Congenital heart disease
Atrial septal defects (ASD) are one of the most frequent congenital heart diseases in the adult patient. Atrial septal defects are classified according to site of the defect. The three types are: (1) ostium secundum, (2) ostium primum and (3) sinus venosus. In clinical practice the secundum defect is the most common type of atrial septal defect which is located in the site of foramen ovale. Two-dimensional echocardiography can directly demonstrate this defect in the middle portion of the atrial septum (Figure 4.1). However, in normals, a dropout of atrial septal echo is sometimes observed. Therefore, this finding should not be used as a definitive diagnostic criterion. In addition, the right ventricular and pulmonary artery enlargement with abnormal IVS motion due to right ventricular volume overload are present (Figure 4.2). Using M-mode echocardiography, the IVS motion is usually paradoxical or exhibits flattening (Figure 4.3), but in rare cases normal IVS motion can also occur (Figures 4.5). In primum type atrial septal defect, the defect is located in the inferior portion of atrial septum close to the atrioventricular valves (Figure 4.4), and mitral valve cleft can also occur (Figure 4.6). In sinus venosus type, the atrial defect cannot usually be identified by two-dimensional echocardiography and right ventricular volume overload may be the only finding. Mitral valve prolapse is sometimes associated with an atrial septal defect and can produce mitral regurgitation (Figure 4.7). Using pulsed Doppler and/or color flow mapping, it is possible to illustrate the left-to-right shunt across the defect from the parasternal four chamber view (Figure 4.8 and also Figure 11.28). A better angle to the flow can be usually obtained from the subcostal window which demonstrates more clearly the laminar left-to-right shunt flow (Figure 4.9). The increased flow volume in the right atrium results in augmented flow across the tricuspid and pulmonary valve, and higher than normal peak velocities are recorded. We can estimate the degree of the shunt from Qp/lQs assessment by pulsed Doppler derived left and right ventricular stroke volume (Figure 4.10).
KeywordsCongenital Heart Disease Septal Defect Atrial Septal Defect Ventricular Septal Defect Ventricular Septal Defect
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