*See Tables 3 and 4 for details on the ACHD AP classification system. 3D indicates 3-dimensional; ACHD, adult congenital heart disease; AP, anatomic and physiological; ASD, atrial septal defect; CCT, cardiac computed tomography; CHD, congenital heart disease; CMR, cardiovascular magnetic resonance; IE, infective endocarditis; PAH, pulmonary arterial hypertension; PR, pulmonary regurgitation; Qp:Qs, pulmonary systemic blood flow ratio; RV, right ventricle; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; and VSD, ventricular septal defect. Table 6. Continued Circumstance Possible Solution Rationale Example Table 7. Use of ECGs in ACHD Evaluation Identification of sinus bradycardia or junctional rhythm in patients at risk of sinus node dysfunction (especially after the Mustard, Senning, Glenn, or Fontan procedure) Identification of clinically inapparent intra-atrial re-entry tachycardia in patients who have had atriotomy Identification of atrioventricular block in patients at risk for progression of atrioventricular conduction system disease (especially CCTGA) Evaluation of rhythm in patients with pacemakers Measurement of QRS duration in patients after repair of TOF and as part of CRT evaluation Preoperatively to compare with postoperative ECGs in patients undergoing heart surgery and noncardiac surgery Postoperatively to identify arrhythmias (eg, atrial ectopic tachycardia, atrial flutter, AF, junctional ectopic tachycardia, atrioventricular block) Diagnosis of Wolff-Parkinson-White Syndrome in patients with Ebstein anomaly Initial evaluation of suspected acute coronary syndromes ACHD indicates adult congenital heart disease; AF, atrial fibrillation; CCTGA, congenitally corrected transposition of the great arteries; CRT, cardiac resynchronization therapy; ECG, electrocardiogram; and TOF, tetralogy of Fallot. Table 8. 