Management of fetal supraventricular tachyarrhythmia - case report

The conduction system of the fetal heart is defined by the16th week of gestation when it matures and normally produces a regular rhythm and rate between 110 and 160 beats per minute (bpm) for the remainder of the pregnancy. Deviations from these parameters are fetal arrhythmias. They are diagnosed in 2% of unselected pregnancies. They are mostly benign and transient but some of them are persistent and associated with structural defects or can cause heart failure, fetal hydrops and intrauterine death. Routine prenatal care includes screening for fetal arrhythmias in the second and third trimester with fetal ultrasound examinations which include a view of the four cardiac chambers and both ventricular outflow tracts. The fetal outcomes are improved upon appropriate antepartum diagnosis and care. Here we present a pregnancy and multidisciplinary management, prenatal evaluation and intervention with maternal transplacental treatment of a 28-year-old female, gravida II, para II, in 28+5 weeks of gestation with fetal arrhythmia, in tertiary university hospital. She had a history of previous caesarean section, in the 40th week of gestation due to an infection of the synus pylonidalis. We confirmed suspected fetal arrhythmia as supraventricular tachyarrhythmia without fetal hydrops, based on the ultrasound doppler M mode imaging, and started transplacental administration of antiarrhythmyc agent, digoxin. It has been considered the first line agent for treatment of fetal supraventricular tachycardia but higher maternal doses are required to maintain a therapeutic serum level. We converted fetal heartbeat into normal sinus rhythm after three days of administration of digoxin. We continued to monitor the fetus once a week with controlling levels of digoxin and electrolytes in maternal blood until the end of the pregnancy at 38+6 weeks of gestation.