Fetal cardiomyopathies: pathogenic mechanisms, hemodynamic findings, and clinical outcome.

BACKGROUND: Although the prenatal diagnosis of most fetal structural heart defects and dysrhythmias has been described, there is a paucity of information about cardiomyopathies (CMs) in prenatal life. METHODS AND
RESULTS: To determine the pathogenic mechanisms, hemodynamic findings, and outcome of fetal CM, we reviewed the fetal echocardiograms and perinatal histories of 55 affected fetuses. Dilated CM was diagnosed in 22 cases, including 2 with congenital infections, 5 familial cases, 6 with endocardial fibroelastosis related to maternal anti-Ro/La antibodies, and 9 idiopathic cases. Thirty-three had hypertrophic CM, 7 associated with maternal diabetes, 2 with Noonan's syndrome, 2 with alpha-thalassemia, 18 with twin-twin transfusion syndrome, 1 with familial hypertrophy, and 3 with idiopathic hypertrophy. Systolic dysfunction was present in all cases of dilated CM and 15 cases of hypertrophic CM. Diastolic dysfunction was present in 19 of 30 fetuses with assessment of diastolic function parameters. Significant mitral or tricuspid valve regurgitation was seen in 32 cases. Eight fetuses were hydropic and 23 had signs of early hydrops. Seven pregnancies were terminated. Of 46 continued pregnancies with follow-up, 29 (63%) died perinatally. The presence of systolic dysfunction, diastolic dysfunction, and significant atrioventricular valve regurgitation were identified as risk factors for mortality. By multiple logistic regression, diastolic dysfunction was associated with an 8-fold increased risk relative to the other parameters.
CONCLUSIONS: Fetal CM has a broad spectrum of intrinsic and extrinsic causes. A poor outcome is observed in many affected fetuses. Diastolic dysfunction in fetal CM is associated with the highest risk of mortality.