An atrial septal defect (ASD) is a hole in the wall between the two upper chambers of the heart, most often the secundum type. Blood flows from left to right and overloads the right heart and lungs; small defects may close on their own, but large ones can cause arrhythmias, heart failure and pulmonary hypertension in adulthood.
Key symptoms
- Often no symptoms in childhood
- Shortness of breath and fatigue with exertion in adults
- Palpitations from atrial fibrillation or flutter
- Frequent chest infections in children
- Stroke from a clot crossing the defect (paradoxical embolism)
What you find on exam
- Wide, fixed split of the second heart sound
- Soft systolic ejection murmur at the left upper sternal border from extra pulmonary flow
- Right ventricular heave
- Late cyanosis if the shunt reverses (Eisenmenger syndrome)
Tests
- Echocardiogram with bubble study; transesophageal echo to size the defect
- ECG: right axis deviation and incomplete right bundle branch block
- Chest X-ray: enlarged right heart and prominent pulmonary arteries
- Cardiac MRI or catheterization to measure the shunt and lung pressures
Treatment basics
- Watch small defects; many close by age 2
- Close defects that enlarge the right heart, by catheter device or surgery
- Do not close if severe fixed pulmonary hypertension
- Treat arrhythmias and heart failure
- Aspirin for some months after device closure
Red flags
- Cyanosis or low oxygen saturation
- Stroke or TIA in a young patient
- Fainting or chest pain suggesting pulmonary hypertension
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.