Prenatal Management and Outcome of Junctional Ectopic Tachycardia and Hydrops

Abstract

Fetal dysrhythmias are reported in approximately 1-2% of all pregnancies and are a relatively common reason for referral to fetal medicine centers1-3. Fetal tachycardia is a serious condition in which the fetus is at risk of congestive heart failure and the subsequent development of hydrops1-4. This situation is associated with significant morbidity and mortality1-4. In general, the diagnosis and assessment of these dysrhythmias can be accurately made using high-resolution 2-D ultrasound using M mode and Doppler assessment of the relationship between the atrial and ventricular contractions5. Junctional ectopic tachycardia (JET) is a rare form of fetal tachyarrhythmia, which usually occurs in the setting of surgery for congenital heart disease6. In addition, a congenital variety of JET not related to surgery has also been described. While post-surgical JET has a mortality up to 14%, congenital JET has a mortality up to 34%6. The congenital form of JET has rarely been reported during the prenatal period7,8. We describe a case in which the diagnosis was suspected in utero in a patient referred to our Department because of the presence of important fetal ascitis. The diagnosis was based on the evidence of moderate tachyarrhythmia episodes without 1:1 AV relationship and intermittent absence of atrial contraction wave consistent with atrioventricular (AV) dissociation, together with ductus venosus reverse diastolic wave indicating mild cardiac failure. JET diagnosis was confirmed after birth.