Atrial Septal Defect (ASD)

Presentation

• Often asymptomatic in the neonatal period
• Soft systolic ejection murmur at the upper left sternal border
• Widely split and fixed second heart sound (S2) - rare in neonates
• Incidental finding on echocardiogram for other indications

Initial Workup

• Echocardiogram (to identify size, location, and direction of shunt)
• Electrocardiogram (ECG) - may show right ventricular hypertrophy or right axis deviation
• Chest X-ray - may show mild cardiomegaly in large defects

Management & Counseling

• Observation (most small secumdum ASDs close spontaneously by 1-2 years of age)
• Routine pediatric follow-up to monitor for signs of heart failure (rare)
• Cardiology follow-up at 6-12 months for repeat echocardiogram if moderate-large

Extended Pharmacology & Critical Care

• Alprostadil (PGE1) continuous infusion: Start at 0.05 to 0.1 mcg/kg/min; monitor strictly for apnea, hyperthermia, and extreme vasodilation.
• Milrinone loading dose 50 mcg/kg over 15 mins (only if stable blood pressure), followed by 0.33 to 0.75 mcg/kg/min infusion.
• Strict I&O monitoring; maintain urine output > 1-2 mL/kg/hr using indwelling catheter if necessary.
• Maintain hematocrit > 35-40% via PRBC administration to optimize oxygen delivery in cyanotic lesions.
• Nursing: Q1 hour blood pressure monitoring (arterial line preferred), monitor for feeding intolerance indicating gut hypoperfusion.

Standardized Discharge & Follow-Up Criteria

• Adequate weight gain explicitly > 15-30g/day over a continuous 3-5 day period.
• Maintenance of temperature in an open crib with standard clothing for 48 hours.
• Successful completion of the 90-120 minute Infant Car Seat Challenge.
• Caregiver successfully completed CPR training, rooming-in, and independent medication administration.
• Referrals placed for High-Risk Infant Follow-Up Clinic, Early Intervention (PT/OT), and appropriate sub-specialists.

Diagnostic & Management Algorithm

• ASD Algorithm: [START] Suspected ASD -> [ACTION] Echocardiogram -> [DECISION] Size & Symptoms? -> [YES] Large/CHF: Diuretics -> [NO] Small/Asymptomatic: Observe -> [GOAL] Surgical closure at 3-5 years if unclosed

References

1. Martin SS, Shapiro EP, Mukherjee M. Atrial septal defects - clinical manifestations, echo assessment, and intervention. Clin Med Insights Cardiol.