Ebstein's Anomaly Associated with Cardiomyopathy

DURING the past decade definite progress has been made toward an understanding of the hemodynamic alterations and pathophysiologic aspects of Ebstein's anomaly of the tricuspid valve.1' 2 Moreover, an increased awareness of the characteristic clinical findings has resulted in an apparent increase in incidence of the disease. Largely as a result of careful pathologic studies, atypical forms of Ebstein's anomaly have been recognized. These include (a) a forme fruste characterized by minor tricuspid valve malformation with mild or clinically inapparent disease3 and (b) the association of Ebstein's anomaly with a variety of other congenital cardiac lesions. Defects of the atrial septum are common in Ebstein's anomaly 2 and should not be considered associated lesions. Rather they are an integral part of the fullblown syndrome, since they allow shunting of blood away from the poorly functioning right heart. In contrast, ventricular septal defects may be considered associated congenital cardiac lesions, since they have been described in only four patients 4-7 and markedly alter the clinical findings. Isolated case reports have described the association of Ebstein's anomaly with patent ductus arteriosus7,' 8pulmonary stenosis,3 dilated pulmonary artery,9 hypoplastic pulmonary artery,8 10 corrected transposition of the great vessels with 11 12 and without 13 14 ventricular septal defect, hypoplastic aorta with fetal coarctation,7 pulmonary stenosis with ventric-