Abstract 5715: Development Of A Temporary Lead For In Utero Pacing: A New Approach For Cardiac Interventions In Fetuses
Background: Cardiac fetal intervention has been applied to human. It is presently limited to
the dilatation of obstructive valvular diseases and
the creation or dilatation of atrial septal defect in fetuses with hypoplastic left heart syndrome and restrictive atrial septal defect.
In this study, we propose a new application of fetal intervention represented by fetal pacing using a specially designed implantable pacing lead in the fetal lamb.
Methods and results: In twelve pregnant ewes (110 –112 days’ gestation), a 17 Gauge needle was placed in contact with cardiac chambers under echo-guidance. Using the lumen of the needle, a 3Fr unipolar pacing lead was advanced and fixed on the cardiac wall using a built-in screw. Pacing was, then, attempted using an external pacing system. Assessment of pacing was confirmed using ultrasound modalities. Pacing lead insertion was successful and uncomplicated in all 15 attempts (atrial and/or ventricular wall respectively n=3 and12) excepted one. In the first fetus, the needle was advanced too far into the right ventricle leading to pericardial bleeding after the retrieval of the needle. The fetal heart rate was overdriven in all at 220/min using the lead. After assessment, pacing lead was unscrewed and retrieved without any complication. Pregnancy was electively interrupted in 6 animals. The other six fetuses were delivered vaginally after an uneventful pregnancy and autopsy at day 3 did not show any significant injury.
Conclusion: Echo-guided fetal pacing is feasible using a specially designed lead. It enlarges present indications of human fetal cardiac interventions.