What is Right Sided Obstructive Ventricular (RSOV) disease in congenital heart defects?

Right-Sided Obstructive Ventricular Disease in Congenital Heart Defects

Right-Sided Obstructive Ventricular (RSOV) disease refers to a spectrum of congenital heart defects involving obstruction to the right ventricular outflow tract (RVOT) that can occur at multiple levels: valvular, subvalvular, or supravalvular. 1

Anatomical Classification

RSOV can be categorized based on the level of obstruction:

1. Valvular obstruction:

   • Pulmonary valve stenosis (most common form, accounting for 80-90% of RVOT obstructions)
   • Dysplastic pulmonary valve (seen in approximately 20% of valvular PS cases)

2. Subvalvular obstruction:

   • Infundibular stenosis (a key component of Tetralogy of Fallot)
   • Subinfundibular stenosis (double-chambered right ventricle)
   • Reactive myocardial hypertrophy secondary to pulmonary valvular stenosis

3. Supravalvular obstruction:

   • Pulmonary artery stenosis

Associated Lesions

RSOV frequently coexists with other congenital heart defects:

• Ventricular septal defects (VSDs)
• Tetralogy of Fallot (which includes RVOT obstruction as a defining feature)
• Pulmonary artery aneurysms
• Atrial septal defects
• Other complex congenital heart defects

Clinical Manifestations

Symptoms depend on the severity of obstruction and associated lesions:

• Dyspnea on exertion
• Fatigue
• Chest pain (angina-like symptoms)
• Dizziness or syncope
• Right-sided heart failure (in advanced cases)
• Cyanosis (if there is right-to-left shunting through an associated defect)

Diagnostic Evaluation

1. Physical examination:

   • Harsh systolic murmur that increases with inspiration
   • Right ventricular heave
   • Palpable thrill
   • Widely split S2 with diminished pulmonary component

2. Electrocardiogram:

   • Right ventricular hypertrophy
   • Right axis deviation
   • Upright T waves in right-sided leads (in 40% of patients with double-chambered RV) 1

3. Imaging:

   • Echocardiography: First-line diagnostic tool to identify the level and severity of obstruction, associated lesions, and right ventricular function
   • Cardiac MRI: Provides detailed anatomical information and accurate assessment of right ventricular function
   • Cardiac catheterization: Confirms diagnosis and provides hemodynamic information when needed

Management

Management depends on the type and severity of obstruction:

1. Medical management:

   • Beta-blockers may be beneficial in adults with severe complexity congenital heart disease and frequent or complex ventricular arrhythmias 1
   • Avoid class Ic antiarrhythmic medications and amiodarone in asymptomatic ventricular arrhythmias as they may be harmful 1

2. Interventional procedures:

   • Balloon valvuloplasty for valvular pulmonary stenosis
   • Stenting for selected cases of supravalvular stenosis

3. Surgical management:

   • Surgical resection for significant subvalvular or infundibular obstruction with peak gradient >50 mmHg or mean gradient >30 mmHg in symptomatic patients 1
   • Pulmonary valve replacement for severe pulmonary regurgitation after previous repair
   • Complete repair of associated defects (e.g., VSD closure in Tetralogy of Fallot)

Long-term Complications

1. Right ventricular dysfunction: Progressive RV dysfunction may develop due to chronic pressure or volume overload 1, 2

2. Arrhythmias: Ventricular arrhythmias are common, particularly in patients with repaired Tetralogy of Fallot 1

3. Heart failure: Right-sided heart failure can develop, especially in patients with longstanding obstruction 1

4. Sudden cardiac death: Risk is higher in patients with repaired Tetralogy of Fallot and other severe forms of RSOV 1

Follow-up Recommendations

• Regular follow-up with a cardiologist specialized in adult congenital heart disease
• Periodic echocardiography to monitor RV function and obstruction severity
• Exercise testing to assess functional capacity
• Cardiac MRI for comprehensive assessment of RV function
• Electrophysiological studies may be useful in high-risk patients to evaluate risk of sustained ventricular tachycardia/ventricular fibrillation 1

Important Considerations

• Early intervention before the development of RV dysfunction is crucial for better outcomes
• Patients with RSOV should be followed at specialized adult congenital heart disease centers 3
• The right ventricle has remarkable ability to adapt to pressure and volume load, but late referral for intervention is common and may result in irreversible RV dysfunction 3
• Multiple levels of obstruction can coexist and should be thoroughly evaluated 1

RSOV represents an important subset of congenital heart defects that requires careful monitoring and timely intervention to prevent long-term complications related to right ventricular dysfunction.