Ex utero Intrapartum Treatment to Ventricular Pacing: A Novel Delivery Strategy for Complete Atrioventricular Block with Severe Bradycardia.

Fetuses with anti-SSA-mediated complete atrioventricular block (CAVB) are at high risk for perinatal death if they present at <20 weeks of gestation and develop ventricular rates of <55 beats per minute (bpm), cardiac dysfunction, or hydrops [Izmirly et al.: Circulation 2011;124:1927-1935; Jaeggi et al.: J Am Coll Cardiol 2002;39:130-137; Eliasson et al.: Circulation 2011;124:1919-1926]. After our experience with two such fetuses who died with pulseless electrical activity despite being paced within 30 min of birth, we performed an ex utero intrapartum treatment procedure to ventricular pacing on a 36-week CAVB fetus with cardiac dysfunction, mild hydrops, and a ventricular rate of 46 bpm. While still on placental bypass, temporary epicardial ventricular pacing leads were successfully placed; the infant was delivered and made a successful transition to postnatal life. This approach can improve the 11-fold increase in mortality for the preterm fetus with long-standing CAVB, severe bradycardia, and heart failure.