdoors, and when they were transferred to a small shed with little air circulation, they began to develop clinical signs after approximately 15 days. The first signs of the disease were also reported to have appeared 2.5 months before clinical care and, in the meantime, several treatments were instituted without success. Owing to the general condition of the animals and inconclusive clinical suspicion, the birds were subjected to euthanasia and necropsy. Tissue samples were collected for histopathological and polymerase chain reaction analyses to search for the GaHV-2 DNA meq gene. The main clinicopathological findings were erythema (47%, 20/42) and desquamation of skin and mild, prominent white multifocal areas in the heart. Histopathology revealed infiltration of pleomorphic lymphoblastic cells in the skin, heart, and sciatic nerve. The amplification of the L-meq and meq oncoprotein genes in these organs and in the liver, confirmed the infection by GaHV-2, consistent with that of a field strain. Discussion: MD was confirmed based on the macroscopic and histological lesions, and with the detection of GaHV-2 DNA in the affected tissues. The unusual clinical presentation represented an initial challenge for diagnosis. The clinical history was important to lead to the suspicion of MD, as roosters initiated clinical signs 15 days after they were transferred to a small shed with poor air circulation. This probably favored the high viral concentration and disease transmission among susceptible birds in the brood because the feather follicle is the primary site of viral replication for transmission; and desquamation of infected epithelial cells favor airborne horizontal transmission to susceptible chickens. The roosters had not been vaccinated against MD, which probably favored the infection, as vaccination is known to be a fundamental approach for MD control for effective growth of the poultry industry. Clinical findings and lesions, together with viral molecular detection, were fundamental for the diagnosis, a premise for the application of adequate prevention and control measures for the disease in breeding. This is the first report of MD with a confirmatory molecular diagnosis in northeastern Brazil.

Artéria subclávia direita aberrante em cão - aspectos clínicos e de imagem / Aberrant right subclavian artery in a dog - clinical and imaging aspects

Background: Aberrant right subclavian artery is only rarely observed in veterinary medicine. Some animals may present postprandial regurgitation and progressive weight loss, which is considered an incidental finding unrelated to clinical alterations. Advanced imaging techniques such as thoracic CT scan, magnetic resonance imaging (MRI) and contrast angiography are used for the accurate detection of lesions, anatomical changes and specific information about vascular rings. This paper describes the clinical changes, imaging exams and therapeutic approach in a female dog with megaesophagus induced by an aberrant right subclavian artery. Case: A 2-month-old female bull terrier, weighing 1.6 kg, with a history of regurgitation immediately or a few minutes after a meal, diarrhea, polyphagia, progressive emaciation and apathy for 45 days, was treated at a University Veterinary Hospital. The dog's physical examination revealed 7% dehydration and body condition score 1 (scale 1 to 5), but no cardiac or pulmonary alterations upon auscultation. The hematological analysis and renal and hepatic serum enzymes were within the normal range for the species. In view of the presumptive clinical diagnosis of vascular anomaly, suggested by the contrast X-ray examination, a chest tomography was performed, which revealed altered aortic arch shape and contours, and a posterior aneurysm in the area of abnormal connection of the right subclavian artery. The patient was released with a prescription for conservative dietary management for megaesophagus. Within two weeks, the patient returned with a report of a good response to the prescribed therapy, absence of vomiting and diarrhea, and an increase in body weight. Surgical correction was recommended, but has not been performed so far, but conservative treatment for megaesophagus was continued. No further episodes of regurgitation were identified during the nine-month follow-up period. Discussion: In the case reported here, the right subclavian artery is considered anatomically atypical because it arises directly from the aortic arch. This vascular anomaly passes on to the right pectoral limb, dorsal to the esophagus, contracting it in its dorsal aspect. It tends to affect purebred dogs, occurring more frequently in Irish setters, German shepherds and Labrador retrievers, although it has been described in other breeds such as the bull terrier documented here and mixed breed dogs. Vascular ring anomalies may not cause clinical changes in animals and represent only incidental findings, or they may lead to gastrointestinal changes resulting from esophageal stricture, contributing to megaesophagus and clinical signs of esophageal obstruction, especially in recently weaned puppies. Such alterations were observed in this case, with the dog presenting regurgitation, immediately or a few minutes after a meal, megaesophagus, diarrhea and progressive weight loss. A CT scan was performed to confirm the type and location of the vascular anomaly and diagnostic accuracy, as recommended in the literature. Dietary therapy is one of the approaches adopted for patients presenting with regurgitation resulting from megaesophagus secondary to vascular anomalies. The dog in this report responded well to the medical therapy; nevertheless, the treatment of choice to correct the esophageal obstruction caused by this anomaly is surgical sectioning of the aberrant vessel by right intercostal thoracotomy, given that the degree of esophageal dilation and dysfunction tends to increase over time. However, at this time, the animal's owner decided to suspend the recommended surgical procedure.

Tamponamento cardíaco secundário ao hemangiossarcoma em cães / Cardiac tamponade secondary to hemangiosarcoma in a dog

Background: Nonspecific clinical manifestations such as apathy, anorexia and diarrhea are common in the clinical routine, and therefore may mask the severity of its triggering factor. When patients presenting this symptomatology are referred to the care center, it is essential that a thorough investigation is performed to clarify the primary causes of these manifestations, and for this, complementary imaging exams may be necessary. The objective of this study is to describe the clinical and imaging aspects of a canine with cardiac hemangiosarcoma and to correlate with the pathophysiology of the alterations observed, in order to optimize the clinical care of patients with nonspecific clinical signs and affected by this alteration. Case: A 10-year-old Pitbull dog was treated with a history of vomiting, loss of appetite and diarrhea. Upon clinical examination, the animal presented dehydration level and distended abdomen. On ultrasound examination, hepatomegaly was observed, associated with signs of double layer in the gallbladder wall and the presence of moderate peritoneal effusion. On chest radiography, the cardiac silhouette showed an important increase in size with loss of shape and contours. Dorsal displacement of the trachea, greater contact of the heart with the sternum and displacement of the caudal vena cava were observed. In addition, an amorphous and poorly defined structure with radiopacity of soft tissues was observed in the region of the atrium and right ventricle, causing the obliteration of pulmonary fields. On echocardiographic examination, a significant amount of free anechogenic fluid was observed in the pericardial sac, confirming the suspicion of pericardial effusion, with consequent collapse of the wall of the right heart chambers during systole. Furthermore, an amorphous, poorly defined and heterogeneous structure was observed in the right atrium wall. Due to the location of the neoformation, the patient's general clinical condition, euthanasia was chosen. During the necropsy, the ocular, oral and preputial mucosae were moderately pale. In the abdomen, the presence of hydroperitoneum and hepatomegaly was observed. In the thoracic cavity, hemothorax, enlarged heart were identified and, in the right atrium, a reddish mass was identified. In addition, the lungs were whitish and hypercrepitating at the edges of the cranial lobes; the rest of the organ was moderately hyperemic, hypocrepitating. In histopathological examination of the liver, the centrilobular region showed chronic passive congestion associated with necrosis and multifocal degeneration of hepatocytes. Neoplastic proliferation of mesenchymal cells, moderately cellular, non-encapsulated, of infiltrative growth was observed in the heart. Neoplastic cells formed bundles, with a tendency to organize themselves into small blood vessels filled with red blood cells. The cytoplasm was moderate, elongated, indistinct, eosinophilic and homogeneous. The nucleus was large, unique, elongated, with finely dotted chromatin and sometimes with one or two nucleoli evident. Anisocytosis, anisocariosis and cell pleomorphism were moderate. Interwoven with neoplastic cells, a moderate presence of multifocal lymphohistioplasmocytic inflammatory infiltrate was observed. The definitive diagnosis of cardiac changes was hemangiosarcoma. Discussion: Hemangiosarcoma is a vascular endothelial cell neoplasm with high metastatic power and unfavorable prognosis. When located in the heart, it is commonly found in the auricle and right atrium and the cardiovascular changes caused by this neoplasm as well as the severity of these changes vary according to size and location. Clinical manifestations can be quite nonspecific and are usually associated with hemodynamic impairment, causing signs of right or left congestive heart failure.

Congestive heart failure in a young cat with excessive moderator bands (false tendons) in the left ventricle / Insuficiência cardíaca congestiva em um gato jovem com bandas moderadoras excessivas (falsos tendões) em ventrículo esquerdo

Left ventricular false tendons are fibrous or fibromuscular bands that transverse the ventricular cavity and have no attachment to the mitral valve in many species. In cats it is considered a congenital defect that is rarely related to clinical disease and death in adult cats. A 45 days-old mixed breed cat had a history of inappetence since birth. At the physical exam the patient was lethargic and presented restrictive dyspnoea. At necropsy, there were marked ascites, hydrothorax, hepatomegaly with enhanced lobular pattern (nutmeg liver), and the lungs were markedly diminished (compressive pulmonary atelectasis). The heart was enlarged due to marked dilation of the cardiac chambers. Moreover, multiple slightly whitish and irregular cord-like structures were connecting the posterior papillary muscle to the interventricular septum (excessive moderator bands /left ventricular false tendons) at the left ventricle. Microscopically, these structures were characterized by a marked proliferation of fibrous connective tissue intermixed with Purkinje cells and well-differentiated cardiomyocytes lined by a single layer of endocardium. This study described a case of excessive moderator bands (left ventricular false tendons) in a young cat associated with congestive heart failure and death.

Falsos tendões são bandas fibrosas ou fibromusculares que atravessam a cavidade do ventrículo esquerdo, sem ligação com a valva mitral, em várias espécies. Nos gatos, a alteração é considerada um defeito congênito que raramente está relacionada com alterações clínicas e morte em gatos adultos. Um gato de 45 dias de idade, sem raça definida e com histórico de inapetência desde o nascimento foi encaminhado para atendimento veterinário. Ao exame físico apresentou letargia e dispneia restritiva. À necropsia, havia acentuada ascite, hidrotórax, hepatomegalia com evidenciação do padrão lobular (fígado noz-moscada) e os pulmões apresentavam-se acentuadamente diminuídos (atelectasia pulmonar compressiva). O coração apresentava acentuada dilatação das câmaras cardíacas. Em ventrículo esquerdo, havia numerosas estruturas brancacentas semelhantes a cordas conectando o músculo papilar ao septo interventricular (bandas moderadoras excessivas/falsos tendões). Microscopicamente, estas estruturas apresentavam acentuada proliferação de tecido conjuntivo fibroso, além de células de Purkinje e cardiomiócitos bem diferenciadas revestidas por uma única camada de endocárdio. O objetivo deste trabalho é descrever um caso de bandas moderadoras excessivas (falsos tendões) em ventrículo esquerdo de um gato jovem com insuficiência cardíaca congestiva e morte.

Congestive heart failure in a young cat with excessive moderator bands (false tendons) in the left ventricle / Insuficiência cardíaca congestiva em um gato jovem com bandas moderadoras excessivas (falsos tendões) em ventrículo esquerdo

Left ventricular false tendons are fibrous or fibromuscular bands that transverse the ventricular cavity and have no attachment to the mitral valve in many species. In cats it is considered a congenital defect that is rarely related to clinical disease and death in adult cats. A 45 days-old mixed breed cat had a history of inappetence since birth. At the physical exam the patient was lethargic and presented restrictive dyspnoea. At necropsy, there were marked ascites, hydrothorax, hepatomegaly with enhanced lobular pattern (nutmeg liver), and the lungs were markedly diminished (compressive pulmonary atelectasis). The heart was enlarged due to marked dilation of the cardiac chambers. Moreover, multiple slightly whitish and irregular cord-like structures were connecting the posterior papillary muscle to the interventricular septum (excessive moderator bands /left ventricular false tendons) at the left ventricle. Microscopically, these structures were characterized by a marked proliferation of fibrous connective tissue intermixed with Purkinje cells and well-differentiated cardiomyocytes lined by a single layer of endocardium. This study described a case of excessive moderator bands (left ventricular false tendons) in a young cat associated with congestive heart failure and death.(AU)

Falsos tendões são bandas fibrosas ou fibromusculares que atravessam a cavidade do ventrículo esquerdo, sem ligação com a valva mitral, em várias espécies. Nos gatos, a alteração é considerada um defeito congênito que raramente está relacionada com alterações clínicas e morte em gatos adultos. Um gato de 45 dias de idade, sem raça definida e com histórico de inapetência desde o nascimento foi encaminhado para atendimento veterinário. Ao exame físico apresentou letargia e dispneia restritiva. À necropsia, havia acentuada ascite, hidrotórax, hepatomegalia com evidenciação do padrão lobular (fígado noz-moscada) e os pulmões apresentavam-se acentuadamente diminuídos (atelectasia pulmonar compressiva). O coração apresentava acentuada dilatação das câmaras cardíacas. Em ventrículo esquerdo, havia numerosas estruturas brancacentas semelhantes a cordas conectando o músculo papilar ao septo interventricular (bandas moderadoras excessivas/falsos tendões). Microscopicamente, estas estruturas apresentavam acentuada proliferação de tecido conjuntivo fibroso, além de células de Purkinje e cardiomiócitos bem diferenciadas revestidas por uma única camada de endocárdio. O objetivo deste trabalho é descrever um caso de bandas moderadoras excessivas (falsos tendões) em ventrículo esquerdo de um gato jovem com insuficiência cardíaca congestiva e morte.(AU)

Pimobendan em gatos / Pimobendan in cats

As miocardiopatias são as cardiopatias mais comumente diagnosticadas em felinos domésticos. A cardiomiopatia hipertrófica (CMH) soma a maioria dos casos de cardiomiopatias em pacientes atendidos na rotina da medicina interna de felinos. Gatos com doenças cardíacas podem não apresentar manifestações clínicas evidentes podendo apresentar sinais sutis de insuficiência cardíaca (IC) ao longo do tempo de modo que em um dado momento descompensam e evidenciam sinais clínicos. O pimobendan é um fármaco denominado inodilatador devido a sua capacidade de promover inotropismo positivo e vasodilatação. Apesar de escassos, os estudos existentes com a utilização de pimobendan demonstram boa tolerância em gatos saudáveis e com cardiopatias diversas. Atualmente, o uso do pimobendan em gatos é extra bula e a dose baseia-se em estudos realizados com cães. No entanto, sabe-se que as concentrações plasmáticas diferem entre as espécies o que pode requerer possíveis ajustes. A terapia da IC em gatos é bastante discutida e evidências recentes demonstram que o pimobendan pode ser um aliado no tratamento de diversas doenças cardíacas que levem à disfunção sistólica sendo capaz de prover melhora dos sinais clínicos e até aumento da expectativa de vida desses pacientes. Contudo, pesquisas são necessárias para melhor entendimento dos efeitos hemodinâmicos do medicamento em gatos com disfunção diastólica.

Myocardiopathies are the most diagnosed heart disease in domestic cats. Hypertrophic cardiomyopathy (HCM) adds up to most cases of cardiomyopathies in patients seen in the routine of feline internal medicine. Cats with heart disease may not have evident clinical manifestations and may show subtle signs of heart failure (HF) over time so that at a given moment they decompensate and show clinical symptoms. Pimobendan is an inodilator drug due to its ability to promote positive inotropism and vasodilation. Although scarce, the existing studies with the use of pimobendan demonstrate good tolerance in healthy cats with various heart diseases. Currently, the use of pimobendan in cats is off-label and the dose is based on studies conducted in dogs. However, it is known that plasma concentrations differ between species, which may require possible adjustments. The therapy of HF in cats is widely discussed and recent evidence shows that pimobendan can be an ally in the treatment of various heart diseases that lead to systolic dysfunction, being able to provide improvement in clinical signs and even increase the life expectancy of these patients. However, research is necessary to better understand the hemodynamic effects of the drug in cats with diastolic dysfunction.

Clinical approach for treating dilated cardiomyopathy in a hog-nosed skunk (Conepatus chinga)

Background: Dilated cardiomyopathy (DCM) is a multifactorial disease characterized by systolic dysfunction of myocardium, affecting domestic animals like dogs, cats, and ferrets. It was sporadically described in non-domestic species, generally as a necropsy observation. The hog-nosed skunk (Conepatus chinga) is a small mammal, carnivore, belonging to the Mephitidae family, found in southern South America, and considered as concerned in a conservation status of the species. The goal of this issue is report the first clinical approach of dilated cardiomyopathy in a young hog-nosed skunk, elucidating the challenging aspects of the diagnostic, therapy, and clinical outcome. Case: A newborn hog-nosed skunk (Conepatus chinga) was found in a farm of southern Brazil in poor nutritional and behavioral conditions. Thirty days of nutritional supplementation based on cow's milk, fruits and insects were necessary to recover its body weight score and activity level. However, 2 months after adoption, the skunk showed acute dyspnea and abnormal breath sound, decreased appetite, and loss of weight. Firstly, these signs were associated with a possible pulmonary infection or other respiratory disease. However, the general cardiomegaly and pulmonary edema pattern observed on the thoracic radiography, changed the clinical approach, conducting the presumptive diagnosis to congestive heart failure (pulmonary edema) caused by an unknown cardiac disease as a dilated cardiomyopathy (CDM). An adequate physical, echocardiographic, electrocardiographic, and hematological evaluation was possible only after chemical restraint by sevofluorane. Systolic heart murmur and pulmonary cracking sounds were detected on thoracic auscultation. These findings associated to the echocardiography features of four chamber dilatation, systolic (fractional shortening-FS = 9% and ejection fraction-EF= 22%) and diastolic (mitral E/A ratio = 4.93) dysfunctions, and bilateral ventriculoatrial regurgitation (mitral and tricuspid) were highly correlated with DCM. Considering the etiologies of CDM described in domestic species and the poor nutritional condition previously observed in the case, nutritional and idiopathic etiologies of DCM were considered for this case. Therapy was based on furosemide at hospital (4 mg/kg subcutaneous, single doses) and home (2 mg/kg orally, BID), enalapril maleate (0.5 mg/kg orally, every 48 h), taurine supplementation (100 mg orally, SID), and pimobendan (0.5 mg/kg orally, BID). Clinical improvement was already observed on the second day of treatment, and monitored for 5 months, when the skunk was completely revaluated. The second echocardiographic exam showed improvement in systolic (FS = 20% and EF = 43%) and diastolic functions (mitral E/A ratio = 2.05), tricuspid regurgitation was not observed, and decrease the left atrial and ventricular dimensions were seen. Due to good clinical outcome, furosemide was gradually reduced until complete withdrawal without any clinical complications or worsening. After 30 months of therapy of pimobendan, taurine, and enalapril maleate, the skunk has good quality captive life without congestive heart failure recurrence. Discussion: The lack of information about DCM in hog-nosed skunk turns the clinical diagnosis and therapy challenging. However, the radiographic and echocardiographic features seamed to lead the same domestic animal patterns. The therapy based on decrease the cardiac overload, increase the myocardial inotropic function (pimobendan and taurine) resulted on excellent clinical and echocardiographic outcome. Although the etiologies of DCM in this species are not stablished, the diagnostic and therapeutic approaches applied resulted on excellent clinical results, and therefore may provide useful information about this cardiac condition in skunk species.

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)