Fetal echocardiography; basic and clinical considerations.

Present 2-D real-time and M-mode systems allow detailed studies of fetal left and right ventricular cardiac geometry and function. Antenatally, both ventricles are geometrically uniform. There is a curvilinear increase in left ventricular volume (Q1v), stroke volume (Q1v,s) and output (Q'1v) during the last trimester of pregnancy. At term a mean Q'1v of 126 +/- 11 ml kg-1 min-1 was found. Structural analysis of the fetal heart has resulted in the diagnosis of fetal congenital heart disease and cardiac dysrhythmias. Possibilities of antenatal medical treatment of fetal cardiac dysfunction are currently under investigation.