Atrial septal defect


  • Many ASDs go undiagnosed in childhood
  • From superior to inferior, ASDs occur in[1]:
    • Sinus venosus (5%)
    • Ostium secundum (75%), ostium primum (15-20%)
    • Very rarely coronary sinus ASD
  • Spontaneous closure in up to 40% of patients within the first 5 years of life
  • By 40s, patients may develop symptoms[2]
    • Small ASDs < 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[3][4]
    • Increases left to right shunt across ASD
    • Produces RA and RV volume overload
  • May predispose to paradoxical embolus, causing stroke, TIA, acute limb ischemia, mesenteric ischemia, etc.[5]
    • Right to left shunt may occur during coughing, for example
    • Pulmonary hypertension produces this shunting pattern even at rest
  • Unlike ventricular septal defects, uncomplicated ASDs are not associated with high risk of bacterial endocarditis (lower turbulence and velocity of blood flow)

Clinical Features

A patient may be asymptomatic or have any of the following features:

Differential Diagnosis

Congenital Heart Disease Types


ECG Findings

Crochetage pattern on ECG for atrial septal defect


Positive Bubble Test in a pediatric patient demonstrating a Atrial Septal Defect [10]
  • Subcostal view preferred window, due to interatrial septum perpendicular to echo signal (apical four-chamber is parallel to ASD echo signal)
  • Clues to ASD
    • Hypermobile interatrial septum
    • Abrupt septal irregularity
    • RA and/or RV volume overload
    • Pulmonary artery dilation
    • High pulmonary artery pressures
  • TTE with Doppler can demonstrate most shunting
  • Agitated saline with Valsalva maneuver to increase right to left shunting is more diagnostic[11]


  • Medical management of complications (Afib, pulmonary HTN, etc.)
  • Avoid pregnancy and exertional activity in ASD complicated by pulmonary hypertension
  • Indications for ASD closure
    • Right heart overload with RA or RV enlargement
    • Complicated ASDs


  • If no acute complications → discharge with outpatient follow-up

See Also

External Links


  1. Warnes CA, Williams RG, Bashore TM, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease. J Am Coll Cardiol. 2008;52:e143–263.
  2. Craig RJ, Selzer A. Natural history and prognosis of atrial septal defect. Circulation. 1968;37:805–15.
  3. Fleg JL, Shapiro EP, O’Connor F, Taube J, Goldberg AP, Lakatta EG. Left ventricular diastolic filling performance in older male athletes. JAMA. 1995;273:1371–5.
  4. Swinne CJ, Shapiro EP, Lima SD, Fleg JL. Age-associated changes in left ventricular diastolic performance during isometric exercise in normal subjects. Am J Cardiol. 1992;69:823–6.
  5. Ward R, Jones D, Haponik EF. Paradoxical embolism. An underrecognized problem. Chest. 1995;108:549–58.
  6. Gabriels C, De Meester P, Pasquet A, et al. A different view on predictors of pulmonary hypertension in secundum atrial septal defect. Int J Cardiol. 2014;176:833–40.
  7. Knipe K et al. Cyanotic congenital heart diseases. Radiopaedia.
  8. Heller, J et al. “Crochetage” (Notch) on R wave in inferior limb leads: A new independent electrocardiographic sign of atrial septal defect. J Am Coll Cardiol. 1996;27(4):877-882 full text]
  9. Gatzoulis MA, Freeman MA, Siu SC, Webb GD, Harris L. N Engl J Med. 1999 Mar 18; 340(11):839-46.
  11. Shub C, Dimopoulos IN, Seward JB, et al. Sensitivity of two-dimensional echocardiography in the direct visualization of atrial septal defect utilizing the subcostal approach: experience with 154 patients. J Am Coll Cardiol. 1983;2:127–35.
  12. Martin SS et al. Atrial Septal Defects – Clinical Manifestations, Echo Assessment, and Intervention. Clin Med Insights Cardiol. 2014; 8(Suppl 1): 93–98.