Atypical fetal junctional ectopic tachycardia: a case report and literature review

Abstract

Background Junctional ectopic tachycardia (JET) is caused by ectopic rhythms, originating in the atrioventricular node, typically with heart rate between 200 and 250 bpm. Herein, we present a case of fetal JET with normal fetal heart rate and a review of nine cases. Case presentation A 32-year-old, gravida 2, para 1, woman in whom fetal JET could not be diagnosed prenatally because the fetal heart rate was within the normal range. The fetus was diagnosed with premature restriction of the foramen ovale, and a cesarean section was performed, owing to the right heart overload that was characterized by fetal ascites and abnormal fetal Doppler velocity. Postnatally, the female neonate was diagnosed with JET on a 12-lead electrocardiogram, which revealed a neonatal heart rate of 158 bpm with narrow QRS and atrioventricular dissociation. After failure to respond to amiodarone therapy, she was treated with flecainide, which controlled the JET rate from 120 to 150 bpm. Fetal tachycardia with ventriculo-atrial (VA) dissociation or 1:1 VA conduction with a shorter VA interval than that of atrioventricular reentrant tachycardia confirmed the diagnosis of fetal JET. Conclusions JET should be suspected even in the absence of tachycardia in patients with ductus venosus and pulmonary vein retrograde flow or tricuspid and mitral regurgitation without a cardiac anomaly, as tachycardia might sometimes be intermittent in cases of JET.

Unexplained fetal tachycardia: A case report

“…Most cases of fetal tachycardia have a heart rate of less than 200 bpm, which usually does not require treatment but requires close follow-up[ 1 , 2 ]. Approximately 10%–20% of cases of fetal tachycardia require referral to a fetal cardiologist for further evaluation, and persistent fetal tachycardia with congestive cardiac dysfunction or fetal edema requires intrauterine or postpartum treatment[ 3 , 4 ]. One report of FHR > 224 bpm indicated that the persistence of fetal tachycardia was not necessarily caused by fetal hypoxia, and the heart rate was controlled by metoprolol treatment after transfer to a higher-grade hospital[ 5 ].…”