Antioxidative enzyme activity and total antioxidant capacity in serum of dogs with degenerative mitral valve disease.

This study was designed to evaluate the antioxidative status of serum by measuring its total antioxidant capacity, as well as the antioxidant enzyme activity (superoxide dismutase, catalase, and glutathione reductase), in dogs with various stages of degenerative mitral valve disease (DMVD) compared to healthy controls. In total, 71 client-owned dogs in different stages of DMVD, which included healthy controls, took part in the study. Following an anamnesis, clinical examination, standard transthoracic echocardiograpic examination, chest X-ray, complete blood (cell) count, and serum biochemistry, dogs were divided into 2 study groups. Blood was drawn from each dog once at the time of presentation and selected antioxidant parameters were measured using commercially available assay kits. The activity of superoxide dismutase gradually decreased in the more advanced stages of DMVD, while the activity of catalase was significantly higher in the group of dogs with asymptomatic DMVD compared to healthy controls and dogs with symptomatic DMVD. No significant changes were noted in total antioxidant capacity and the activity of glutathione reductase. Results suggested that DMVD has a significant impact on the activity of superoxide dismutase and catalase in the serum of the tested dogs. Knowledge of changes in the activity of antioxidative enzymes may warrant further studies, possibly to evaluate the potential role of compounds with antioxidative properties in the clinical outcome of dogs with DMVD.

La présente étude a été conçue afin d'évaluer le statut antioxydant du sérum en mesurant sa capacité antioxydante totale, ainsi que l'activité antioxydante enzymatique (superoxyde dismutase, catalase, et glutathion réductase), chez des chiens avec des degrés divers de maladie dégénérative de la valvule mitrale (DMVD) comparativement à des témoins en santé. Au total, 71 chiens appartenant à des clients à différents stades de DMVD, qui incluaient des témoins en santé, ont pris part à cette étude. À la suite de la prise d'anamnèse, d'un examen clinique, d'un examen échocardiographie transthoracique standard, de radiographie thoracique, d'un comptage cellulaire sanguin complet, et d'analyse biochimique sérique, les chiens étaient séparés en deux groupes d'étude. Du sang fut prélevé de chaque chien une fois au moment de la présentation et les paramètres antioxydants sélectionnés furent mesurés à l'aide d'une trousse disponible commercialement. L'activité de la superoxyde dismutase diminuait graduellement dans les stades plus avancés de DMVD, alors que l'activité de la catalase était significativement plus élevée dans le groupe de chiens avec une DMVD asymptomatique comparativement aux témoins en santé et aux chiens avec une DMVD symptomatique. Aucun changement significatif n'était noté dans la capacité antioxydante totale et dans l'activité de la glutathion réductase. Les résultats suggèrent que la DMVD a un impact significatif sur l'activité de la superoxyde dismutase, et de la catalase dans le sérum des chiens testés. Des connaissances sur les changements dans l'activité des enzymes antioxydantes pourraient justifier des études additionnelles, possiblement pour évaluer le rôle potentiel de produits avec des propriétés antioxydantes dans le devenir clinique de chiens avec DMVD.(Traduit par Docteur Serge Messier).

Analysis of Haematological and Biochemical Blood Parameters After Electrical Cardioversion of Atrial Fibrillation in Dogs.

INTRODUCTION: Electrical cardioversion is a therapeutic procedure used to convert various types of arrhythmias back to sinus rhythm. It is used to restore the sinus rhythm in dogs with atrial fibrillation. The effect of the electrical energy used during cardioversion on red blood cells (RBC) is not fully understood. Studies on humans reported lysis of RBC following electrical cardioversion. Similar studies have not been carried out on dogs. The aim of the study was to assess the effect of electrical cardioversion on chosen RBC parameters. MATERIAL AND METHODS: The study was carried out on 14 large and giant breed dogs weighing from 30 to 84 kg with lone atrial fibrillation (lone AF). Electrical cardioversion was carried out under general anaesthesia by biphasic shock with 70-360 J of energy. Blood was collected at T0 - during atrial fibrillation, prior to cardioversion, and at T1 - 30 min after electrical cardioversion. Complete blood counts as well as total and direct bilirubin concentrations were evaluated. A maximum output of 360 J was used. RESULTS: In all cases, electrical cardioversion was effective, and no significant changes in the number of RBC and RBC indices were noted. Similarly, there were no statistically significant differences in the levels of total and direct bilirubin. CONCLUSION: Electrical cardioversion in dogs led neither to statistically nor clinically significant RBC lysis.

Intracardiac electrophysiological conduction parameters in adult dogs.

BACKGROUND: Invasive electrophysiology study (EPS) is one of the most important adjunct tests for the evaluation of arrhythmias in human medicine. However, EPS is neither well known nor widely used in veterinary medicine. OBJECTIVE: To define the values for intracardiac conduction parameters determined during invasive EPS in dogs. ANIMALS AND METHODS: The study included 16 admitted dogs of various breeds, sex and ages and 6 control Beagles. In the Beagles, EPS was performed twice at 6-month intervals in order to verify the reproducibility of the results. RESULTS: No significant differences were found between the results of the baseline and repeated EPS performed in the Beagles. We found retrograde conduction in 13 (59%) out of 22 dogs and including 4 (31%) animals with concomitant 'jumps' in the atrioventricular node conduction curve, pointing to the presence of dual conduction in this node. The mean values of the AV and retrograde VA Wenckebach points equaled to 220 and 360 ms, respectively, suggesting that the capability of the descending route is higher than that of the ascending route. CONCLUSION: The values determined in this study may be helpful in early detection of abnormalities in the electrical conduction system of the heart.

Prevalence of Arrhythmias in Dogs Examined between 2008 and 2014.

INTRODUCTION: The prevalence of arrhythmias in dogs and the influence of sex, breed, age, and body weight were analysed over a seven-year span. MATERIAL AND METHODS: In total, 1189 referrals for cardiological examination by electrocardiography were received at one academic centre in Poland between 2008 and 2014. The largest proportion of the examined dogs were cross-breeds with body weight below 25 kg (n = 153, 12.87%), followed by German Shepherds (n = 122, 10.26%), Labrador Retrievers (n = 68, 5.72%), Yorkshire Terriers (n = 63, 5.3%), and Boxers (n = 60, 5.05%). Retrospective analysis was made of 1201 standing or right recumbent electrocardiograms without pharmacological sedation. The prevalence of arrhythmias was examined in terms of sex, age, body weight, and breed of the dogs. RESULTS: A total of 630 (52.46%) electrocardiograms showed no signs of arrhythmia, but 96 (7.99%) and 475 (39.55%) pointed to physiological and pathological arrhythmias respectively. The most commonly diagnosed type was atrial fibrillation with 33.68% incidence, followed by ventricular arrhythmias (28%), sinus pauses (27.58%), supraventricular arrhythmias (24%), and atrioventricular blocks (22.95%). Pathological arrhythmias were most commonly found in male dogs and in German Shepherds. CONCLUSIONS: Atrial fibrillation predominated, followed by premature ventricular complexes. Male dogs were generally more prone to heart rhythm disturbances.

Normal Values for Heart Electrophysiology Parameters of Healthy Swine Determined on Electrophysiology Study.

BACKGROUND: Swine are a well-recognized animal model for human cardiovascular diseases. Despite the widespread use of porcine model in experimental electrophysiology, still no reference values for intracardiac electrical activity and conduction parameters determined during an invasive electrophysiology study (EPS) have been developed in this species thus far. OBJECTIVES: The aim of the study was to develop a set of normal values for intracardiac electrical activity and conduction parameters determined during an invasive EPS of swine. MATERIAL AND METHODS: The study included 36 healthy domestic swine (24-40 kg body weight). EPS was performed under a general anesthesia with midazolam, propofol and isoflurane. The reference values for intracardiac electrical activity and conduction parameters were calculated as arithmetic means ± 2 standard deviations. RESULTS: The reference values were determined for AH, HV and PA intervals, interatrial conduction time at its own and imposed rhythm, sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), anterograde and retrograde Wenckebach points, atrial, atrioventricular node and ventricular refractory periods. No significant correlations were found between body weight and heart rate of the examined pigs and their electrophysiological parameters. CONCLUSIONS: The hereby presented reference values can be helpful in comparing the results of various studies, as well as in more accurately estimating the values of electrophysiological parameters that can be expected in a given experiment.

Atrioventricular valvular anomalies and their role in the etiopathogenesis of cardiorespiratory syndrome in farmed common foxes (Vulpes vulpes).

BACKGROUND: Cardiorespiratory syndrome of common foxes is associated with a mortality rate ranging from 2.1% to 20%. OBJECTIVE: The aim of this study was to analyze the prevalence of cardiac abnormalities in common foxes (Vulpes vulpes) from Polish farms with a history of cardiorespiratory syndrome. ANIMALS AND METHODS: The prevalence of cardiac abnormalities in common foxes from a Polish farm with a history of cardiorespiratory syndrome was assessed as well as morphological examination of 60 heart specimens from clinically healthy animals. In addition, 38 foxes were examined echocardiographically and subjected to postmortem examination. RESULTS: Atrioventricular valvular abnormalities were found in 57 out of the 98 (58%) analyzed hearts. The abnormalities of the mitral valve documented in more than 20% of the foxes in involved tendinous chords (completely lacking or shortened), papillary muscles and mitral cusps associated with both insufficiency and stenosis of the left atrioventricular orifice. Abnormalities of the tricuspid valve included significant shortening of the tendinous chords and thickening of the valve cusps with the impairment of their mobility. The results of the echocardiographic and postmortem examination were consistent in 79% of the cases. The specimens collected from animals with and without atrioventricular valvular anomalies did not differ significantly in terms of cardiomyocyte width, number of inflammatory cells, adipose tissue content and presence of polychromatic cardiomyocytes. CONCLUSION: Congenital atrioventricular valvular defects may be involved in the etiology of cardiorespiratory syndrome in common foxes, and echocardiography can be used as a measure of stock's health and a criterion for selection for mating.

Myocarditis in dogs: etiology, clinical and histopathological features (11 cases: 2007-2013).

BACKGROUND: Myocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination. RESULTS: The examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one. CONCLUSIONS: Although the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.