Core entities

• Transposition of the Great Arteries (TGA)
• Double Outlet Right Ventricle (DORV)
• Tetralogy of Fallot (TOF)
• Congenitally Corrected Transposition of the Great Arteries

Feature	Tetralogy of Fallot	Double Outlet Right Ventricle	Transposition of the Great Arteries
Great arteries	Crossing	Crossing or abnormal	Parallel
LV direct outlet	Yes (partly)	No	Yes (to PA)
Aortic override	30–50% typical	>50% (often >70%)	None
VSD	Large malalignment	Always present	Variable
Pulmonary artery	Small	Variable	Normal
3-vessel view	Small PA	Variable	Aorta anterior
LVOT continuity	Present	Absent	Present
RVOT obstruction	Typical	Variable	None

Feature	TGA	DORV	TOF	CCTGA
Great arteries	Parallel	Both from RV	Crossing	Parallel
LV connection	To PA	Often to VSD	To overriding aorta	To pulmonary artery
RV connection	To Aorta	To both vessels	To overriding aorta	To aorta
VSD	Required for survival	Always present	Always present	Variable
AV connections	Normal	Normal	Normal	Discordant

A. Transposition of the Great Arteries (TGA)

Parallel great arteries

Outflow tract:

• Aorta arises from right ventricle
• Pulmonary artery arises from left ventricle
• No normal crossing

B. Double Outlet Right Ventricle (DORV)

Both great arteries arise predominantly from RV

VSD is mandatory.

LV has no direct outlet.

Instead: LV empties via VSD

Great arteries:

• crossing present
• abnormal alignment

C. Tetralogy of Fallot (TOF)

Classic tetrad:

• VSD
• Overriding aorta
• RV hypertrophy
• Pulmonary stenosis

Overriding aorta - Aorta sits: over VSD

Receiving blood from both ventricles.

Pulmonary artery: small

3-vessel view: Small pulmonary artery

D. Congenitally Corrected TGA (CCTGA)

Double discordance

• AV discordance
• VA discordance

Result: Circulation becomes "physiologically corrected."

Ventricular inversion

Right ventricle appears: on the left side

With:

• moderator band
• coarse trabeculation

Ventricular inversion

Great arteries:

Usually: parallel; Like TGA.

But: AV connections abnormal.