Management of Tetralogy of Fallot

Surgical Repair Strategy

The American College of Cardiology recommends complete surgical repair of Tetralogy of Fallot, ideally performed within the first year of life, addressing all four anatomic components: VSD closure, RVOT obstruction relief, pulmonary valve management, and extracardiac conduit placement when necessary 1
Complete repair includes VSD closure and relief of RVOT obstruction through infundibular muscle resection, pulmonary valvotomy, and transannular patch when the pulmonary annulus is inadequate 2, 3

The American Heart Association recommends mandatory annual follow-up with an adult congenital heart disease (ACHD) specialist for life, as pulmonary regurgitation, RV dysfunction, and arrhythmias determine long-term morbidity and mortality 1
Clinical assessment by ACHD cardiologist with focused history on exercise tolerance, palpitations, dizziness, or syncope is necessary 4, 1
12-lead ECG to monitor QRS duration—QRS ≥180 ms identifies high risk for sustained ventricular tachycardia and sudden cardiac death 2, 5
Comprehensive transthoracic echocardiography assessing RV size/function, pulmonary regurgitation severity, residual RVOT obstruction, tricuspid regurgitation, and aortic root dilation is recommended 1, 5
Cardiac MRI for precise RV volume quantification and pulmonary regurgitation assessment, as echocardiography underestimates RV dysfunction 6, 1, 5
Periodic Holter monitoring with frequency individualized based on hemodynamics and clinical suspicion to detect ventricular arrhythmias 4, 1
Exercise testing to objectively assess functional capacity and detect exertional arrhythmias 7, 5

The incidence of sudden death in adult TOF patients is approximately 2.5% per decade, with ventricular tachycardia as the primary mechanism 4
Worrisome symptoms (palpitations, dizziness, syncope) mandate immediate evaluation with hemodynamic catheterization and electrophysiology study 4, 6
Documented sustained ventricular tachycardia or cardiac arrest requires implantable cardioverter defibrillator (ICD) placement 6, 7
Asymptomatic patients with nonsustained VT on surveillance monitoring should undergo electrophysiology study to refine arrhythmia risk, with consideration for surgery if significant pulmonary regurgitation exists 6
Inducible VT/VF or spontaneous sustained VT warrants ICD implantation if meaningful survival >1 year is expected 7
Recurrent sustained monomorphic VT or recurrent ICD shocks can be effectively treated with catheter ablation, though ICD remains necessary due to uncertain recurrence risk after ablation 6, 7
Beta blockers should be used in patients with frequent or complex ventricular arrhythmias to reduce sudden cardiac arrest risk 7

Pulmonary valve replacement (PVR) is the most common reintervention, required in 40-85% of patients 5-10 years after initial repair due to chronic pulmonary regurgitation causing progressive RV dilation and dysfunction 3
Symptomatic patients with severe pulmonary regurgitation require intervention 1
Asymptomatic patients with severe pulmonary stenosis or pulmonary regurgitation PLUS progressive or severe RV enlargement or dysfunction require intervention 1
Residual RVOT obstruction with RV/LV pressure ratio >0.7 or RV systolic pressure >50 mmHg requires intervention 1, 5
Hemodynamic abnormalities identified during evaluation for arrhythmias, such as residual VSD or significant valve regurgitation, may benefit from surgical intervention combined with intraoperative VT mapping and ablation 6, 7

Comprehensive echocardiography must assess RV size/function, pulmonary regurgitation severity, residual RVOT obstruction, tricuspid regurgitation, and aortic root dilation 5
Review cardiac MRI for RV volume, systolic function, and pulmonary regurgitation severity 5
Analyze ECG for QRS duration >180 ms, which mandates enhanced monitoring due to significantly increased arrhythmia risk 5
Coronary anatomy must be defined before any RVOT intervention to avoid interrupting important coronary vessels 4, 3
Maintain RV function by optimizing preload, reducing afterload, and supporting contractility 1, 5
Minimize increases in pulmonary vascular resistance by avoiding hypoxia, hypercarbia, acidosis, hypothermia, and excessive positive pressure ventilation 5
Prevent tachycardia which reduces diastolic filling time and coronary perfusion 5
Maintain systemic vascular resistance to prevent right-to-left shunting if residual ASD/VSD present 5
Defibrillator must be immediately available with antiarrhythmic medications prepared 1, 5

Underestimating RV dysfunction even in asymptomatic patients can lead to decompensation under anesthesia 5
Inadequate preoperative assessment without recent echocardiography and knowledge of residual lesions significantly increases risk 5
Excessive positive pressure ventilation increases RV afterload and impairs venous return 5
Ignoring QRS duration >180 ms substantially increases arrhythmia risk and should prompt enhanced monitoring 5
Delaying PVR until irreversible RV remodeling occurs worsens outcomes—intervention should occur before this threshold 3

Pregnancy is contraindicated in patients with unrepaired TOF 6
After repair, pregnancy is usually well tolerated if no important hemodynamic residua exist, functional capacity is good, and RV function is no more than mildly depressed with maintained sinus rhythm 6
Fetal risk: 4-6% risk of congenital heart disease in offspring; screening for 22q11.2 microdeletion should be performed before pregnancy for appropriate genetic counseling 6
Fetal echocardiography should be offered in the second trimester 6