Overview
This lecture explains atrial septal defects (ASDs) in pediatric patients, covering types, pathophysiology, signs and symptoms, complications, and nursing care.
What is an Atrial Septal Defect (ASD)?
- ASD is a hole in the wall (septum) between the right and left atria of the heart.
- Normally, there should be no connection between the upper chambers after birth.
- Small ASDs may be asymptomatic, but large ASDs cause significant problems.
- Prevalence: about 1 in 770 babies in the US are born with an ASD.
Types of ASDs
- Ostium secundum: most common, located in the middle of the atrial septum.
- Ostium primum: located near the bottom of the septum, close to the atrioventricular valves.
- Sinus venosus: located near the superior vena cava and right atrium.
- Patent foramen ovale (PFO): a type where fetal connection fails to close after birth.
Pathophysiology and Complications
- After birth, left-sided heart pressure is higher than right-sided, leading to left-to-right shunting in large ASDs.
- This increases blood flow to the lungs, causing pulmonary hypertension, heart failure, and risk of stroke.
- Over time, untreated ASDs can cause Eisenmenger's syndrome: shunt reversal (right-to-left), leading to cyanosis.
- Large ASDs can cause right atrial/ventricular enlargement and recurrent lung infections.
Signs and Symptoms ("HOLES")
- H: Heart failure and pulmonary hypertension (difficulty breathing, fatigue, feeding problems, crackles, edema).
- O: Often experiences lung infections due to lung congestion.
- L: Low growth rate/failure to thrive from poor feeding and increased energy needs.
- E: Extra heart sounds—mid-systolic murmur, wide fixed splitting of S2 at upper left sternal border.
- S: Stroke risk, especially with PFO or large ASD due to paradoxical emboli.
Nursing Interventions and Treatment
- Small ASDs are monitored; large ASDs may need surgical closure or catheter-based repair.
- Diuretics may be used if heart failure and fluid overload are present.
- Monitor nutrition, growth, heart rhythm (for dysrhythmias like atrial fibrillation).
- Assess respiratory status and prevent infections (immunizations, hygiene).
- Educate patients and families about signs of complications and infection prevention.
Key Terms & Definitions
- Atrial Septal Defect (ASD) — hole in the septum between right and left atria.
- Left-to-right shunt — blood moves from higher-pressure left atrium to lower-pressure right atrium.
- Pulmonary hypertension — high blood pressure in the lung arteries.
- Eisenmenger's syndrome — irreversible reversal of shunt to right-to-left, causing cyanosis.
- Patent foramen ovale (PFO) — fetal opening in atrial septum fails to close after birth.
- Mid-systolic murmur — heart murmur heard during middle of heart contraction.
Action Items / Next Steps
- Take the free quiz on atrial septal defects.
- Review types and locations of ASDs for exams.
- Monitor for symptoms and complications in practice scenarios.