Pediatrics · Topic 23 of 42
Atrial Septal Defect (ASD)
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Atrial Septal Defect (ASD)
An opening in the wall between the atria shunts blood left to right, overloading the right heart and lungs while the child stays pink. Often silent in childhood; left open, a large ASD causes problems in adulthood.
Why it happens
Blood shunts left to right at the atria — right heart overloaded
Ostium secundum (center of the septum) is the most common type, about 75% of ASDs; ostium primum and sinus venosus are the other main types. About 13 of every 10,000 US babies are born with an ASD.
What you'll see
Often silent — found when a murmur is heard at a routine exam
The split S2 and murmur may be absent in infants; sometimes the ASD is not found until adulthood. A large shunt can add a low-pitched diastolic murmur at the lower sternal border.
If a large ASD is never closed
The problems appear in adulthood
Pulmonary hypertension from an unrepaired ASD can appear by the 30s or 40s; Eisenmenger reversal is rare and usually after age 40.
Red flags
Device erosion is rare (about 0.1–0.3%) but can cause cardiac tamponade, usually in the first days, rarely years later.
Treatment
Follow with echocardiograms instead of repairing right away
Many close on their own in early childhoodTranscatheter device from a groin vein — no open-heart surgery
Surgical patch closure
About 6 months, at the dose the prescriber sets
Stop and call for fever, flu-like illness or chickenpox exposure (Reye syndrome)No strenuous activity or contact sports for the set period
Types, sizes and timing
Nursing priorities
PFO or ASD?
A PFO is the fetal opening that never sealed — not a true ASD
| PFO | ASD | |
|---|---|---|
| What it is | The fetal foramen ovale that failed to seal after birth | An opening in the wall between the atria |
| A true ASD? | No | Yes |
| How common | About 1 in 4 people | About 13 in 10,000 babies |
Teach the family
Dental prophylaxis continues past 6 months only if a leak remains after closure.
A fixed, widely split S2 plus a soft murmur at the upper left sternal border points to an ASD. Often silent in childhood — left open, a large ASD brings atrial fibrillation and stroke in adulthood.
Sources · About Atrial Septal Defect (CDC) · Atrial Septal Defect (MedlinePlus) · Atrial Septal Defect (Merck Manual Professional) · Atrial Septal Defects: From Embryology to Pediatric Pulmonary Hypertension (PMC) · ASD Closure in the Heart Catheterization Lab (AboutKidsHealth, SickKids) · Reye Syndrome (MedlinePlus) · Patent Foramen Ovale (MedlinePlus) · Antibiotic Prophylaxis Prior to Dental Procedures (ADA) · Prevention of Viridans Group Streptococcal Infective Endocarditis (AHA, Circulation 2021) · Late Erosion of an Amplatzer Septal Occluder (PMC) · Follow your facility's protocol for care after ASD device closure.
Atrial Septal Defect (ASD)
An atrial septal defect, or ASD, is an opening in the wall between the heart's atria that lets blood shunt left to right, overloading the right heart and lungs while the child stays pink. It is often silent in childhood and is usually found when a murmur is heard at a well-child or school exam, sometimes not until adulthood. The hallmark findings are a fixed, widely split second heart sound that does not change with breathing, plus a soft systolic ejection murmur at the upper left sternal border. Small secundum defects often close on their own and are followed with echocardiograms. Most secundum ASDs are closed with a catheter-placed device from a groin vein; other types need a surgical patch. After device closure the child takes aspirin for about six months, stops it and calls for fever, flu-like illness or chickenpox exposure, and reports chest pain, fainting or a racing heartbeat right away. Left open, a large ASD can cause atrial fibrillation, pulmonary hypertension and stroke in adulthood. A patent foramen ovale is not a true ASD.
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