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Atrial Septal Defect
Cardiac
Atrial Septal Defect KEY FACTS
TERMINOLOGY
CLINICAL ISSUES
• ASD: Defect(s) in cardiac atrial septum; may be isolated anomaly or associated with other congenital heart lesions • L → R shunt: Blood from left heart bypasses systemic circulation to enter right heart ○ Most ASD sequelae related to long-term L → R shunting • Types of ASD ○ L → R shunts: Ostium secundum (70-90%), ostium primum, sinus venosus, unroofed coronary sinus defects ○ Patent foramen ovale only allows R → L shunting, usually transient given normal atrial pressures – Increased stroke risk; unclear migraine association
• ASD: 10% of congenital heart disease (CHD) in children, yet 30% of CHD in adults • Secundum ASD: Majority of patients asymptomatic; detected due to murmur or other medical work-up ○ Spontaneous closure occurs in many children ○ Rarely presents in childhood with failure to thrive, respiratory infection, tachypnea ○ Subtle symptoms more likely in 2nd decade, though large defects frequently do not present until adulthood – Fatigue, exercise intolerance, syncope, shortness of breath, palpitations – ASD leading to severe pulmonary hypertension: Median age of detection is 51 years ○ Repair indicated if shunt ratio > 1.5:1 or defect > 10 mm – Percutaneous closure with occlusion device • Primum/atrioventricular septal defect more severe; requires early surgical repair • Sinus venosus ASDs require surgery for complex anatomy
IMAGING • L → R shunting leads to chronic volume overload of right heart, eventual enlargement of RA, RV, & PA ○ Secondary findings & symptoms uncommon in children • Diagnosis primarily made by echocardiography • Cardiac MR can depict function, flow, & anatomy
(Left) Single frontal chest radiograph in a 4-year-old child demonstrates cardiomegaly & increased pulmonary vascularity. The patient had a large, untreated atrial septal defect (ASD). (Right) Four-chamber view from an SSFP (bright blood) cardiac MR shows a secundumtype defect of the atrial septum . Note the L → R flow across the ASD causing dephasing artifact in the right atrium (RA).
(Left) Four-chamber view from an SSFP (bright blood) cardiac MR shows a sinus venosus ASD with the defect in the superolateral aspect of the atrial septum ſt. This defect is nearly always associated with right upper lobe partial anomalous pulmonary venous return. (Right) Axial image from a coronary CTA shows a patent foramen ovale ſt with a typical oblique defect & flap in the atrial septum. This is seen in 25% of the population. Note that the size of the RA is normal as L → R shunting does not occur.
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Atrial Septal Defect KEY FACTS
TERMINOLOGY
CLINICAL ISSUES
• ASD: Defect(s) in cardiac atrial septum; may be isolated anomaly or associated with other congenital heart lesions • L → R shunt: Blood from left heart bypasses systemic circulation to enter right heart ○ Most ASD sequelae related to long-term L → R shunting • Types of ASD ○ L → R shunts: Ostium secundum (70-90%), ostium primum, sinus venosus, unroofed coronary sinus defects ○ Patent foramen ovale only allows R → L shunting, usually transient given normal atrial pressures – Increased stroke risk; unclear migraine association
• ASD: 10% of congenital heart disease (CHD) in children, yet 30% of CHD in adults • Secundum ASD: Majority of patients asymptomatic; detected due to murmur or other medical work-up ○ Spontaneous closure occurs in many children ○ Rarely presents in childhood with failure to thrive, respiratory infection, tachypnea ○ Subtle symptoms more likely in 2nd decade, though large defects frequently do not present until adulthood – Fatigue, exercise intolerance, syncope, shortness of breath, palpitations – ASD leading to severe pulmonary hypertension: Median age of detection is 51 years ○ Repair indicated if shunt ratio > 1.5:1 or defect > 10 mm – Percutaneous closure with occlusion device • Primum/atrioventricular septal defect more severe; requires early surgical repair • Sinus venosus ASDs require surgery for complex anatomy
IMAGING • L → R shunting leads to chronic volume overload of right heart, eventual enlargement of RA, RV, & PA ○ Secondary findings & symptoms uncommon in children • Diagnosis primarily made by echocardiography • Cardiac MR can depict function, flow, & anatomy
(Left) Single frontal chest radiograph in a 4-year-old child demonstrates cardiomegaly & increased pulmonary vascularity. The patient had a large, untreated atrial septal defect (ASD). (Right) Four-chamber view from an SSFP (bright blood) cardiac MR shows a secundumtype defect of the atrial septum . Note the L → R flow across the ASD causing dephasing artifact in the right atrium (RA).
(Left) Four-chamber view from an SSFP (bright blood) cardiac MR shows a sinus venosus ASD with the defect in the superolateral aspect of the atrial septum ſt. This defect is nearly always associated with right upper lobe partial anomalous pulmonary venous return. (Right) Axial image from a coronary CTA shows a patent foramen ovale ſt with a typical oblique defect & flap in the atrial septum. This is seen in 25% of the population. Note that the size of the RA is normal as L → R shunting does not occur.
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