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[Echocardiographic findings in infants with transposition of the great arteries]
Insights
Echocardiography reveals age-related changes in infants with complete transposition of the great arteries (TGA). The right ventricle enlarges, while the left ventricle may narrow, potentially impacting outflow tracts without significant pressure gradients.
Area of Science:
- Pediatric Cardiology
- Diagnostic Imaging
- Congenital Heart Disease
Context:
- Complete transposition of the great arteries (TGA) is a critical congenital heart defect.
- Preoperative assessment is crucial for surgical planning in TGA.
- Echocardiography is a primary non-invasive imaging modality in pediatric cardiology.
Purpose:
- To evaluate age-related changes in cardiac dimensions and morphology in infants with TGA using echocardiography.
- To compare echocardiographic findings with contrast ventriculography and cardiac catheterization.
- To assess the development of left ventricular outflow tract obstruction in TGA.
Summary:
- Echocardiography in 48 infants with TGA showed progressive right ventricular enlargement and left ventricular dimension decrease with age.
- The ratio of left ventricular end-diastolic dimension to right ventricular end-diastolic dimension decreased significantly.
- Increasingly frequent observations of systolic anterior mitral valve motion and pulmonary valve closure were noted with age, suggesting potential left ventricular outflow tract compromise.
Impact:
- Echocardiography provides valuable qualitative insights into cardiac remodeling in TGA during the first year of life.
- Findings suggest that while left ventricular outflow tract narrowing occurs, it may not always result in hemodynamically significant obstruction.
- This study highlights echocardiography's role in characterizing morphological changes in TGA, complementing other diagnostic methods.
Abstract:
Preoperative echocardiographic examinations were performed in 48 infants with complete transposition of the great arteries (TGA). The patients were classified according to age into 4 groups: group A (n = 24) 1 to 4 days; group B (n = 7) 14 days to 3 months; group C (n = 8) 3 to 6 months; group D (n = 9) 6 to 12 months. The right ventricular end-diastolic dimension (RVED) was significantly increased above normal in all but group B. The left ventricular end-diastolic dimension (LVED) was significantly decreased only in group D. During the first year of life, the mean LVED remained essentially unchanged while the mean RVED clearly increased. The ratio of the LVED/RVED as well as the relationship between the dimensions of the left ventricular outflow tract (LVO) and the pulmonary artery decreased significantly. With increasing age systolic anterior motion of the mitral valve, diastolic contact of the anterior mitral valve leaflet with the interventricular septum (IVS) and systolic closure of the pulmonary valve leaflets were observed more frequently. In some cases, both echocardiographically and contrast-ventriculographically, the LVO appeared to demonstrate obstruction but cardiac catheterization revealed a meaningful pressure gradient (LVO/PA) only in 3 patients in group D. In the course of the first year of life, these patients with TGA showed an increasing size of the right ventricle which assumed a rounded shape due to bulging of the IVS into the left ventricle. The left ventricle tended to become sickle-shaped with narrowing of the LVO which did not necessarily create a hemodynamically-effective obstruction. Thus, in patients with TGA, echocardiography rendered typical, qualitative findings, comparable with contrast ventriculography, albeit without hemodynamic inferences.