Double-Outlet Right Ventricle

• • A congenital heart lesion that decreases pulmonary arterial blood flow resulting in a right to left shunt

  • Cyanosis and decreased oxygen delivery causes compensatory polycythemia (Hct > 70%) and spontaneous thrombosis

  • Exercise, acidosis, pain worsens cyanosis and can cause hypoxic spells

  • Squatting increases systemic resistance, causing increased pulmonary flow and blood oxygenation

  • β-Blockers (decreases spasm), fluid intake, HCO3 administration, norepinephrine (increases systemic resistance) may help decrease hypoxia

  • Clubbing due to proliferation of capillaries and AV fistulas in extremities

  • Bronchial and mediastinal arteries enlarge

  • Ductus arteriosus maintains flow to lungs during fetal development

  • Alprostadil early can allow time for optimization before definitive treatment

  • Operative options to increase pulmonary flow:

  • -Fontan procedure: Superior vena cava and inferior vena cava rerouted to pulmonary artery

Double-Outlet Right Ventricle (DORV)

• • Both great arteries (50% of annulus of each valve) arise from right ventricle

  • Uncommon and extremely complex to manage

  • Location of ventricular septal defect (VSD) (always present) determines classification

  • -Subaortic

    -Subpulmonary

    -Noncomitted (proximal to valve annuli)

    -Double committed (adjacent to annuli and flow directed at both arteries)

  • 33% of subaortic has subpulmonary obstruction and vice versa

  • Great vessel and coronary artery anatomy can vary

  • Subaortic VSD, rightward, posterior arrangement more common

Single Ventricle (SV)

• • 1 ventricular chamber receiving blood from both tricuspid and mitral valves

  • Associated with

  • -Abnormal great vessel arrangements, 85%

    -Common AV valve, 30%

    -Stenosis or regurgitation of AV valve, 25%

    -Pulmonary stenosis or atresia, 50%

    -Aortic stenosis, 33%

    -Situs inversus, dextrocardia, and asplenia, 20%

  • Clinical findings and prognosis related to relative pulmonary and systemic blood flow

Epidemiology

DORV

• • Extremely rare

SV

• • 3-5% of congenital heart defects

  • 75% dominant left portion of ventricle

Symptoms and Signs

DORV

• • Symptoms depend on location of VSD and degree of outflow obstruction

SV

• • Variable based on amount of pulmonary and systemic blood flow

Imaging Findings

• • Echocardiography

  • Catheterization

• • Echocardiography and catheterization for diagnosis

• • Echocardiography and catheterization for diagnosis

DORV

• • Surgical treatment depends on anatomy

  • Creation of intraventricular baffle to direct LV flow to aorta, closing septal defect, avoiding subpulmonary obstruction

  • Arterial switch is option

SV

• • Initial: Shunt/pulmonary artery band, ventricular partitioning, then staged correction toward Fontan procedure

Prognosis

DORV

• • 10-year survival, 60-80%

  • 33% require reintervention for outflow tract reobstruction

SV

• • 1-year survival, 40-80%