However, a diagnostic catheterization may be necessary to determine detailed hemodynamics for decision-making or to clarify discrepant or inconclusive noninvasive imaging data. Patients with reduced functional capacity presumed caused by hemodynamically important secun- dum ASD (moderate or large left-to-right shunt and evidence of right heart volume overload in the absence of significant PAH) benefit from sur- gical or transcatheter closure of the secundum Patients who do not undergo ASD closure have worse long-term outcomes, including more atrial arrhythmias, reduced func- tional capacity, and eventually greater degrees of PAH. Older adults should be evaluated for left atrial hypertension resulting from diastolic dysfunction, which may cause similar symptoms but could result in clinical worsening after ASD closure because of further increase in left atrial pressures when blood from the relatively restric- tive and higher pressure left atrium can no longer decompress into the lower pressure right atrium. Cyanosis with exercise typically occurs in associ- ation with poor RV diastolic compliance and he- modynamics with exercise, and the ASD acts as a pop-off to maintain cardiac output. However, exercise-induced cyanosis is not an absolute con- traindication to ASD closure, because there are rare cases of either streaming or directed tricuspid regurgitation (TR) leading to right-to-left shunting with exercise not related to abnormal RV diastolic pressures that may allow for closure after expert evaluation. Data are most compelling that closure CLINICAL STATEMENTS AND GUIDELINES improves functional status, although some de- scriptive studies support improved long-term out- comes after closure as well.S4.1.1-7 S4.1.1-12 5. Available percutaneously deployed ASD closure devices are approved for closure of secundum- type defects. 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. 