Overview
This lecture covers atrial septal defects (ASD) in pediatric patients, including types, pathophysiology, clinical signs, risks, and nursing interventions.
Definition and Epidemiology
- An atrial septal defect (ASD) is a hole in the wall (septum) between the right and left atria of the heart.
- 1 in every 770 babies in the US is born with an ASD.
- Small ASDs often cause few problems; large ASDs can lead to serious complications.
Types of ASDs
- Ostium secundum: Most common, located in the middle of the atrial septum.
- Ostium primum: Found at the lower part of the septum near the atrioventricular valves.
- Sinus venosus: Located near the superior vena cava and right atrium.
- Patent foramen ovale (PFO): A hole that did not seal after birth, increasing stroke risk.
Pathophysiology
- Normally, the left side of the heart has higher pressure than the right after birth.
- In large ASDs, blood shunts from left atrium to right atrium (left-to-right shunt).
- Increased blood flow to the lungs leads to pulmonary hypertension and stresses the right heart.
- Chronic overload can cause heart failure, arrhythmias, and increased stroke risk.
- Untreated severe cases lead to Eisenmenger's syndrome (reversal of shunt, cyanosis).
Signs and Symptoms ("H-O-L-E-S")
- Heart failure and pulmonary hypertension: decreased cardiac output, fatigue, breathing difficulty, poor feeding, failure to thrive.
- Often has recurrent lung infections due to congestion.
- Low growth rate caused by poor feeding and high energy needs.
- Extra heart sounds: mid-systolic murmur and wide, fixed S2 splitting.
- Stroke risk increases due to blood clots passing through the ASD.
Diagnosis and Treatment
- Diagnosis via echocardiogram (non-invasive heart ultrasound).
- Small ASDs: often monitored only; large ASDs: may need diuretics, surgery, or catheter closure in early childhood.
- Monitor nutrition, heart rhythm, respiratory status, and infection risk.
- Education on vaccines and infection prevention is important.
Key Terms & Definitions
- Atrial Septal Defect (ASD) — a hole between the heart's right and left atria.
- Left-to-right shunt — blood moves from higher pressure left atrium to right atrium.
- Pulmonary Hypertension — high blood pressure in lung arteries due to excess blood flow.
- Eisenmenger's Syndrome — reversal of blood shunting leading to cyanosis.
- Patent Foramen Ovale (PFO) — a remnant hole from fetal circulation not closed after birth.
Action Items / Next Steps
- Take the free quiz on atrial septal defects.
- Review signs, symptoms, and treatment options for ASD.
- Study types and locations of ASD for exams.