DORV and Other Malposition Anomalies

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1. Definition

Double outlet right ventricle

Both great arteries arise wholly or in large part from right ventricle

Ventricular septal defect - one great artery may overlie VSD (50% rule)

Classification controversy

Tetralogy of Fallot

Taussig-Bing heart

2. Ventricular Septal Defect

Usually large

Subaortic (simple DORV)

Subpulmonary (Taussig-Bing heart)

Doubly committed

Non committed

DORV
VSD

3. Other Anatomic Features

Infundibulum

Double conus in 3/4 with sub-Aortic VSD

Double or single conus equal with subPA VSD

Great arteries

Usual position in most

Side-by-side less common

D or L TGA rare

Pulmonary stenosis

Common with sub-Aortic VSD (infundibular)

Uncommon with subPA VSD

Coronary artery pattern follows great vessels

Conus
Double Conus

4. Clinical Features

Presentation: large VSD, high pulmonary flow, not cyanotic, but decreased SaO2

Streaming brings high SaO2 blood to Ao (subAo VSD) or high flow to PA(subPA VSD)

Cyanosis related to PS or rapid onset PVD (subPA VSD)

Natural history similar to large VSD or TET

5. Operations

DORV with subaortic VSD

Intraventricular tunnel VSD to Ao

Low risk

Age 6 months

Extracardiac conduit RV to PA for PS

DORV with subpulmonary VSD (Taussig-Bing Heart)

Close VSD to PA plus arterial switch procedure

Complex intraventricular tunnel VSD to Ao with infundibular resection

Atrial switch no longer used

DORV with non-committed VSD

Fontan procedure

Complex intraventricular tunnel to Ao or PA

Patch
Repair

6. Atrial Isomerism

Definition

Atrial isomerism means both atria are similar - bilateral right or bilateral left

A subset of situs ambiguous - asymmetric structures tend to be symmetric

Viscera heterotaxy

Asplenia syndrome: bilateral atrial, thoracic and abdominal RIGHT sidedness

Polysplenia syndrome: bilateral atrial, thoracic and abdominal LEFT sidedness

Thoracic situs best indicated by bronchial anatomy

7. Morphology

Conduction System

Right (asplenia) - bilateral SA and AV nodes, NSR

Left (polysplenia) - SA node hypoplastic, CHB 10%

Systemic venous return

Right - commonly anomalous

Left - 20% anomalous

Pulmonary venous return

Right - TAPVC 20%

Left - Cor Triatriatum common, TAPVC rare

8.Atrioventricular connection ambiguous, 25% univentricular

Great arteries - DORV or TGA 50-85%

Common atrium - AV canal defect 50-95%

VSD nearly always present

Pulmonary stenosis or atresia

Right - common

Left - uncommon

9. Treatment

Natural history

Right - asplenia associated pneumococcal infections

Left - complete heart block, biliary atresia

Operations

Complex atrial baffle (venous anomaly + AV canal) Fontan (pulmonary atresia)

Palliative shunts and PA banding

10. Positional Anomalies of Conotruncus