Single Ventricle

Question 1

What is Double inlet left ventricle (DILV)?

Answer 1

Hearts where both atrioventricular (AV) valves are aligned with and connected to one ventricular chamber of left ventricular morphology.

DILV may involve one AV valve straddling the ventricular septum by greater than 50%.

Question 2

What types of AV valves are often found in DILV?

Answer 2

Tricuspid or mitral valve.

One AV valve near the free wall can be of mitral valve morphology, while the one near the septal wall is more of tricuspid valve morphology.

Question 3

What percentage of DILV cases may exhibit hypoplasia and stenosis of one AV valve?

Answer 3

15–20%.

This refers to the underdevelopment and narrowing of one of the AV valves.

Question 4

In DILV, what anatomical feature is characteristic of the left ventricular chamber?

Answer 4

A free wall on one side with multiple papillary muscles and a smooth septal wall.

This morphology is typical for the left ventricle.

Question 5

What is the position of the incomplete right ventricle in DILV?

Answer 5

Always carried on its antero-superior shoulder.

This indicates the anatomical positioning of the right ventricle in relation to the left ventricle.

Question 6

What is left-handed ventricular topology (L-ventricular loop) and its prevalence in DILV?

Answer 6

65% of DILV cases exhibit left-handed ventricular topology.

In this topology, the smooth ventricular septum is anterior and leftward near the outlet chamber.

Question 7

What is right-handed ventricular topology (D-ventricular loop) and its prevalence in DILV?

Answer 7

35% of DILV cases exhibit right-handed ventricular topology.

In this topology, the smooth ventricular septum is anterior and rightward.

Question 8

What is the posterior median ridge in the left ventricle?

Answer 8

A large muscle bundle running from base to apex between the AV valves.

This structure is located on the inferior or diaphragmatic wall of the left ventricle.

Question 9

What does the ventricular septal defect (VSD) refer to in DILV?

Answer 9

A defect that can be variable in position, number, and size.

A small communication often obstructs the outflow arising from the outlet chamber.

Question 10

What type of transposition occurs in almost all DILV cases with left-handed ventricular topology?

Answer 10

L-transposition (left and anterior aorta).

This occurs in 65% of DILV cases.

Question 11

What types of transposition are observed in right-handed ventricular topology DILV?

Answer 11

D-transposition (20%) and normally related great arteries (Holmes heart, 15%).

D-transposition features an anterior and rightward aorta.

Question 12

What does DILV stand for?

Answer 12

Double Inlet Left Ventricle

Question 13

What is the most common variant of DILV?

Answer 13

Left-sided subaortic incomplete/hypoplastic RV cavity

Question 14

What is the morphology of the left ventricle in DILV?

Answer 14

Right-sided morphologic left ventricle

Question 15

What condition results from severe overriding and straddling of the left-sided AV valve?

Answer 15

Commitment of the valve to the left ventricle

Question 16

What is the size range of the morphologic right ventricular cavity in DILV?

Answer 16

Severely hypoplastic to 75% of the left ventricle

Question 17

What provides communication to the hypoplastic left-sided right ventricle?

Answer 17

Ventricular Septal Defect (VSD)

Question 18

Fill in the blank: Subaortic obstruction can be associated with a _______.

Answer 18

restrictive VSD

Question 19

What does DILV stand for?

Answer 19

Double Inlet Left Ventricle

DILV is a congenital heart defect characterized by the presence of two atrioventricular valves leading to a single functional ventricle.

Question 20

What is the orientation of the aorta in DILV with anterior and rightward aorta?

Answer 20

Rightward and anterior

This orientation refers to the positioning of the aorta in relation to the heart’s anatomy.

Question 21

What type of ventricular topology is associated with DILV?

Answer 21

Right-handed ventricular topology

This term describes the structural arrangement of the heart’s ventricles in DILV.

Question 22

What is the condition of the right-sided hypoplastic subaortic cavity?

Answer 22

Incomplete/hypoplastic

This indicates that the right ventricle cavity is underdeveloped and not fully formed.

Question 23

What is the morphology of the left ventricle in DILV?

Answer 23

Morphologic left ventricle

This means that the left ventricle is present and has a structure typical of a normal left ventricle.

Question 24

What provides communication to the hypoplastic right ventricle in this condition?

Answer 24

Ventricular Septal Defect (VSD)

A VSD is a defect in the septum dividing the two ventricles, allowing blood flow between them.

Question 25

What obstruction can be associated with a restrictive VSD?

Answer 25

Subaortic obstruction ## Footnote A restrictive VSD can limit blood flow and pressure, potentially leading to obstruction in the outflow tract of the heart.

Question 26

What does DILV stand for?

Answer 26

DILV stands for Double Inlet Left Ventricle.

Question 27

What is another name for DILV with normally related great arteries?

Answer 27

Holmes Heart.

Question 28

Describe the morphology of the right ventricle in DILV.

Answer 28

Right sided hypoplastic subpulmonary incomplete/hypoplastic RV cavity.

Question 29

What is the morphology of the left ventricle in DILV?

Answer 29

Left-sided morphologic left ventricle.

Question 30

What role does the VSD play in DILV?

Answer 30

VSD provides communication into hypoplastic right ventricle.

Question 31

What may the VSD be a substrate for in DILV?

Answer 31

Subpulmonary obstruction.

Question 32

How can the subpulmonary obstruction in DILV be favorable?

Answer 32

It may result in a balanced circulation.

Question 33

Fill in the blank: DILV is associated with _______ right-handed ventricular topology.

Answer 33

normally related great arteries.

Question 34

What is the usual atrial arrangement seen in DILV?

Answer 34

Atrial situs solitus with normal systemic and pulmonary venous connections ## Footnote DILV stands for Double-Inlet Left Ventricle, a type of congenital heart defect.

Question 35

What is the typical condition of the atrial communication in DILV?

Answer 35

Usually small or intact ## Footnote Atrial communication refers to the connection between the atria of the heart.

Question 36

What causes subvalvar obstruction in DILV?

Answer 36

Posterior malalignment of the outlet septum, AV valve tissue, or a fibromuscular ridge ## Footnote AV valve refers to the atrioventricular valve, which includes the mitral and tricuspid valves.

Question 37

What can occur alongside subaortic stenosis in DILV?

Answer 37

Hypoplasia of the aorta with coarctation or arch interruption ## Footnote Coarctation refers to a narrowing of the aorta.

Question 38

What is the typical position of the aortic arch in DILV?

Answer 38

Usually left-sided ## Footnote The aortic arch is the portion of the aorta that bends between the ascending and descending aorta.

Question 39

What is the condition of the branch pulmonary arteries in DILV?

Answer 39

Usually confluent and of normal caliber ## Footnote Confluent means that the pulmonary arteries are joined together or have a common trunk.

Question 40

True or False: The branch pulmonary arteries can be of abnormal caliber in cases of DILV.

Answer 40

False ## Footnote Even in cases of subvalvar and/or valvar pulmonary stenosis, the branch pulmonary arteries remain normal in caliber.