Tetralogy of Fallot
Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect, combining a ventricular septal defect (VSD) with obstruction between the right ventricle and pulmonary artery. Together, these allow unoxygenated blood to bypass the lungs and enter circulation, causing the characteristic bluish discoloration known as cyanosis.
Surgery is typically performed in early childhood. The repair closes the VSD and relieves the right ventricular outflow obstruction, eliminating cyanosis and improving exercise capacity. While outcomes are excellent, opening the pulmonary valve to relieve obstruction leaves behind a degree of pulmonary regurgitation (valve leak) — the central challenge that persists into adulthood.
Most adults with a repaired TOF live full, active lives. That said, lifelong follow-up with an adult congenital heart disease (ACHD) specialist is essential. Key concerns include arrhythmias, right ventricular function, and pulmonary valve or artery abnormalities. Pregnancy is generally well tolerated after a successful repair.
Assessment of Repair
Regular surveillance is important to detect and address residual abnormalities before they progress. For most adults with repaired TOF, the central concern is the pulmonary valve and the right ventricle.
After childhood repair, most patients develop pulmonary insufficiency - a leak in the pulmonary valve that is well tolerated for years but can silently enlarge the right ventricle over time. Once the ventricle becomes significantly dilated, pulmonary valve replacement is recommended to prevent irreversible damage and reduce the risk of arrhythmia and heart failure.
The decision to replace the pulmonary valve is based on right ventricle size and function, exercise capacity, and heart rhythm status. Cardiac MRI is the preferred tool for this assessment, offering superior measurement of ventricular volumes, the degree of pulmonary regurgitation, and detailed imaging of the pulmonary arteries - including detection of narrowing that may warrant stenting. There are now published guideliness regarding timing of pulmonary valve replacement. It is hoped that this will result in more timely referral for pulmonary valve replacement before the right ventricle becomes too large.
When pulmonary valve replacement is needed, a bioprosthetic valve is used - avoiding lifelong anticoagulation and preserving the option for a future catheter-based valve-in-valve procedure. The Schneeweiss Adult Congenital Heart Center has been at the forefront of this approach since 2007, when our interventional cardiologists performed one of the first Melody percutaneous pulmonary valve replacements in the United States. Since then, we have built one of the country’s most experienced programs in catheter-based pulmonary valve replacement, and our team continues to lead the adoption of new transcatheter technologies as they emerge. For patients with suitable anatomy, this minimally invasive approach offers a compelling alternative to heart surgery. Surgery may be recommended if there are other heart abnormalities that require correction at the same time, such as tricuspid regurgitation. Pulmonary valve replacement - surgical or catheter-based - typically results in roughly a 30% reduction in right ventricular size.
Less commonly, adults may require intervention for significant narrowing within the right ventricle or a residual VSD. On occasion, aortic valve replacement or aortic root surgery may be needed for a leaking aortic valve or marked aortic enlargement.
Arrhythmias
Both atrial and ventricular arrhythmias occur in adults with TOF. Atrial flutter is most common, though atrial fibrillation and other rhythm disturbances also arise, causing palpitations, fatigue, dizziness, and fluid retention. Restoring a normal rhythm is generally recommended through cardioversion, medication, or catheter ablation.
Ventricular arrhythmias originate in the lower chambers and range from brief, benign episodes to sustained rhythms that can be life-threatening. Treatment may include medications, radiofrequency ablation, or an implantable cardioverter-defibrillator (ICD). All patients with ventricular arrhythmias should be evaluated by a specialist with expertise in both congenital heart disease and electrophysiology.
On rare occasions, a patient reaches adulthood with an unrepaired TOF. A thorough evaluation by our team will determine whether corrective surgery remains a viable and beneficial option.