Double Outlet Right Ventricle (DORV)

Double Outlet Right Ventricle (DORV) is a rare congenital heart disease in which both great arteries, the aorta and the pulmonary artery, originate from the right ventricle. This anomaly disrupts normal hemodynamics, leading to impaired blood oxygenation. Clinical presentation varies depending on the position of the ventricular septal defect (VSD) and the presence of pulmonary stenosis.
DORV accounts for approximately 1-2% of congenital heart diseases. It is often associated with other anomalies, such as aortic coarctation, valvular defects, and aortic arch malformations.

Anatomy and Pathophysiology

In DORV, the left ventricle is partially excluded from the arterial circulation, while the right ventricle pumps blood into both the aorta and the pulmonary artery. Hemodynamics depend on:

• The position of the ventricular septal defect (VSD), which influences the direction of blood flow.
• The presence of pulmonary stenosis, which may obstruct pulmonary blood flow.
• The relationship between the left and right ventricles in supporting systemic and pulmonary circulation.

Depending on the anatomical configuration, DORV may resemble Tetralogy of Fallot (in cases with pulmonary stenosis) or Transposition of the Great Arteries (in cases with subpulmonary VSD).

Signs and Symptoms

Symptoms vary depending on the anatomical type of DORV:

• Newborns with pulmonary stenosis: early cyanosis and signs of hypoxemia.
• Newborns with increased pulmonary blood flow: signs of heart failure, tachypnea, and excessive sweating.
• Heart murmur: present in most patients, with variable intensity.

Diagnosis

DORV can be diagnosed prenatally through fetal echocardiography. After birth, diagnosis is based on:

• Echocardiography: confirms the origin of the great arteries and the position of the VSD.
• Electrocardiogram (ECG): may show right ventricular hypertrophy.
• Cardiac MRI: useful for pre-surgical assessment in complex cases.
• Cardiac catheterization: used in specific cases to assess pulmonary resistance.

Treatment

Surgery is the only definitive treatment and must be tailored to the defect's anatomy. The main surgical strategies include:

• Intraventricular tunnel repair: in cases with a favorable VSD location, a tunnel is created to direct left ventricular blood into the aorta.
• Rastelli procedure: indicated for patients with pulmonary stenosis, involving the implantation of a valved conduit between the right ventricle and the pulmonary artery.
• Arterial switch procedure: used in cases resembling Transposition of the Great Arteries, with reorientation of arterial connections.

In complex cases, a palliative approach may be required before definitive correction.

Prognosis

The prognosis depends on the anatomical configuration and the success of surgical correction. Without treatment, survival is limited. With proper surgical intervention, long-term quality of life is generally good. Major complications include valvular dysfunction, residual stenosis, and arrhythmias.

References
1. Rao P.S. et al. Double-Outlet Right Ventricle: A Comprehensive Appraisal. Am Heart J. 1988;116(1 Pt 1):123-137.
2. Yeh T. Jr. et al. Outcome After Biventricular Repair for Double-Outlet Right Ventricle. Ann Thorac Surg. 2007;84(2):591-598.
3. Huhta J.C. et al. Double Outlet Right Ventricle: Diagnosis and Management. Br Heart J. 1982;48(2):109-118.
4. Chen Q. et al. Long-Term Outcomes of Surgical Repair in DORV. J Thorac Cardiovasc Surg. 2019;158(5):1120-1132.
5. Van Praagh R. et al. Pathophysiology and Surgical Implications of Double-Outlet Right Ventricle. Pediatr Cardiol. 2018;39(3):805-815.
6. Bove E.L. et al. Evolution of Surgical Strategies in Double-Outlet Right Ventricle. J Am Coll Cardiol. 2020;75(8):950-963.