Fetal supraventricular tachycardia

Objective: The diagnosis of fetal supraventricular tachycardia (SVT) which can be intermittent or continuous is established by 1:1 atrioventricular conduction in echocardiography, and heart rate between 220 and 240 bpm. We aimed to present a fetal SVT case characterized by the loss of variability and intermittent tachycardia attacks in non-stress test (NST). Case: The fetus at 32 weeks of gestation was diagnosed with SVT due to the loss of variability at NST, intermittent tachycardia attacks, 230 bpm at echocardiography and regular 1:1 AV conduction. Oral sotalol therapy was initiated to the mother. At the follow-up, spontaneous vaginal delivery was carried out at week 342/7. Upon observing SVT attack for five minutes at eight hour of the birth, oral digoxin therapy was initiated. No additional SVT attack was observed during 3 months of follow-up. Conclusion: Intermittent fetal SVTs may progress only by the loss of variability at NST during non-attack periods. We believe that it would be useful to follow-up cases closely who have normal biophysical profile except the loss of variability at NST in terms of fetal tachyarrhythmia.