Development of a new lead for in utero fetal pacing.
BACKGROUND
The results from preliminary studies on fetal pacing preclude an application to the human fetus. The purpose of this study was to evaluate the feasibility of acute fetal cardiac pacing following ultrasound-guided epicardial anchorage of a new pacing lead dedicated to the fetal heart.


METHODS
In 12 pregnant ewes, a needle was placed in contact with cardiac chambers under echo-guidance. Using the lumen of the needle, a 3-Fr pacing lead was advanced and fixed on the cardiac wall using a built-in screw. Pacing was attempted using an external pacing system.


RESULTS
Lead insertion was successful in all but one. In the first fetus, the needle was advanced too far into the right ventricle leading to pericardial bleeding. The fetal heart rate was overdriven in all at 220/ min. After assessment, pacing lead was unscrewed and retrieved without any complication. Pregnancy was electively interrupted in six animals. The other six fetuses were delivered vaginally after uneventful pregnancy and autopsy at day 3 did not show any significant injury.


CONCLUSIONS
Transcutaneous echo-guided fetal acute pacing is feasible using a specially designed lead. Additional refinement of both the equipments and the operative technique are needed before considering permanent pacing in the human fetus.
Boudjemline
Younes
Y
Service de Cardiologie Pédiatrie, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, and Faculté de Médecine Necker-Enfants Malades, Université Paris V, Paris, France.
Rosenblatt
Jonathan
J
de La Villeon
Grégoire
G
Bénifla
Jean-Louis
JL
Bonnet
Damien
D
Jouannic
Jean-Marie
JM
D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004566:Electrodes; D004567:Electrodes, Implanted; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D010138:Pacemaker, Artificial; D011247:Pregnancy; D012756:Sheep