Which of the following statements is correct concerning atrial septal defects (ASD)?
A. Primum ASDs are the most common type
B. ASDs are 2-3 times more common in males when compared to females
C. Sinous venous defects are associated with partially anomalous pulmonary venous return.
D. Bacterial prophylaxis is recommended if the ASD is over 2 cm
The answer is C.
Atrial septal defects (ASDs) account for about 1/3 of all congenital heart disease. ASDs are about 2-3 times more prevalent in females. They are classified by their location. They include primum and secundum (ostium) defects, inferior and superior sinus venosus defects and coronary sinus defects. Secundum ASDs are the most common (80%). Primum ASDs are associated with AV canals. Sinus venosus defects are associated with partial anomalous pulmonary venous return (PAPVR). The inferior defects may be associated with scimitar syndrome.
Prophylaxis against infective endocarditis is not recommended for patients with an ASD unless associated with a valvular abnormality (mitral valve prolapse or mitral valve cleft). ASDs may be associated with supraventricular dysrhythmias and pulmonary hypertension, even for modest sized defects. This usually occurs later in life (for pediatrics) in the second and third decades of life.
The physiologic and hemodynamic effects of ASDs are related to the direction and amount of shunting between the atria. The amount of shunt is related to the size of the defect and the relative compliance of each side of the heart. Large defects (>1-2 cm) may be associated with pulmonary overcirculation. ASDs are usually associated with a LEFT to RIGHT shunt due to the relative compliance of the RIGHT ventricle compared to the LEFT.