Diagnostic criteria of interatrial defects: a single gate pulsed Doppler echocardiographic study

Functional closure of the oval foramen occurs during the first days of life. Nevertheless, range-gated pulsed Doppler echocardiography shows a transatrial flow pattern in many newborns. In this situation, cross-sectional echocardiography often fails in differentiating the valve-incompetent oval foramen from an atrial septal defect. In order to establish Dopplersonographic criteria for these diagnoses, we performed a prospective echocardiographic and pulsed Doppler study in 34 newborns with valve-incompetent oval foramen and in 30 children with atrial septal defect. We could not find any significant difference of flow pattern in either group, although a so-called "flap" signal could be demonstrated in 73.5% of the patients with an oval foramen, but in only 23% of the children with atrial septal defect. We suggest this feature reflects a distinct movement of the flap of oval foramen which passively follows the different interatrial pressure-flow dynamics. Nevertheless, this sign was insufficiently constant to prove presence of an oval foramen and not that specific to exclude an atrial septal defect. We conclude, therefore, that the precise nature of interatrial defects cannot be differentiated by single gate pulsed Doppler echocardiography.