Myocardial dysplasia in a 3rd-trimester fetus. An ultrasound and pathologic study.

Arrested myocardial development, often described as spongiosum heart, has been reported in association with obstructive semilunar valve disease and, much more rarely, as a primary disease in adolescents and adults. To our knowledge, this condition has never been diagnosed in utero. We describe the echocardiographic and pathoanatomic findings of the 1st case of myocardial dysplasia detected in utero by ultrasound. A 28-year-old woman, gravida 2, para 1, was referred to our unit at 34 weeks of gestation due to severe fetal hydrops. On echocardiography, we observed gross fetal cardiomegaly (particularly of the septal and ventricular myocardium), an unusually bright myocardial echostructure, thick trabeculations in both ventricular chambers, and severe loss of myocardial contraction. There were normal ventriculoarterial connections and no signs of obstructive semilunar valve disease. After fetal death, necropsy confirmed the presence of spongiosum heart and the diagnosis of myocardial dysplasia--which term best describes this disorder in its various temporal expressions. Because this condition has never before been observed prenatally, no consideration has been given to intrauterine management. We recommend that fetal cardiac function be monitored echocardiographically whenever a pregnant patient has a positive family history of this disease. There is a possibility that the life of the affected fetus might be prolonged beyond the gestational period by avoiding intrauterine cardiac decompensation, through early delivery. We recommend further that the parents of these children be advised of the risks associated with future pregnancies. Little is known about the pattern of inheritance of myocardial dysplasia, but the disorder appears to be familial. Therefore, the possibility that it may recur within the same generation must be taken into account.