In a multicenter cohort, inducible sustained VT in patients with TOF was an independent risk factor for subsequent clinical VT or SCDS10.8-19 ; patients in that early study had cardiomegaly and prior palliative shunts. Patients with repaired Figure 16. Prevention of SCD in patients with adult congenital heart disease. Colors correspond to Class of Recommendation in Table 1. See Section 10.8 for discussion. *High-risk features: prior palliative systemic to pulmonary shunts, unexplained syncope, frequent PVC, atrial tachycardia, QRS duration 180 ms, decreased LVEF or diastolic dysfunction, dilated right ventricle, severe pulmonary regurgitation or stenosis, or elevated levels of BNP. Frequent VA refers to frequent PVCs and/or nonsustained VT. ACHD indicates adult congenital heart disease; BNP, B-type natriuretic peptide; EP, electrophysiological; ICD, implantable cardioverter-defibrillator; LVEF, left ventricular ejection fraction; PVC, premature ventricu- lar complexes; SCD, sudden cardiac death; TOF, tetralogy of Fallot; VA, ventricular arrhythmia; and VT, ventricular tachycardia. CLINICAL STATEMENTS AND GUIDELINES TOF account for approximately 50% of ICD implantations in adult congenital heart Appropriate ICD shocks occur in up to 7.7% per year of patients with TOF receiving the ICD for primary prevention, compared with 9.8% per year in patients with a secondary pre- In another study including patients with TOF as well as other lesions, inducible sustained VT did not correlate with subsequent appropriate Because of the high incidence of inappropriate shocks in 20% to 30% and compli- cations in at least 30% of patients with adult con- genital heart disease,S10.8-14 S10.8-17,S10.8-39,S10.8-40,S10.8-43 in addition to financial and psychological burdens, shared decision-making regarding primary preven- tion ICDs is essential. 7. In patients with recurrent sustained monomorphic VT, catheter ablation of VT can be effective.S10.8-21 S10.8-25 Hemodynamic repair, at the time that an arrhythmia is being ablated surgically, should be considered. 