Children's Hospital Colorado

Research background

Fetuses with maternal Sjogren’s antibodies (anti-SSA antibodies) have a 4 percent risk of developing complete atrioventricular block (CAVB). The risk of perinatal death even if paced in the first day of life is six- to eleven-fold higher if the fetus:

  • Developed CAVB at <20 weeks of gestation
  • Had a fetal heart rate <55 beats per minute
  • Developed heart failure

Research case report

The 18 6/7-week-old fetus of a healthy 21-year-old presented with a fetal heart rate (FHR) of 60 bpm and CAVB. Two days prior to the visit, the FHR and rhythm were normal.

Although she was asymptomatic and had no history of Sjogren’s syndrome, the mother was found to have very high anti-SSA antibodies.

In an unsuccessful attempt to reverse the CAVB, the mother received a dose of IV immune globulin and dexamethasone. At 26 weeks, terbutaline was prescribed to increase the FHR, which had fallen to <55 bpm. Despite treatment, at 36 weeks the FHR fell to 47 bpm and heart failure developed.

After a multi-disciplinary team meeting at Children’s Hospital Colorado including neonatology, pediatric surgery, cardiothoracic surgery, anesthesia and fetal cardiology, the team decided to use an EXIT (Ex Utero Intrapartum Treatment) delivery to ventricular pacing.

A surgeon operates wearing a clear face shield

A novel delivery strategy for complete atrioventricular block with severe bradycardia

The EXIT procedure allows life-saving fetal/neonatal interventions while maintaining uteroplacental circulation. The goal of the EXIT procedure is to provide a successful transition to extra-uterine life.

2013 First EXIT to Cardiopulmonary Bypass and Atrial Septectomy for Hypoplastic Left Heart Syndrome with Intact Atrial Septum
2016 First EXIT to Ventricular Pacing for Fetal Complete AV Block

Research procedure

Drs. Henry Galan and Ahmed Marwan of the Colorado Fetal Care Center at Children’s Colorado performed the EXIT procedure while Dr. Bettina Cuneo, also of the Colorado Fetal Care Center, monitored FHR and cardiac function. While the infant was on placental bypass, Dr. Max Mitchell, pediatric cardiothoracic surgeon, placed temporary epicardial ventricular pacing leads successfully. The infant was then delivered and successfully transitioned to postnatal life.

Here are additional procedure details:

  • Mother and fetus were anesthetized with epidural, inhalational and total IV anesthesia
  • Fetal head, chest and upper extremities delivered through low traverse uterine incision
  • The fetus received an infusion of isoproterenol and epinephrine prior to pacemaker insertion
  • The fetus was paced at 70 bpm 10 minutes after the pacemaker incision was made
  • The fetus was delivered 55 minutes after the Ex Utero Intrapartum Treatment (EXIT)

At 3 days old, permanent epicardial left atrial and left ventricular pacing leads were placed. The baby was extubated on the second post-operative day, discharged from cardiac intensive care at seven days. She is currently 7 months old and thriving.

Yellow circle with white words that say "Collaboration means better care, outcomes"

Research conclusion

The role of the Ex Utero Intrapartum Treatment to temporary ventricular pacing for the fetus with CAVB must be further defined and patients must be selected carefully. This “rescue” pacing may provide an option for the most fragile patients with CAVB: fetuses at high risk for in utero demise, but too premature for delivery and too small for ECMO.

The paper appeared in the journal Fetal Diagnosis and Therapy.