Complete vascular rings represent about 0.5-1% of all congenital cardiovascular malformations. The majority of these are double aortic arches.

There is no known gender preference, i.e. males and females are about equally affected. There is also no known ethnic or geographic disposition.

Associated cardiovascular anomalies are found in 10-15% of patients. These include:

- Atrial septal defect (ASD)

- Ventricular septal defect (VSD)

- Patent ductus arteriosus (PDA)

- Tetralogy of Fallot (ToF)

- Transposition of the great arteries (D-TGA)

Some recent research has suggested that a proportion of cases of migraine may be caused by PFO. While the exact mechanism remains unclear, closure of a PFO can reduce symptoms in certain cases. This remains controversial; 20% of the general population has a PFO, which for the most part, is asymptomatic. About 20% of the female population has migraines, and the placebo effect in migraine typically averages around 40%. The high frequency of these facts finding statistically significant relationships between PFO and migraine difficult (i.e., the relationship may just be chance or coincidence). In a large randomized controlled trial, the higher prevalence of PFO in migraine patients was confirmed, but migraine headache cessation was not more prevalent in the group of migraine patients who underwent closure of their PFOs.

Preexisting diabetes mellitus of a pregnant mother is a risk factor that has been described for the fetus having TGV.

Persistent truncus arteriosus is a rare cardiac abnormality that has a prevalence of less than 1%.

A PDA is sometimes idiopathic. Known risk factors include:

- Preterm birth

- Congenital rubella syndrome

- Chromosomal abnormalities (e.g., Down syndrome)

- Genetic conditions such as Loeys-Dietz syndrome (would also present with other heart defects), Wiedemann-Steiner syndrome, and CHAR syndrome.

In terms of the cause of pulmonary atresia, there is uncertainty as to what instigates this congenital heart defect. Potential risk factors that can cause this congenital heart defect are those the pregnant mother may come in contact with, such as:

- Certain medications

- Diet

- Smoking

Venous thrombus (clots in the veins) are quite common. Embolizations (dislodgement of thrombi) normally go to the lung and cause pulmonary emboli. In an individual with ASD, these emboli can potentially enter the arterial system, which can cause any phenomenon attributed to acute loss of blood to a portion of the body, including cerebrovascular accident (stroke), infarction of the spleen or intestines, or even a distal extremity (i.e., finger or toe).

This is known as a paradoxical embolus because the clot material paradoxically enters the arterial system instead of going to the lungs.

Good peer to peer support is available on Facebook. For new and existing parents The group, Transposition of the Great Arteries

For ADULT survivors of D-TGA the Facebook group Mustard or Senning Survivors, gathers several hundred global survivors in their 20s to 50s into a single community. Supporting ADULTS born with TGA that have had a Mustard, Senning, Rastelli or Nikaidoh Heart Procedure *This group is not recommended for Parents of Arterial Switch children.

VSDs are the most common congenital cardiac abnormalities. They are found in 30-60% of all newborns with a congenital heart defect, or about 2-6 per 1000 births. During heart formation, when the heart begins life as a hollow tube, it begins to partition, forming septa. If this does not occur properly it can lead to an opening being left within the ventricular septum. It is debatable whether all those defects are true heart defects, or if some of them are normal phenomena, since most of the trabecular VSDs close spontaneously. Prospective studies give a prevalence of 2-5 per 100 births of trabecular VSDs that close shortly after birth in 80-90% of the cases.

Since PDA is usually identified in infants, it is less common in adults, but it can have serious consequences, and is usually corrected surgically upon diagnosis.

For newborns with transposition, prostaglandins can be given to keep the ductus arteriosus open which allows mixing of the otherwise isolated pulmonary and systemic circuits. Thus oxygenated blood that recirculates back to the lungs can mix with blood that circulates throughout the body. The arterial switch operation is the definitive treatment for dextro- transposition. Rarely the arterial switch is not feasible due to particular coronary artery anatomy and an atrial switch operation is preferred.

Little is known regarding the exact causes of aortic arch anomalies. However, the association with chromosome 22q11 deletion (CATCH 22) implies that a genetic component is likely in certain cases. Esophageal atresia also occurs in some patients with double aortic arch.

DORV affects between 1% and 3% of people born with congenital heart defects.

Chromosomal abnormalities were reported in about 40% of reported cases in the medical literature.

It was Bex who introduced in 1980 the possibility of aortic translocation. But Nikaidoh has put the procedure in practice in 1984. It results in an anatomical normal heart, even better than with an ASO, because also the cones are switched instead of only the arteries as with an ASO.

It has as contra-indication coronary anomalies.

The prognosis for pulmonary atresia varies for every child, if the condition is left uncorrected it may be fatal, but the prognosis has greatly improved over the years for those with pulmonary atresia. Some factors that affect how well the child does include how well the heart is beating, and the condition of the blood vessels that supply the heart. Most cases of pulmonary atresia can be helped with surgery, if the patient's right ventricle is exceptionally small, many surgeries will be needed in order to help stimulate normal circulation of blood to the heart.If uncorrected, babies with this type of congenital heart disease may only survive for the first few days of life. Many children with pulmonary atresia will go on to lead normal lives, though complications such as endocarditis, stroke and seizures are possible.

Persistent truncus arteriosus (or Patent truncus arteriosus or Common arterial trunk), is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus fails to properly divide into the pulmonary trunk and aorta. This results in one arterial trunk arising from the heart and providing mixed blood to the coronary arteries, pulmonary arteries, and systemic circulation.

Congenital VSDs are frequently associated with other congenital conditions, such as Down syndrome.

A VSD can also form a few days after a myocardial infarction (heart attack) due to mechanical tearing of the septal wall, before scar tissue forms, when macrophages start remodeling the dead heart tissue.

The causes of congenital VSD (ventricular septal defect) include the

incomplete looping of the heart during days 24-28 of development. Faults with NKX2.5 gene are usually associated with isolated (non syndromic) ASD in humans when one copy is missing.

Known environmental factors include certain infections during pregnancy such as Rubella, drugs (alcohol, hydantoin, lithium and thalidomide) and maternal illness (diabetes mellitus, phenylketonuria, and systemic lupus erythematosus).

Being overweight or obese increases the risk of congenital heart disease. Additionally, as maternal obesity increases, the risk of heart defects also increases. A distinct physiological mechanism has not been identified to explain the link between maternal obesity and CHD, but both prepregnancy folate deficiency and diabetes have been implicated in some studies.

l-TGA is often accompanied by other heart defects, the most common type being shunts 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' l-TGA; when other defects are present it is called 'complex' l-TGA.

In a normal heart, oxygen-depleted ("deoxygenated") blood is pumped from the right atrium into the right ventricle, then through the pulmonary artery to the lungs where it is oxygenated. The oxygen-rich ("oxygenated") blood then returns, via the pulmonary veins, to the left atrium from which it is pumped into the left ventricle, then through the aorta to the rest of the body, including the heart muscle itself.

With l-TGA, deoxygenated blood is pumped from the right atrium into the morphological left ventricle (which lies on the right side of the heart), then through the pulmonary artery to the lungs. The oxygenated blood then returns, via the pulmonary veins, to the left atrium from which it is pumped into the morphological right ventricle, then through the aorta.

DORV occurs in multiple forms, with variability of great artery position and size, as well as of ventricular septal defect (VSD) location. It can occur with or without transposition of the great arteries. The clinical manifestations are similarly variable, depending on how the anatomical defects affect the physiology of the heart, in terms of altering the normal flow of blood from the RV and left ventricle (LV) to the aorta and pulmonary artery. For example:

The cause of congenital heart disease may be genetic, environmental, or a combination of both.

Vein of Galen malformations are devastating complications. Studies have shown that 77% of untreated cases result in mortality. Even after surgical treatment, the mortality rate remains as high as 39.4%. Most cases occur during infancy when the mortality rates are at their highest. Vein of Galen malformations are a relatively unknown affliction, attributed to the rareness of the malformations. Therefore, when a child is diagnosed with a faulty Great Cerebral Vein of Galen, most parents know little to nothing about what they are dealing with. To counteract this, support sites have been created which offer information, advice, and a community of support to the afflicted (, ).

Left to right shunting heart defects include:

- Ventricular septal defect (VSD) (30% of all congenital heart defects)

- Atrial septal defect (ASD)

- Atrioventricular septal defect (AVSD)

- Patent ductus arteriosus (PDA)

- Previously, Patent ductus arteriosus (PDA) was listed as acyanotic but in actuality it can be cyanotic due to pulmonary hypertension resulting from the high pressure aorta pumping blood into the pulmonary trunk, which then results in damage to the lungs which can then result in pulmonary hypertension as well as shunting of blood back to the right ventricle. This consequently results in less oxygenation of blood due to alveolar damage as well as oxygenated blood shunting back to the right side of the heart, not allowing the oxygenated blood to pass through the pulmonary vein and back to the left atrium.

- (Edit - this is called Eisenmenger's syndrome and can occur with Atrial septal defect and ventricular septal defect as well (actually more common in ASD and VSD) therefore PDA can still be listed as acyanotic as, acutely, it is)

Others:

- levo-Transposition of the great arteries (l-TGA)

Acyanotic heart defects without shunting include:

- Pulmonary stenosis (a narrowing of the pulmonary valve)

- Aortic stenosis

- Coarctation of the aorta

An acyanotic heart defect, also known as non-cyanotic heart defect, is a class of congenital heart defects. In these, blood is shunted (flows) from the left side of the heart to the right side of the heart due to a structural defect (hole) in the interventricular septum. People often retain normal levels of oxyhemoglobin saturation in systemic circulation.

This term is outdated, because a person with an acyanotic heart defect may show cyanosis (turn blue due to insufficient oxygen in the blood).