Many<unk> s go undiagnosed in childhood
From superior to inferior,<unk> s occur in:
Sinus venosus (5%)
Ostium secundum (75%), ostium primum (15-20%)
Very rarely coronary sinus<unk> 
Spontaneous closure in up to 40% of patients within the first 5 years of life
By 40s, patients may develop symptoms
Small<unk> s < 5 mm in diameter may not generate symptoms
5-10 mm defects lead to symptoms in 4th and 5th decade of life
> 10 mm defects present with symptoms in 3rd decade
LV stiffness increases as a part of normal aging, impairing left heart diastolic filling
Increases left to right shunt across<unk> 
Produces RA and RV volume overload
May predispose to paradoxical embolus, causing stroke, TIA, acute limb ischemia, mesenteric ischemia, etc.
Right to left shunt may occur during coughing, for example
Pulmonary hypertension produces this shunting pattern even at rest
Unlike ventricular<unk>  defects, uncomplicated<unk> s are not associated with high risk of bacterial endocarditis (lower turbulence and velocity of blood flow)
Sinus venosus (5%)
Ostium secundum (75%), ostium primum (15-20%)
Very rarely coronary sinus<unk> 
Small<unk> s < 5 mm in diameter may not generate symptoms
5-10 mm defects lead to symptoms in 4th and 5th decade of life
> 10 mm defects present with symptoms in 3rd decade
Increases left to right shunt across<unk> 
Produces RA and RV volume overload
Right to left shunt may occur during coughing, for example
Pulmonary hypertension produces this shunting pattern even at rest
Atrial septal defect
Cyanotic
Ventricular septal defect
Tetralogy of fallot
Tricuspid atresia
Total anomalous pulmonary venous return
Patent ductus arteriosus
Transposition of the great arteries