ABSTRACT
O desenvolvimento de novas ferramentas, como a ecocardiografia bidimensional feature tracking (2D-FTI), permite diagnosticar, de forma precoce, se há disfunção miocárdica em doenças cardíacas, inclusive as congênitas. O defeito septal ventricular (DSV) é a alteração congênita mais observada em felinos, no entanto pouco se sabe sobre a disfunção cardíaca nessa cardiopatia, especialmente em animais assintomáticos. O objetivo deste estudo foi avaliar, por meio do 2D-FTI, a deformação miocárdica ventricular esquerda pela mensuração dos índices ecocardiográficos strain (St) e strain rate (StR) radial, circunferencial e longitudinal, em gatos saudáveis e com DSV. Foram avaliados 12 gatos saudáveis e seis gatos com DSV para obtenção de St e StR em diversos segmentos miocárdicos. No sentido longitudinal, houve diferença estatística (P<0,05) para os segmentos septal basal, mediano e apical epicárdicos (P=0,0017; P<0,0001; P=0,0288), lateral mediano epicárdico (P=0,0327), septal mediano endocárdico (P=0,0035), lateral mediano endocárdico (P=0,0461), St epicárdico (P=0,0250) e St global (P=0,0382). Também houve diferença no segmento lateral mediano circunferencial endocárdico (P=0,0248), lateral mediano radial (St: P=0,0409; StR: P=0,0166) e posterior mediano radial (P=0,0369). O estudo evidenciou que, mesmo em animais assintomáticos com DSV, há redução na deformação miocárdica ventricular principalmente no sentido longitudinal, demonstrando maior vulnerabilidade dessas fibras.(AU)
The development of new tools, such as two-dimensional feature tracking (2D-FTI), allows early diagnosis of myocardial dysfunction in heart diseases including congenital heart disease. The ventricular septal defect (VSD) is the most frequently observed congenital abnormality in cats, however, little is known about cardiac dysfunction, especially in asymptomatic animals. The objective of this study was to evaluate the left ventricular myocardial deformation through 2D-FTI by the measurement of the radial, circumferential and longitudinal echocardiographic strain (St) and strain rate (StR) indices. Twelve healthy cats and six cats with VSD were evaluated to obtain St and StR in several myocardial segments. In the longitudinal direction, there was a statistical difference (P<0.05) for the epimyocardial basal septal, mid-septal, apical septal (P=0.0017; P<0.0001; P=0.0288), epimyocardial mid-lateral (P=0.0327), endomyocardial mid-septal (P=0.0035), endomyocardial mid-lateral (P=0.0461), St epimyocardial (P=0.0250) and St global (P=0.0382). There was also difference in the circumferential endomyocardial mid-lateral segment (P=0.0248), radial mid-lateral (St: P=0.0409; StR: P=0.0166) and radial mid-posterior (P=0.0369). The study showed that even in asymptomatic animals with VSD there is a reduction in ventricular myocardial deformation mainly in the longitudinal direction, demonstrating the fragility of these fibers.(AU)