Fetal Arrhythmies
The persistents major ipo or ipercinetic arrhythmies could constitute
a condition of "cardiological fetal emergency" and if
not in relief and promptly takes care of could conduct the fetus to heart
failure and intrauterine death .The worse prognosis when the arrhythmy
joins congenital heart disease (CHD).
The most common form of ipercinetic arrhythmies is the supraventricular
paroxysmal form that in the 10% of the cases join to structural CHD. The
form that imposes a medical treatment the incessant one that it join to
heart failure and/or CHD. Less frequent the atrial flutter or fibrillation
or ventricular tachicardia.
Between the ipocinetic arrhythmies the most remarkable is the complete
a-v block whose prognosis tied to the ventricular frequency . When the
ventricular frequency is < to 50 p.m. sever heart failure is the rule
and having tried a trans-abdominal pacing without positive effect. This
therapeutic approach would be desirable but for a prolonged stimulation
the risk of infections fetal is very elevated . The literature brings again
cases sporadic treatises without success with beta stimulating agent (
isoproterenol,ritrodin etc)
The most commonly drugs used are listed in the following chart.
| Transplacental Treatment of Fetal Arrhythmies | ||
| Drugs | ose | Maintenance dose |
|---|---|---|
| Digoxin | g. os0.5 – 2 mg. e.v. | 0.25 – 1 mg/die os |
| Propranolol | mg e.v. ( 0.04 mg/kg ) | 80 – 160 mg/die os |
| Verapamil | e.v. | 240 – 360 mg/die os |
| Procainamid | e.v. | 3 – 4 gr/die os |
| Quinidine | os | 1-2 gr/die os |
| Flecainid | e.v. | 300 mg/die os |
| Amiodarone | os | 600 mg/die os |
| Betamimetics | **) | without effects. |
**) Fetal heart block may be treated with a loading test dose of Salbutamol e.v. 80 mg/L dextrose 4% solution starting
with 4 micrograms/min and increased to 64 micrograms/min during the trial and
followed by Salbutamol os 8 mg twice a day until delivery.(Groves and coll.Circ.92:3394:1995)
In heart block with maternal anti-Ro and/or anti La proteins autoantibodies
has been used Dexamethasone to the mother dosing 4 mg os once a day mantained until delivery,
(Copel et al.:Am J obstet Gynecol 1384:173:1995)
