ABSTRACT
The aim of this study was to develop an experimentally-induced canine model of left ventricular hypertrophy through banding of the ascending aorta using nylon ties. Seven clinically normal dogs free of cardiovascular disease were used. Nylon tie was used in banding the mid-ascending aorta. Clinical, radiographic and echocardiographic evaluations were done at 1.5, 3 and 6 months. Dogs were euthanized at 6 months for post mortem and histopathological evaluation. Clinically, dogs did not exhibit any signs of cardiovascular disease at 1.5 or 3 months, while at 6 months two dogs (28.6 %) exhibited mild weight loss, exercise intolerance and heart murmurs. Radiographic evaluation revealed significant increase in cardiac size only at 6 months based on measurement of the cardiothoracic area evaluation. Echocardiography revealed increased left ventricular wall thickness starting from 1.5 month, although this increase was statistically significant at 3 and 6 months (p > 0.05). Left ventricular hypertrophy was confirmed by post mortem examination. Histopathological sections of left ventricle in all dogs demonstrated myocyte hypertrophy and interstitial fibrosis. This model simulates the naturally occurring ventricular hypertrophy using a rapid and economic technique. Such models are required to understand pathogenesis of heart disease and to develop effective treatment strategy.
Subject(s)
Animals , Dogs , Aortic Valve Stenosis , Hypertrophy, Left Ventricular/veterinary , Nylons , PressureABSTRACT
A cardiomiopatia hipertrófica (CMH) é a principal cardiopatia dos felinos e é caracterizada por hipertrofia miocárdica concêntrica, sem dilatação ventricular. O ecocardiograma é o melhor meio diagnóstico não invasivo para a diferenciação das cardiomiopatias e é considerado padrão ouro para a detecção de hipertrofia ventricular presente na CMH. Alterações eletrocardiográficas também são comuns em animais com CMH e o eletrocardiograma (ECG) é um teste de triagem para detecção de hipertrofia ventricular em humanos, sendo um exame rápido e facilmente disponível. Em gatos, poucos estudos foram realizados quanto à sensibilidade e especificidade do ECG na detecção de hipertrofia ventricular. Com a intenção de avaliar o uso do ECG como ferramenta de triagem para diagnóstico de CMH em felinos, gatos da raça Persa (n=82) foram avaliados por meio de exames ecocardiográfico e eletrocardiográfico. Animais com bloqueios e/ou distúrbios de condução foram excluídos da análise estatística (n=22). Posteriormente, os animais incluídos foram classificados em: normais (n=38), suspeitos (n=6) e acometidos pela CMH (n=16)...
Hypertrophic cardiomyopathy (HCM) is the most common feline heart disease and is characterized by increased cardiac mass with a hypertrophied and not dilated left ventricle. The echocardiography is the best noninvasive diagnostic tool for the differentiation of cardiomyopathies and is considered the gold standard for detection of ventricular hypertrophy present in HCM. Electrocardiographic changes are also common in animals with HCM and the electrocardiogram (ECG) is quick, easy and highly available screening test for the detection of ventricular hypertrophy in humans. In cats, few studies have been conducted regarding the sensitivity and specificity of ECG in detecting ventricular hypertrophy. With the intention of evaluating the use of ECG as a screening tool for diagnosis of HCM in cats, Persian cats (n=82) were evaluated by echocardiographic and electrocardiographic examinations. Animals with blocks and/or conduction disturbances were excluded from statistical analysis (n=22). Subsequently the animals included were classified as normal (n=38), suspicious (n=6) and affected by HCM (n=16)...