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.

Presence of a cystic hygroma increases the risk of HLHS in a fetus.

Genetic loci associated with HLHS include GJA1 (connexin 43), HAND1, NKX2.5, 10q22, and 6q23. There is a slight risk of recurrence in future pregnancies, estimated to be 2-4%, which increases to 25% in families with two affected children. This is thought to be mediated by genetic mutations with incomplete penetrance.

HLHS is also associated with several genetic syndromes, including trisomy 13 (Patau syndrome), trisomy 18 (Edwards syndrome), partial trisomy 9, Turner's syndrome (XO), Jacobsen syndrome (11q deletion syndrome), Holt-Oram syndrome, and Smith-Lemli-Opitz syndrome.

Tetralogy of Fallot occurs approximately 400 times per million live births and accounts for 7 to 10% of all congenital heart abnormalities.

As a group, atrial septal defects are detected in one child per 1500 live births. PFOs are quite common (appearing in 10–20% of adults), but asymptomatic, so undiagnosed. ASDs make up 30 to 40% of all congenital heart diseases that are seen in adults.

The ostium secundum atrial septal defect accounts for 7% of all congenital heart lesions. This lesion shows a male:female ratio of 1:2.

Bicuspid aortic valves are the most common cardiac valvular anomaly, occurring in 1–2% of the general population. It is twice as common in males as in females.

Bicuspid aortic valve is a heritable condition, with a demonstrated association with mutations in the NOTCH1 gene. Its heritability (formula_1) is as high as 89%. Both familial clustering and isolated valve defects have been documented. The incidence of bicuspid aortic valve can be as high as 10% in families affected with the valve problem..Recent studies suggest that BAV is an autosomal dominant condition with incomplete penetrance. Other congenital heart defects are associated with bicuspid aortic valve at various frequencies, including coarctation of the aorta.

Untreated, tetralogy of Fallot rapidly results in progressive right ventricular hypertrophy due to the increased resistance caused by narrowing of the pulmonary trunk. This progresses to heart failure which begins in the right ventricle and often leads to left heart failure and dilated cardiomyopathy. Mortality rate depends on the severity of the tetralogy of Fallot. If left untreated, TOF carries a 35% mortality rate in the first year of life, and a 50% mortality rate in the first three years of life. Untreated TOF also causes delayed growth and development, including delayed puberty.

Patients who have undergone total surgical repair of tetralogy of Fallot have improved hemodynamics and often have good to excellent cardiac function after the operation with some to no exercise intolerance (New York Heart Association Class I-II). Surgical success and long-term outcome greatly depend on the particular anatomy of the patient and the surgeon's skill and experience with this type of repair.

Ninety percent of people with total repair as babies develop a progressively leaky pulmonary valve later in life. It is recommended that they follow up at a specialized adult congenital heart disease center.

Down syndrome is often associated with AVCD. Other risk factors include: having a parent with a congenital heart defect, alcohol use while pregnant, uncontrolled diabetes treatment during pregnancy and some medications during pregnancy.

This type of congenital heart defect is associated with patients with Down syndrome (trisomy 21) or heterotaxy syndromes. 45% of children with Down syndrome have congenital heart disease. Of these, 35–40% have AV septal defects. Similarly, one-third of all children born with AVSDs also have Down syndrome.

A study also showed that there is also an increased risk of atrioventricular canal in patients who suffer from Noonan syndrome. The pattern seen in those patients with Noonan syndrome differ from those patients who have Down syndrome in that "partial" AVCD is more prevalent in those who suffer from NS, where as those who suffer from down syndrome show a prevalence of the "complete" form of AVCD.

Hypoplastic right heart syndrome is less common than hypoplastic left heart syndrome which occurs in 4 out of every 10,000 births. [3].

This rare anomaly requires prenatal diagnosis since it needs immediate and emergency treatment. Pregnant women whose pregnancy is complicated with this anomaly should be referred to a level 3 hospital with pediatric cardiology and pediatric cardiothoracic surgical team.[3]

It can be associated with aortic stenosis.

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.

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)

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.

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

When there are holes in the septum that divide the four chambers of the heart the oxygen-rich blood and oxygen-poor blood mix this creates more stress on the heart to pump blood to where oxygen is needed. As a result, you get enlargement of the heart, heart failure (being unable to adequately supply body with needed oxygen, pulmonary hypertension, and pneumonia.

The development of pulmonary hypertension is very serious. And this because the left ventricle is weakened due to its overuse. When this happens, the pressure backs up into the pulmonary veins and the lungs. This type of damage is irreversible which is why immediate treatment is recommended after diagnosis.

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

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.

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

The following table includes the main types of valvular stenosis and regurgitation. Major types of valvular heart disease not included in the table include mitral valve prolapse, rheumatic heart disease and endocarditis.

The Registry has been enrolling new patients from participating institutions that are member of the Congenital Heart Surgeons' Society. Hospitals from across North America continue to join the study group and enroll patients. Over 140 patients with AAOCA have been enrolled by June 2011, making it the largest cohort ever assembled of this anomaly.

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.

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.

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.

Hypertension is defined when a patient's blood pressure in the arm exceeds 140/90 mmHg under normal conditions. This is a severe problem for the heart and can cause many other complications. In a study of 120 coarctation repair recipients done in Groningen, The Netherlands, twenty-nine patients (25%) experienced hypertension in the later years of life due to the repair. While hypertension has many different factors that lead to this stage of blood pressure, people who have had a coarctation repair — regardless of the age at which the operation was performed — are at much higher risk than the general public of hypertension later in life. Undetected chronic hypertension can lead to sudden death among coarctation repair patients, at higher rates as time progresses.

Angioplasty is a procedure done to dilate an abnormally narrow section of a blood vessel to allow better blood flow. This is done in a cardiac catheterization laboratory. Typically taking two to three hours, the procedure may take longer but usually patients are able to leave the hospital the same day. After a coarctation repair 20-60% of infant patients may experience reoccurring stenosis at the site of the original operation. This can be fixed by either another coarctectomy.

Coronary artery disease (CAD) is a major issue for patients who have undergone a coarctation repair. Many years after the procedure is done, heart disease not only has an increased chance of affecting coarctation patients, but also progresses through the levels of severity at an alarmingly increased rate. In a study conducted by Mare Cohen, MD, et al., one fourth of the patients who experienced a coarctation died of heart disease, some at a relatively young age.

Clinical criteria are used in most studies when defining recurrence of coarctation (recoarctation) when blood pressure is at a difference of >20 mmHg between the lower and upper limbs. This procedure is most common in infant patients and is uncommon in adult patients. In a study conducted by Koller et al., 10.8% of infant patients underwent recoarctations at less than two years of age while another 3.1% of older children received a recoarctation.

People who have had a coarctation of the aorta are likely to have bicuspid aortic valve disease. Between 20% and 85% of patients are affected with this disease. Bicuspid aortic valve disease is a big contributor to cardiac failure, which in turn makes up roughly 20% of late deaths to coarctation patients.

Anomalous origin of the right coronary artery originating from the pulmonary trunk (ARCAPA) is a rare but potentially fatal anomaly. The goal of surgical therapy is establishment of a physiologic bi-coronary circulation.