Prenatal management of fetal supravevtricular tachycardia

Abstract

Introduction: Fetal cardiac arrhythmias are discovered in about 1% of fetuses and most of them are supraventricular tachycardia (SVT). Persistent tachycardia with a fetal heart rate (FHR) more than 220 bpm could lead into congestive cardiac failure and can manifests as non-immune fetal hydrops. With the rapid advancement in fetal echocardiographic skills, such arrhythmias can be diagnosed accurately during prenatal life by using M-mode echocardiogram and Doppler. Case 1: A 28 year old primigravida was referred from Jaffna due to fetal tachycardia and ascites detected at routine scan at 27 weeks. Detailed anomaly scan including cardiac evaluation was performed after admission to our unit and SVT with a heart rate of 278 bpm with hydrops fetalis found with no other gross anomalies. Mother was started on digoxin 0.25mg twice a day and changed in to sotalol 80mgtwice a day after 48 hours. Sotalol omitted and flicanide 100mg twice a day started after 4days. Because of persistently high FHR Cordocentesis done and 30µg of digoxin injected to umbilical vein and 4 days later amioderone 5mg injected. Subsequently FHR decreased to 137 bpm. Case 2: A 38 year old, mother of one was transferred from Badulla due to fetal tachycardia at 36 weeks. Scan at our unit revealed Ebstein anomaly of fetus lead to re-entral tachycardia. Atrial rate was 338 bpm and ventricular rate was 168 bpm. Baby delivered electively and admitted to SCBU. Discussion: Fetal SVTs may be associated with adverse perinatal outcome. Development of fetal hydrops is a poor prognostic factor and placental oedema reduces transfer of drugs to fetus. Early identification and intervention (before development of hydrops) will lead to better perinatal outcome.