[Idiopathic dilatation of the right atrium diagnosed in utero].

It is described one case of extreme right atrium dilatation detected in utero, as an isolated abnormality. Ebstein's anomaly was first suspected because in-utero tricuspid regurgitation detected with Doppler two dimensional echocardiography. Soon after birth and thereafter no tricuspid regurgitation could be find and no symptoms are present, despite the giantly dilated right atrium. The aetiology of this abnormality is discussed and the benign course emphasized.