Many adult CCTGA patients are referred for tri- cuspid valve replacement late, when symptomatic and already suffering from moderate-to-severe CLINICAL STATEMENTS AND GUIDELINES TR and ventricular dysfunction.S4.4.1.4-16 In CCTGA patients referred for TVR, 10-year postopera- tive survival is <20% when the preoperative sys- temic ventricular ejection fraction is <40%S4.4.1.4-9 In a retrospective review of 46 CCTGA patients referred for TR surgery, preoper- ative systemic ventricular ejection fraction was the only independent predictor of postoperative sys- temic ventricular ejection fraction at 1 year.S4.4.1.4-3 4. Adults with CCTGA and pulmonary atresia or ste- nosis were often managed in childhood by plac- ing a conduit from the morphologic LV to the PA, and progressive conduit dysfunction is common. Conduit intervention or replacement will diminish the pressure in the subpulmonic ventricle and may result in ventricular septal shift toward the subpulmonic left ventricle, including the septal leaflet of the systemic tricuspid valve and thus can result in worsening of TR and a detrimental impact on systemic RV function.S4.4.1.4-5 4.4.2. Fontan Palliation of Single Ventricle Physiology (Including Tricuspid Atresia and Double Inlet Left Ventricle) Recommendations for Fontan Palliation of Single Ventricle Physiology Referenced studies that support recommendations are summarized in Online Data Supplement 48. COR LOE Recommendations Diagnostic I C-LD New presentation of an atrial tachyarrhythmia in adults with Fontan palliation should be managed promptly and include prevention of thromboembolic events and consultation with an electrophysiologist with CHD Diagnostic (Continued) I C-EO Adults after Fontan palliation should be evaluated annually with either echocardiography or CMR. I C-EO Cardiac catheterization should be performed in adults before initial Fontan surgery or revision of a prior Fontan connection to assess suitability of preintervention hemodynamics for Fontan physiology or revision of a prior Fontan connection. 