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Hypercortisolism is one of the most common endocrine diseases in dogs. In humans, it is clearly associated with a higher risk of cardiovascular events, but studies in dogs are scarce. To investigate the arrhythmogenic risk of dogs with naturally-occurring hypercortisolism (NOHC), indices of variability and instability of the QT interval were retrospectively studied in 38 dogs with NOHC and prospectively studied in 12 healthy dogs: variance (QTv), total instability (TI), short-term (STI) and long-term (LTI), and mean (QTm). Except for QTm, all parameters studied were higher in the NOHC group than in the control group. In addition, STI and QTv showed moderate positive correlation with left ventricle wall thickness. The NOHC group was subdivided according to cortisol suppression pattern in the low-dose dexamethasone suppression test. All electrocardiographic indices of partial and absent suppression patterns were numerically higher than healthy dogs. QTv and TI were lower in the control group than in both NOHC subgroups. LTI and STI were lower in the CG than in the group with the partial suppression pattern. There was no statistical difference between sex groups in any of the electrocardiographic parameters studied. This result might indicate that the etiology of NOHC, and its consequent influence on hypothalamus-pituitary-adrenal axis could interfere on the heterogeneity of ventricular repolarization parameters in different ways, especially in the short-term and the long-term stability; however further studies are necessary to understand the role of cortisol on electrical instability in dogs.

ResumoO presente trabalho tem como objetivo realizar uma análise dos métodos indiretos da avaliação da pressão da artéria pulmonar com base na literatura científica. Por meio de levantamento bibliográfico, artigos científicos foram selecionados conforme a sua relevância para o tema. A avaliação da pressão da artéria pulmonar permite inferir se o paciente apresenta hipertensão arterial pulmonar (HAP), a qual está associada a um prognóstico ruim em cães. O exame padrão é a cateterização da artéria pulmonar, porém este método não tem Development, v. 9, n. 3, e44932309, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i3.2309 2 sido utilizado na rotina da medicina veterinária porque o quadro clínico do animal comumente não permite a sedação e por se tratar de um procedimento oneroso. O diagnóstico da HAP em pequenos animais por meio da ecodopplercardiografia pode ser obtido com a avaliação da regurgitação da valva tricúspide ou pulmonar, características subjetivas e mensuração do tempo de aceleração (TA) e relação entre o tempo de aceleração e o tempo de ejeção do fluxo pulmonar (TA:TE), relação entre a artéria pulmonar e a veia pulmonar, distensibilidade da artéria pulmonar direita (RPAD), e ainda por avaliação da função do ventrículo direito, principalmente o índice de TEI e o strain. O objetivo desta revisão foi demonstrar as principais técnicas ecocardiográficas para estimar HAP, com o intuito de contribuir com o cardiologista no diagnóstico da HAP. Todas as técnicas apresentam fatores positivos e negativos, porém é importante ressaltar que não existe uma técnica ideal, e a forma mais assertiva de se chegar ao diagnóstico é associando as diversas técnicas. Palavras-chave: Hipertensão Arterial Pulmonar; Índice de Distensibilidade da Artéria Pulmonar Direita; Regurgitação da Pulmonar; Regurgitação da Tricúspide. Abstract This paper aims to perform an analysis of the indirect methods of pulmonary artery pressure assessment based on the scientific literature. Through bibliographic survey, scientific articles were selected according to their relevance to the theme.The assessment of pulmonary artery pressure allows to infer whether the individual has pulmonary arterial hypertension (PAH), which is associated with a poor prognosis in dogs diagnosed with mitral valve degeneration. The standard examination is pulmonary artery catheterization, but this method has not been used in routine veterinary medicine because the clinical status of the animal usually does not allow sedation and it is a costly procedure. The diagnosis of PAH in small animals through Doppler echocardiography can be obtained by evaluating the regurgitation of the tricuspid or pulmonary valve, subjective characteristics and measurement of the acceleration time (AT) and the acceleration time-to-ejection time ratio of pulmonary artery (AT:ET), pulmonary artery-to-pulmonary vein ratio, distensibility of the right pulmonary artery (RAPD), and assessment of right ventricular function, especially TEI index and strain. The aim of this...

Hyperadrenocorticism is one of the most common endocrine diseases in dogs. In humans, it is clearly associated with a higher risk of cardiovascular events, but studies in dogs are scarce. To investigate the arrhythmogenic risk of dogs with hyperadrenocorticism, indices of variability and instability of the QT interval were studied in 38 dogs with hyperadrenocorticism and in 12 healthy dogs: variance (QTv), total instability (TI), short-term (STI) and long-term (LTI), and mean (QTm). Except for QTm, all parameters studied were higher in the hyperadrenocorticism group than in the control group. In addition, STI and QTv showed moderate positive correlation with left ventricle wall thickness. To a better understanding on the effect of the hypothalamus-pituitary-adrenal axis on ventricular repolarization, the hyperadrenocorticism group was subdivided according to the percentage of variation in plasma cortisol concentration (<30.1%; 30.1-60%; >60%) 8 hours after low-dose administration of dexamethasone. There was statistical difference in QTv, TI and LTI indices between the control group and the <30.1% and >60% groups, and in STI index between the control group and the >60% group. There was no statistical difference between sex groups in any of the electrocardiographic parameters studied. This result may indicate that the etiology of hyperadrenocorticism, and its consequent influence on hypothalamus-pituitary-adrenal axis could interfere on the heterogeneity of ventricular repolarization parameters in different ways, especially in the short-term stability; however further studies are necessary to understand the role of cortisol on electrical instability in dogs.