Brachycephalic syndrome (BS) in dogs is characterized by the combination of primary and secondary upper respiratory tract abnormalities and may result in significant upper airway obstruction. It can trigger inspiratory dyspnea, culminating in secondary respiratory distress, soft tissue edema, upper airway obstruction, turbulent airflow, inspiratory noise, and even death. These changes lead to increased resistance of the air passages, which can cause elevation of pulmonary pressure and clinical manifestations attributable to pulmonary hypertension. The consequence is right-sided cardiac remodeling (Cor pulmonale) with possible progression to right congestive heart failure. To investigate the effects of BS on the cardiovascular system, 28 animals were recruited for a prospective study and assigned to either the Brachycephalic Group (BG), composed of 22 French bulldogs with BS or the Control Group (CG), which was composed of 6 healthy Beagle dogs. All animals underwent a detailed physical examination, as well as laboratory analyses, electrocardiography, echocardiography, chest radiography and indirect measurement of systemic arterial blood pressure. The most relevant finding was a lower PaO2 (90.6±12.9mmHg) in BG as compared to CG (104.9±5.2), (p≤0.05), possibly attributable to hypoventilation due to anatomical alterations.

We report the first documented case of endocarditis associated with Bartonella clarridgeiae in a dog in Latin America. Infective vegetative valvular aortic endocarditis was diagnosed in a 10-year-old male mixed breed dog. The dog presented grade V/VI systolic and diastolic murmur, hyperthermia, and progressive weight loss. Cardiomegaly and presence of diffuse alveolar pattern in the lung fields were observed in the thorax radiography evaluation. Irregular and hyperechogenic structures adhered to the aortic leaflets, causing obstruction of the left ventricular outflow tract and severe aortic insufficiency, were observed in the echocardiography evaluation. A vegetative, whitish, hardened structure measuring 1.0 cm in diameter was observed in aortic semilunar valve at necropsy. Based on a combination of pre-enrichment insect-based medium liquid culture, quantitative real-time and conventional PCR assays based on nuoG and gltA genes, respectively, followed by sequencing and phylogenetic inferences, B. clarridgeiae DNA was detected in the patient’s aortic valve lesions. Clinical, echocardiographic, anatomopathologic and molecular features supported the diagnosis of severe aortic vegetative endocarditis possibly caused by B. clarridgeiae in a dog in Brazil.

This research focuses on the adjustments in systolic and diastolic functions that are not fully understood in dogs submitted to athletic training. Beagle dogs carried out an endurance training program (ETP) prescribed from the external training load, corresponding to 70–80% of the lactate threshold (VLT) velocity. Eighteen dogs were randomly assigned to two groups: control (C, n = 8), active dogs that did not perform any forced exercise, and trained (T, n = 10), submitted to the ETP during eight weeks. All dogs were evaluated before and after the ETP period using two-dimensional echocardiography, M-mode, Doppler, and two-dimensional speckle tracking. A principal component analysis (PCA) of the echocardiographic variables was performed. The ETP improved the left ventricular internal dimension at the end of diastole (LVDd), the left ventricular internal dimension at the end of diastole to aorta ratio (LVDd: Ao), and the strain rate indices. PCA was able to capture the dimensionality and qualitative echocardiography changes produced by the ETP. These findings indicated that the training prescribed based on the lactate threshold improved the diastolic and systolic functions. This response may be applied to improve myocardial function, promote health, and mitigate any injuries produced during heart failure.

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Mitral valve disease (MVD) is a progressive disease that can reduce cardiac output. Activation of the sympathetic autonomic nervous system is one of the body's first responses in order to maintain cardiac output, but may have deleterious effects on the cardiovascular system. This study investigated the effect of metoprolol on heart rate variability and quality of life in dogs with severe MVD (stage C, according to the guidelines of the American College of Veterinary Internal Medicine). Eight dogs between nine and thirteen years of age were enrolled and screening tests such as complete blood count, serum biochemistry profile, systolic blood pressure, thoracic radiographs, electrocardiogram, echocardiogram and long-term electrocardiography (24 hours) were performed. The patients were treated with enalapril, furosemide, spironolactone, and pimobendan until considered clinically stable, and metoprolol was then added to the therapy. One month later, all animals were re-assessed. Owners responded to a questionnaire about their dog's quality of life before and after beta-blocker therapy. The value for pNN50 (percentage difference between adjacent N-N intervals more than 50 ms) was significantly higher (P=0.039) after treatment with metoprolol, indicating higher heart rate variability as indicated by the increased parasympathetic component. Furthermore, quality of life was improved in 30% of patients after metoprolol was initiated. The results suggest that treatment with beta-blockers in dogs with stage C MVD may yield additional benefits in comparison to standard CHF treatment.