Fifty fetuses referred to the Polish Mother's Memorial Hospital for fe
tal echocardiography between January 1, 1991 and June 1, 1995 were eva
luated. The mean fetal gestational age at the time of diagnosis of arr
hythmia was 34.1 weeks, and the mean gestational age at the time of de
livery was 38.7 weeks. Checkup echocardiographic examinations were per
formed every 10-14 days, for a mean 2.4 studies per fetus. In most cas
es (48/50, 96%), premature atrial contractions were present during the
first echocardiography examination. The fetal heart study was normal
in 30 cases; in 7 (14%) there was tricuspid valve regurgitation, in 7
(14%) an atrial septal aneurysm, in 4 congenital heart defects, in 1 m
yocardial hypertrophy, and in 1 disproportion in the four-chamber view
. Of the 50 fetuses, 43 underwent regular echocardiographic monitoring
alone; in 7 cases, based on the presence of additional echocardiograp
hic findings, pharmacotherapy was applied (digoxin, verapamil, or both
). Three neonates died after delivery owing to malformations in two ca
ses (one critical aortic stenosis, one spina bifida plus hygroma colli
) and due to myocarditis in one case. In six of seven newborns treated
in utero, myocarditis was diagnosed after birth (including the one wi
th neonatal demise). Most of the newborns were in good condition after
birth, their mean Apgar score being 8.6 and the mean birth weight 325
9 g. We concluded that most extrasystoles represent an isolated anomal
y, not affecting the fetal condition. Their presence should not influe
nce the obstetric care and may require only echocardiographic monitori
ng. In most of our cases the premature contractions subsided after bir
th, although sometimes they preceded fetal supraventricular tachycardi
a or appeared after congenital myocarditis.