Overview of management and follow-up for infants and children with isolated secundum atrial septal defects

ASD: atrial septal defect; ECG: electrocardiogram; MRI: magnetic resonance imaging; PFO: patent foramen ovale; Qp/Qs: ratio of pulmonary to systemic blood flow.

* The echocardiogram report will characterize the size of the defect, typically with one of the following descriptors: "PFO," "trivial ASD," "small ASD," "moderate ASD," or "large ASD." PFOs, trivial ASDs, and small ASDs constitute a spectrum. The distinction between these categories is generally based on the size of the defect and whether there is a visible tissue flap. Small defects with a tissue flap are usually defined as PFO whereas those without a tissue flap are defined as secundum ASD. Trivial ASDs are usually <3 mm in diameter. However, when characterizing the size of the defect, the diameter should be interpreted in the context of the patient's size. Refer to UpToDate topics on ASDs for additional details.

¶ If the infant is clinically well at the one-year visit, the echocardiogram can be deferred until the next visit.

Δ ASD closure is generally deferred until after age two years in asymptomatic patients because there is a possibility, albeit small, of spontaneous closure during the first two years of life. Rarely, children with large ASDs may develop symptomatic heart failure in infancy or early childhood. If this occurs, the child should be referred for early surgical closure.

◊ The usual clinical standard for ASD closure is Qp/Qs >2:1, though high-quality evidence supporting this threshold is generally lacking. Some experts use lower thresholds (eg, >1.7:1 or >1.5:1). Cardiac catheterization is considered the gold standard for measuring Qp/Qs, but noninvasive techniques (eg, pulsed Doppler echocardiography or phase contrast MRI) are accepted alternatives in experienced centers. If quantitative measures of Qp/Qs are not available, echocardiographic evidence of substantial right heart enlargement and qualitative color and spectral Doppler findings of a large amount of left-to-right shunting through the ASD can be sufficient to justify ASD closure.

• Diameter of the ASD is >30 mm
• The rim of tissue around the defect is not sufficient to allow effective closure without obstruction or impingement on adjacent cardiac structures (ie, <5 mm)
• The defect is not a secundum ASD (ie, sinus venosus defect, coronary sinus defect, or primum ASD)