Primum, sinus venosus, and coronary sinus ASDs should be closed surgically because of the absence of appropriate rims for percuta- neous device placement and the proximity of the atrioventricular valves and conduction system to the closure device. Congenital heart surgeons are trained in the nuances of repair of such defects, including common association with anomalous pulmonary venous connection and abnormalities of the atrioventricular valves.S4.1.1-24,S4.1.1-25 6. Patients who do not undergo ASD closure have worse long-term outcomes, including more atrial arrhythmias, reduced functional capacity, and eventually greater degrees of PAH.S4.1.1-7 S4.1.1-10, However, concomitant diseases may in- fluence the anticipated benefit of ASD closure in ameliorating symptoms and improving func- tional capacity, and it has not been clearly dem- onstrated that ASD closure in asymptomatic adults prevents long-term complications. Data suggest that ASD closure improves functional Table 13. ASD: Routine Follow-Up and Testing Intervals Frequency of Routine Follow-Up and Testing Physiological Stage A* (mo) Physiological Stage B* (mo) Physiological Stage C* (mo) Physiological Stage D* (mo) Pulse oximetry As needed As needed Each visit Each visit Exercise test As needed As needed 12 24 6 12 *See Tables 3 and 4 for details on the ACHD AP classification system. 6-minute walk test or CPET, depending on the clinical indication. ACHD indicates adult congenital heart disease; CPET, cardiopulmonary exercise test; ECG, electrocardiogram; and TTE, transthoracic echocardiogram. Figure 1. Secundum ASD. *Combination therapy with bosentan and PDE-5 inhibitor if symptomatic improvement does not occur with either alone. ACHD indicates adult congenital heart disease; ASD, atrial septal defect; PAH, pulmonary artery hypertension; PASP, pulmonary artery systolic pressure; PDE-5, phosphodiesterase type-5 inhibitors; PH, pulmonary hypertension; and Qp:Qs, pulmonary systemic blood flow ratio. 