The maternal exposure of digoxin and flecainide in relation to the safety and effectiveness in the treatment of non-hydropic fetal tachycardia.

Background: Sustained fetal tachycardia requires transplacental anti-arrhythmic therapy. Little is known about the dose-concentration-effect correlation and safety in the mother, fetus, and newborn.

Objective: This study evaluates the relationship between maternal dose of digoxin and flecainide therapy for fetal tachycardia, maternal and umbilical cord concentrations, and side effects.