Avaliação Ecocardiográfica da Função Cardíaca Materna em Cadelas da Raça São Bernardo
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2009
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As alterações ecocardiográficas durante a gestação normal estão bem documentadas na mulher. Em contraste, escassa informação está disponível acerca da função cardíaca em cadelas gestantes. No presente estudo, foi realizada a avaliação ecocardiográfica (2D, ModoM, Doppler e TDI) de 7 cadelas gestante saudáveis de raça São Bernardo, tendo sido realizados 3 exames durante a gestação (21º28º, 40º e 60º dias) e um 48 semanas pósparto. O exame foi realizado segundo a abordagem paraesternal direita e esquerda, utilizando um ecógrafo equipado com uma sonda sectorial de frequência variável (3.57.5 MHz), e foi obtido em simultâneo um ECG durante todas as medições. Três a cinco ciclos representativos foram medidos para cada animal, a partir dos quais se calculou a média.
A frequência cardíaca registou um aumento máximo ao 60º dia e o débito cardíaco também aumentou significativamente na fase final da gestação. Foi observada hipertensão sistémica ao longo de toda a gestação, com o valor máximo na sua fase inicial (21º28º dia). Em comparação com os valores do pósparto, ao 40º dia houve um aumento do diâmetro do ventrículo esquerdo em sístole (8%) e uma diminuição da fracção de encurtamento (14%) e fracção de ejecção (6%). Ambas as velocidades transmitrais E e A diminuíram ao 21º28º dia de gestação (14% e 17% respectivamente) e aumentaram até ao fim da gestação para valores semelhantes ao pósparto. Não foram observadas diferenças entre o rácio E/A durante a gestação e pósparto. A função sistólica avaliada pela velocidade TDI S’ permaneceu inalterada na margem septal e aumentou na margem lateral (60º dia), quando comparada com os valores do pósparto. A função diastólica avaliada pela velocidade TDI A’ aumentou durante a gestação na margem septal e lateral do anel mitral, resultando numa diminuição do rácio E’/A’, especialmente ao 60º dia.
A gestação, um estado natural crónico de sobrecarga de volume, tem importantes efeitos em variáveis hemodinâmicas e ecocardiográficas. No presente estudo demonstrámos um aumento de pressão arterial, uma diminuição da função sistólica do ventrículo esquerdo a meio da gestação, um aumento de débito cardíaco na fase final da gestação e um declínio ao longo da gestação da função diastólica, demonstrado pela velocidade TDI ’. Este estudo providencia intervalos de normalidade para vários índices ecocardiográficos em cadelas gestantes São Bernardo, embora mereça ulterior investigação com uma amostra mais alargada e heterogénea.
Echocardiographic changes during normal pregnancy are well documented in women. In contrast, sparse information is available regarding cardiac function during pregnancy in dogs. In the present study, an echocardiographic examination (2D, Mmode, Doppler and TDI) was carried out in 7 healthy pregnant female Saint Bernard dog, three times during their pregnancy (2128th, 40th and 60th days) and one time 48 weeks postpartum. The exam was performed from right and left parasternal location, using an ultrasound unit equipped with a variablefrequency (3.57.5 MHz) phasedarray transducer, and a simultaneous 1lead ECG was obtained during all measurements. Three to five representative cycles were measured and averaged for each animal. Heart rate increased maximally at day 60th, and cardiac output also increased significantly at latepregnancy. Hypertension was observed throughout pregnancy, reaching a maximum in earlypregnancy (day 2128th). Compared with postpartum values, at day 40th there was an increase in left ventricle (LV) endsystolic diameter (8%), and a decrease of fractional shortening (14%) and ejection fraction (6%). Both transmitral E and A velocities decreased at day 2128th of pregnancy (14% and 17%, respectively) and increased until the end of pregnancy to values similar to postpartum. No differences were observed between E/A ratio during pregnancy and postpartum. Systolic function assessed by TDI S’ velocity was unaltered at the septal margin and increased at the lateral margin (day 60th), as compared with postpartum evaluation. Diastolic function assessed by TDI A’ velocity increased during pregnancy at the septal and lateral margins of mitral annulus, resulting in a decrease of E’/A’, especially at day 60th. Pregnancy, a chronic, natural volumeoverload state, has important effects on hemodynamic and echocardiographic variables. In the present work we demonstrated an increase of blood pressure, a decrease of LV systolic function during midpregnancy, an increase of cardiac output during latepregnancy, and a decline throughout pregnancy of diastolic function, as demonstrated by TDI A’ velocity. This study gives normal ranges for several echocardiographic indices in pregnant Saint Bernard dogs, although it deserves further investigation with a larger and heterogeneous sample.
Echocardiographic changes during normal pregnancy are well documented in women. In contrast, sparse information is available regarding cardiac function during pregnancy in dogs. In the present study, an echocardiographic examination (2D, Mmode, Doppler and TDI) was carried out in 7 healthy pregnant female Saint Bernard dog, three times during their pregnancy (2128th, 40th and 60th days) and one time 48 weeks postpartum. The exam was performed from right and left parasternal location, using an ultrasound unit equipped with a variablefrequency (3.57.5 MHz) phasedarray transducer, and a simultaneous 1lead ECG was obtained during all measurements. Three to five representative cycles were measured and averaged for each animal. Heart rate increased maximally at day 60th, and cardiac output also increased significantly at latepregnancy. Hypertension was observed throughout pregnancy, reaching a maximum in earlypregnancy (day 2128th). Compared with postpartum values, at day 40th there was an increase in left ventricle (LV) endsystolic diameter (8%), and a decrease of fractional shortening (14%) and ejection fraction (6%). Both transmitral E and A velocities decreased at day 2128th of pregnancy (14% and 17%, respectively) and increased until the end of pregnancy to values similar to postpartum. No differences were observed between E/A ratio during pregnancy and postpartum. Systolic function assessed by TDI S’ velocity was unaltered at the septal margin and increased at the lateral margin (day 60th), as compared with postpartum evaluation. Diastolic function assessed by TDI A’ velocity increased during pregnancy at the septal and lateral margins of mitral annulus, resulting in a decrease of E’/A’, especially at day 60th. Pregnancy, a chronic, natural volumeoverload state, has important effects on hemodynamic and echocardiographic variables. In the present work we demonstrated an increase of blood pressure, a decrease of LV systolic function during midpregnancy, an increase of cardiac output during latepregnancy, and a decline throughout pregnancy of diastolic function, as demonstrated by TDI A’ velocity. This study gives normal ranges for several echocardiographic indices in pregnant Saint Bernard dogs, although it deserves further investigation with a larger and heterogeneous sample.
Descrição
Dissertação de Mestrado em Medicina Veterinária
Palavras-chave
Cadela , Período de gestação , Frequência cardíaca , Ecocardiografía