[Fetal arrhythmias. Differential diagnosis, clinical significance and prognosis].

Between June 1979 and June 1984 the authors observed 40 fetal arrhythmias in 11,122 births (0.36%). Initially there were problems of differential diagnosis with cardiotokography and fetal abdominal ECGs. However, these problems were surmounted with real-time sonography, supplemented with split-image echocardiography (M-mode technique) with video recording. In three-quarters of the cases supraventricular and ventricular extrasystoles were found. These forms of arrhythmias were clinically harmless. Follow-up examinations of the children confirmed the favorable long-term prognosis. One-quarter of the arrhythmias were high-risk cases. Supraventricular tachycardias, total AV block, sinus tachycardia and bradycardia, and congenital atrial fibrillation were found. There were five cardiac abnormalities in this group. Heart failure occurred in six fetuses and neonates. Four of ten infants died. Three infants remained in pediatric cardiologic care. In the light of the authors' experience, it is still too early to invest great hope in intrauterine treatment of the fetus. Intrauterine diagnosis at the earliest possible time and intensive cardiologic care, starting immediately after birth, can improve the prognosis in cases with high-risk arrhythmias.