Which medication may be prescribed for a newborn with mild to moderate Ebstein's anomaly to reduce right ventricular afterload?

• A. Digoxin
• B. Furosemide
• C. Sildenafil
• D. Indomethacin

Answer: (C)

The key idea is lowering the resistance the right ventricle must pump against to improve right-sided blood flow. In Ebstein’s anomaly, the right ventricle is functionally small and works against pulmonary vascular resistance (PVR). When PVR is high, the RV has more difficulty ejecting blood into the lungs, leading to reduced pulmonary flow and worse systemic oxygenation from shunting. A medication that directly lowers PVR acts as a pulmonary vasodilator, easing RV afterload and improving forward flow.

Sildenafil fits this need because it inhibits phosphodiesterase-5, increasing cGMP in the pulmonary vasculature and causing vasodilation. This reduces PVR, lessens the RV’s afterload, and improves oxygenation in newborns with mild to moderate Ebstein’s anomaly.

The other options don’t target afterload in the same way. Digoxin enhances contractility without reducing pulmonary resistance. Furosemide mainly reduces preload to manage fluid status, not the afterload the RV faces. Indomethacin closes the ductus arteriosus, which could worsen systemic oxygenation by removing a potential pathway that supports circulation in these infants.