Dextro-Transposition of the great arteries
Encyclopedia
dextro-Transposition of the great arteries (d-Transposition of the great arteries, dextro-TGA, or d-TGA), sometimes also referred to as complete transposition of the great arteries, is a birth defect in the large arteries of the heart. The primary arteries (the aorta
and the pulmonary artery
) are transposed.
It is called a cyanotic
congenital heart defect
(CHD) because the newborn infant turns blue from lack of oxygen.
In segmental analysis
, this condition is described as ventriculoarterial discordance with atrioventricular concordance, or just ventriculoarterial discordance.
d-TGA is often referred to simply as transposition of the great arteries (TGA); however, TGA is a more general term which may also refer to levo-transposition of the great arteries
(l-TGA).
Another term commonly used to refer to both d-TGA and l-TGA is transposition of the great vessels
(TGV), although this term might have an even broader meaning than TGA.
, oxygen
-depleted ("blue") blood is pumped from the right side of the heart
, through the pulmonary artery, to the lung
s where it is oxygenated. The oxygen-rich ("red") blood then returns to the left heart
, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle
itself.
With d-TGA, blue blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps red blood continuously back into the lungs through the pulmonary artery. In effect, two separate "circular" (parallel) circulatory systems are created, rather than the "figure 8
" (in series) circulation of a normal cardio-pulmonary system.
s affect the relative positions of the aorta and pulmonary artery. In the majority of d-TGA cases, the aorta is anterior and to the right of the pulmonary artery, but it can also be directly anterior or anterior and to the left. The aorta and pulmonary artery can also be side by side, with aorta on either side. This is a less common variant, and with this arrangement, an unusual coronary artery pattern is common. There are also some cases with aorta to the right and posterior to the pulmonary artery.
such as atrial septal defect
(ASD) including patent foramen ovale (PFO), ventricular septal defect
(VSD), and patent ductus arteriosus
(PDA). Stenosis
of valves
or vessels
may also be present.
When no other heart defects are present it is called 'simple' d-TGA; when other defects are present it is called 'complex' d-TGA.
Although it may seem illogical, complex d-TGA presents better chance of survival and less developmental
risks than simple d-TGA, as well as usually requiring fewer invasive palliative procedures. This is because the left-to-right and bidirectional shunting
caused by the defects common to complex d-TGA allow a higher amount of oxygen-rich blood to enter the systemic circulation
. However, complex d-TGA may cause a very slight increase to length and risk of the corrective surgery
, as most or all other heart defects will normally be repaired at the same time, and the heart becomes "irritated
" the more it is manipulated.
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
and the pulmonary artery
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
) are transposed.
It is called a cyanotic
Cyanotic heart defect
A cyanotic heart defect is a group-type of congenital heart defects . The patient appears blue , due to deoxygenated blood bypassing the lungs and entering the systemic circulation...
congenital heart defect
Congenital heart defect
A congenital heart defect is a defect in the structure of the heart and great vessels which is present at birth. Many types of heart defects exist, most of which either obstruct blood flow in the heart or vessels near it, or cause blood to flow through the heart in an abnormal pattern. Other...
(CHD) because the newborn infant turns blue from lack of oxygen.
In segmental analysis
Segmental analysis (biology)
Segmental analysis is a method of anatomical analysis for describing the connective morphology of the human body. Instead of describing anatomy in terms of spatial relativity, as in the anatomical position method, segmental analysis describes anatomy in terms of which organs, tissues, etc...
, this condition is described as ventriculoarterial discordance with atrioventricular concordance, or just ventriculoarterial discordance.
d-TGA is often referred to simply as transposition of the great arteries (TGA); however, TGA is a more general term which may also refer to levo-transposition of the great arteries
Levo-Transposition of the great arteries
levo-Transposition of the great arteries , also commonly referred to as congenitally corrected transposition of the great arteries , is an acyanotic congenital heart defect in which the primary arteries are transposed, with the aorta anterior and to...
(l-TGA).
Another term commonly used to refer to both d-TGA and l-TGA is transposition of the great vessels
Transposition of the great vessels
Transposition of the great vessels is a group of congenital heart defects involving an abnormal spatial arrangement of any of the primary blood vessels: superior and/or inferior vena cavae , pulmonary artery, pulmonary veins, and aorta...
(TGV), although this term might have an even broader meaning than TGA.
Description
In a normal heartHeart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
-depleted ("blue") blood is pumped from the right side of the heart
Right heart
Right heart is a term used to refer collectively to the right atrium and right ventricle of the heart; occasionally, this term is intended to reference the right atrium, right ventricle, and the pulmonary trunk collectively....
, through the pulmonary artery, to the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s where it is oxygenated. The oxygen-rich ("red") blood then returns to the left heart
Left heart
Left heart is a term used to refer collectively to the left atrium and left ventricle of the heart; occasionally, this term is intended to reference the left atrium, left ventricle, and the aorta collectively....
, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
itself.
With d-TGA, blue blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps red blood continuously back into the lungs through the pulmonary artery. In effect, two separate "circular" (parallel) circulatory systems are created, rather than the "figure 8
Lemniscate
In algebraic geometry, a lemniscate refers to any of several figure-eight or ∞ shaped curves. It may refer to:*The lemniscate of Bernoulli, often simply called the lemniscate, the locus of points whose product of distances from two foci equals the square of half the interfocal distance*The...
" (in series) circulation of a normal cardio-pulmonary system.
Arterial spatial relationships
Differences in the shape of the atrial septum and/or ventricular outflow tractVentricular outflow tract
A ventricular outflow tract is a portion of either the left ventricle or right ventricle of the heart through which blood passes in order to enter the great arteries....
s affect the relative positions of the aorta and pulmonary artery. In the majority of d-TGA cases, the aorta is anterior and to the right of the pulmonary artery, but it can also be directly anterior or anterior and to the left. The aorta and pulmonary artery can also be side by side, with aorta on either side. This is a less common variant, and with this arrangement, an unusual coronary artery pattern is common. There are also some cases with aorta to the right and posterior to the pulmonary artery.
Simple and complex d-TGA
d-TGA is often accompanied by other heart defects, the most common type being intracardiac shuntsShunt (medical)
In medicine, a shunt is a hole or a small passage which moves, or allows movement of fluid from one part of the body to another. The term may describe either congenital or acquired shunts; and acquired shunts may be either biological or mechanical.* Cardiac shunts may be described as...
such as atrial septal defect
Atrial septal defect
Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...
(ASD) including patent foramen ovale (PFO), ventricular septal defect
Ventricular septal defect
A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...
(VSD), and patent ductus arteriosus
Patent ductus arteriosus
Patent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain...
(PDA). Stenosis
Stenosis
A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure.It is also sometimes called a stricture ....
of valves
Heart valve
A heart valve normally allows blood flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart...
or vessels
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
may also be present.
When no other heart defects are present it is called 'simple' d-TGA; when other defects are present it is called 'complex' d-TGA.
Although it may seem illogical, complex d-TGA presents better chance of survival and less developmental
Child development
Child development stages describe theoretical milestones of child development. Many stage models of development have been proposed, used as working concepts and in some cases asserted as nativist theories....
risks than simple d-TGA, as well as usually requiring fewer invasive palliative procedures. This is because the left-to-right and bidirectional shunting
Cardiac shunt
Cardiac shunts is when the blood flow follows a pattern in the heart that deviates from the normal circuit of the circulatory system. It may be described as right-left, left-to-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic. The direction may be controlled by left...
caused by the defects common to complex d-TGA allow a higher amount of oxygen-rich blood to enter the systemic circulation
Systemic circulation
Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart. This physiologic theory of circulation was first described by William Harvey...
. However, complex d-TGA may cause a very slight increase to length and risk of the corrective surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, as most or all other heart defects will normally be repaired at the same time, and the heart becomes "irritated
Irritation
Irritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...
" the more it is manipulated.