Morphogeometric Evaluation of the Left Ventricle and Left Atrioventricular Ring in Dogs: A Computerized Anatomical Study.

In veterinary, there is scarce availability of morphogeometric studies in normal and remodeled hearts; furthermore, ventricular geometry acts as an indicator of cardiac function. It is a highly necessary field of knowledge for the development of therapeutic protocols, especially surgical ones. The objectives of this study were: to obtain measurements of the left atrioventricular valve ring and left ventricle, to analyze the proportionality between the segments of the left cardiac chamber of normal hearts and to describe reference values for morphogeometric analysis of the left ventricle. For this, 50 hearts from small (Group 1-G1) and medium to large (Group 2-G2) dogs were laminated in the apical, basal and equatorial segments, and submitted to computer analysis to identify the perimeter of each segment and the left atrioventricular ring, wall thickness and distance from the atrioventricular sulcus to the apex. The largest internal perimeter was that of the equatorial. The basal segment had the highest mean for ventral parietal wall thickness, suggesting greater contractile reserve at that location. Considering the proportionality relationships, there was no statistical difference between the intersegmental perimeter indices for the two groups. This suggests that despite the animals' weight variations, the proportions between the left ventricular segments are maintained. Therefore, it is concluded that the data can be used as a standard of comparison for cardiac geometric assessments, as well as a basis for the development of therapeutic measures in the context of adverse cardiac remodeling.

Left ventricular chamber geometry in cardiomyopathies: insights from a computerized anatomical study.

AIMS: Some authors have hypothesized that left ventricular chamber dilatation in ischaemic and idiopathic cardiomyopathies results in spherical transformation. Aiming to characterize how this transformation occurs, a study was performed by comparing normal and dilated specimens regarding sphericity and proportionality in left heart chambers. It is important to provide data for the development of therapeutic strategies in these diseases. METHODS AND RESULTS: An anatomical study was performed by comparing normal (n = 10), ischaemic (n = 15), and idiopathic (n = 18) dilated human cardiomyopathic specimens regarding left ventricular chambers and their segmental proportionality to normal hearts. It was performed by capturing and processing images with proper software in three different levels of left ventricular chamber (basal, equatorial, and apical). These obtained data were analysed based on sphericity and proportionality by two dedicated indexes. Spherical shape: Calculated segmental indexes showed that dilated specimens were not spherical because they were smaller than as expected for a spherical shape (all values were <70% of a perfect sphere). Proportionality: There was no difference between basal index perimeters among groups, but apical index was lower in dilated specimens than in normal hearts, and so dilatation was not proportional to normal hearts. CONCLUSIONS: Left ventricular chambers of anatomical specimens with dilated cardiomyopathies did not display a spherical shape and were not proportional to normal hearts.

Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall.

INTRODUCTION: A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. OBJECTIVE: To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. METHODS: We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. RESULTS: Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). CONCLUSION: In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the basal, equatorial and apical regions of this chamber.

Updated canine infection rates for Dirofilaria immitis in areas of Brazil previously identified as having a high incidence of heartworm-infected dogs.

BACKGROUND: Canine heartworm infections were frequently diagnosed in Brazil before the new millennium. After the year 2000, the frequency of diagnosis showed a sharp decline; however, a few years later, new evidence indicated that the parasite was still present and that canine infection rates seemed to be increasing. Therefore, an updated survey of canine heartworm prevalence was conducted in several locations in south, southeast, and northeast Brazil. METHODS: Dogs from 15 locations having previously reported a high prevalence of heartworm infection were included in the survey according to defined criteria, including the absence of treatment with a macrocyclic lactone for at least 1 year. Blood samples from 1531 dogs were evaluated by an in-clinic immunochromatography test kit (Witness® Heartworm, Zoetis, USA) for detection of Dirofilaria immitis antigen. At each location, epidemiologic data, including physical characteristics and clinical signs reported by owners or observed by veterinarians, were recorded on prepared forms for tabulation of results by location, clinical signs, and physical characteristics. RESULTS: The overall prevalence of canine heartworm infection was 23.1%, with evidence of heartworm-infected dogs detected in all 15 locations studied. There was a tendency for higher prevalence rates in environmentally protected areas, despite some locations having less-than-ideal environmental temperatures for survival of vector mosquitoes. Among physical characteristics, it was noted that dogs with predominantly white hair coats and residing in areas with a high (≥20%) prevalence of heartworm were less likely to have heartworm infection detected by a commercial heartworm antigen test kit than were dogs with other coat colors. In general, dogs older than 2 years were more frequently positive for D. immitis antigen than were younger dogs. Clinical signs of heartworm infections were rare or owners were unable to detect them, and could not be used for reliable prediction of the presence of heartworm. CONCLUSIONS: These results indicate that the prevalence of D. immitis has increased in these areas of Brazil over the past few years. Small animal practitioners in these areas should include routine screening tests for heartworm infections in every dog's annual evaluation protocol and make sure to have uninfected dogs on prevention.

Idiopathic dilated cardiomyopathy: computerized anatomic study of relashionship between septal and free left ventricle wall / Cardiomiopatia dilatada idiopática: estudo anatômico computadorizado da relação entre o septo e a parede livre do ventrículo esquerdo

Introduction: A feature of dilated cardiomyopathy is the deformation of ventricular cavity, which contributes to systolic dysfunction. Few studies have evaluated this deformation bearing in mind ventricular regions and segments of the ventricle, which could reveal important details of the remodeling process, supporting a better understanding of its role in functional impairment and the development of new therapeutic strategies. Objective: To evaluate if, in basal, equatorial and apical regions, increased internal transverse perimeter of left ventricle in idiopathic dilated cardiomyopathy occurs proportionally between the septal and non-septal segment. Methods: We performed an anatomical study with 28 adult hearts from human cadavers. One group consisted of 18 hearts with idiopathic dilated cardiomyopathy and another group with 10 normal hearts. After lamination and left ventricle digital image capture, in three different regions (base, equator and apex), the transversal internal perimeter of left ventricle was divided into two segments: septal and not septal. These segments were measured by proper software. It was established an index of proportionality between these segments, called septal and non-septal segment index. Then we determined whether this index was the same in both groups. Results: Among patients with normal hearts and idiopathic dilated cardiomyopathy, the index of proportionality between the two segments (septal and non-septal) showed no significant difference in the three regions analyzed. The comparison results of the indices NSS/SS among normal and enlarged hearts were respectively: in base 1.99 versus 1.86 (P=0.46), in equator 2.22 versus 2.18 (P=0.79) and in apex 2.96 versus 3.56 (P=0.11). Conclusion: In the idiopathic dilated cardiomyopathy, the transversal dilatation of left ventricular internal perimeter occurs proportionally between the segments corresponding to the septum and free wall at the ...

Introdução: Uma das características da cardiomiopatia dilatada idiopática é a deformação da cavidade ventricular, a qual contribui para a disfunção sistólica. Poucos trabalhos julgam importante a avaliação dessa deformação ventricular levando em consideração regiões e segmentos do ventrículo, o que pode revelar detalhes importantes do processo de remodelamento, dando suporte a um melhor entendimento do seu papel no comprometimento funcional e ao surgimento de novas estratégias terapêuticas. Objetivo: Verificar se, em regiões diferentes, o aumento do perímetro transversal da câmara ventricular esquerda na cardiomiopatia dilatada idiopática ocorre de maneira proporcional entre o segmento septal e o não septal (parede livre). Métodos: Foi realizado um estudo anatômico com 28 corações adultos. Um grupo foi constituído por 18 corações com cardiomiopatia dilatada idiopática e outro grupo com 10 corações normais. Em três regiões diferentes (base, equador e ápice), o perímetro interno transversal do ventrículo esquerdo foi dividido em dois segmentos: septal e não septal. Foi criado um índice de proporcionalidade entre esses segmentos. Em seguida verificou-se se esse índice era o mesmo entre os grupos. Resultados: Entre corações normais e portadores de cardiomiopatia dilatada idiopática, o índice de proporcionalidade entre os dois segmentos (septal e não septal) não apresentou diferença significativa nas três regiões analisadas. Conclusão: Na cardiomiopatia dilatada idiopática, a dilatação transversal do septo é proporcional à dilatação da parede livre nas regiões basal, equatorial e apical da câmara ventricular esquerda. .

Avaliação morfogeométrica do ventrículo esquerdo e do anel valvar mitral na cardiomiopatia dilatada isquêmica ou idiopática: estudo comparativo computadorizado / Morphogeometric evaluation of left cardiac ventricle and mitral valval ring in dilated ischemic and idiopathic cardiomyopathies: computer assisted comparative study

INTRODUÇÃO: O conhecimento anatômico desempenha importante papel no desenvolvimento de técnicas diagnósticas e cirúrgicas. Com esse objetivo, na área cardiológica, se mostra fundamental para o entendimento do processo de remodelamento cardíaco que acompanha as cardiomiopatias dilatadas (CMD) tanto isquêmicas (CMDIsq) como idiopáticas (CMDId), de modo particular do ventrículo esquerdo (VE) e sua correlação com alterações do anel atrioventricular esquerdo, levando a graus variáveis de insuficiência cardíaca (IC). OBJETIVOS: Os objetivos desta pesquisa são: 1) Obter medidas do anel atrioventricular esquerdo (mitral) e do ventrículo esquerdo em corações normais, com CMDIsq ou CMDId, comparando-as entre si; 2) Analisar a proporcionalidade entre segmentos da câmara ventricular esquerda dos corações com CMDIsq ou CMDId em relação ao normal; 3) Determinar a esfericidade ou não da câmara ventricular esquerda nos corações com CMDIsq ou CMDId. MÉTODO: Foram analisados 43 corações humanos, divididos em três grupos: NORMAL (n=10), CMDIsq (n=15) e CMDId (n=18). De posse da medida da distância do sulco atrioventricular posterior até o ápice do VE, foram realizados cortes transversais baso-apicais seqüenciais e, após digitalização dos mesmos, por meio de método computadorizado, foram obtidas medidas perimetrais e espessura das paredes. Empregando-se o mesmo método, mensurou-se o perímetro do anel mitral. Foram criados índices de proporção porcentual entre os perímetros dos segmentos provenientes dos cortes do VE, comparando-os intergrupos. Nos dilatados os perímetros segmentares mensurados foram comparados com os perímetros esperados se considerássemos a câmara ventricular como uma esfera perfeita. Realizou-se a análise estatística dessas medidas e índices. RESULTADOS: O perímetro do anel mitral teve o seguinte resultado: somente o grupo CMDIsq teve média significativamente maior que o grupo NORMAL e houve baixo coeficiente de correlação com os perímetros ventriculares...

BACKGROUND: Anatomic knowledge is the cornerstone for the development of surgical and diagnostic image techniques and for understanding pathological entities. Understanding cardiac anatomy is essential for understanding cardiac remodeling in both ischemic and idiopathic dilated cardiomyopathies. Dysfunction in the physiological relationship between the morphology of left ventricle and its mitral ring plays an important role in the cardiac insufficiency etiopathogenesis. OBJECTIVES: 1) To compare morphology of left ventricle and its mitral ring among normal, ischemic and idiopathic dilated cardiomyophatic anatomic specimens; 2) To compare intra specimen ventricular segmental perimeters relationships between normal and dilated specimens; 3) To verify the presence of the spheroid shape of left ventricular chamber in dilated specimens. METHODS: It was analyzed 43 specimens of human hearts, classified in three groups: normal (n=10), dilated due to ischemic (n=15) or idiopathic cardiomyopathies (n=18). Several lengths were measured: the length from the posterior atrioventricular sulcus to the ventricular apex in the intact specimen; followed by three sequential transversal ventricular slicing in the basal, equatorial and apical level. Digital pictures were taken from these slices, in order to be analyzed in a computer assisted fashion. Internal perimeter and ventricular walls width of each slice were measured, as well the mitral ring perimeter. The three intra group perimeters were compared and correlated between themselves. Basal, equatorial and apical perimeter of each group was compared to their correspondent pairs inter groups. Regarding intra group relationships, for a given group, each slice perimeter was measured and considered as a percentage of the equatorial slice (index). This percentage was compared inter groups. Three perimeters were evaluated in both dilated groups, each one was compared to its expected value when considering left ventricular...