There are several distinct main types of CHD, but many have multiple variations depending on the individual’s unique anatomy

1. Aortic valve defects – an abnormality of the valve that leads from the left ventricle to the aorta.
   1. Aortic Valve Stenosis (AVS) – a narrowing of the opening of the aortic valve. This narrowing restricts blood flow from the left ventricle out the aorta to the body.
   2. Bicuspid Aortic Valve (BAV)- in a normal heart the aortic valve is comprised of three leaflets which open and close to regulate blood flow. Bicuspid means the aortic valve only has 2 leaflets. With this defect the valve does not function perfectly, but may function for years without problems or needed medical intervention. BAV is an inherited form of CHD.
   3. Unicuspid Aortic Valve (UAV) – a more severe defect where the aortic valve has a pinhole or slit-like opening
2. Arrhythmias – an abnormal heart
   1. Bradycardia – a slow heart rate, less than 60 beats per minute. What’s too slow for an individual varies from person to person. A trained adult athlete may have a slower heart rate that does not cause problems and is normal for them.
   2. Tachycardia – an abnormally fast heart rate, a resting rate greater than 100 beats per minute in adults. Infants and younger children will have higher resting heart rates than adults.
   3. Abnormal rhythm – when the heart has an irregular beat
   4. Heart Block – an abnormal heart rhythm when the heart’s natural pacemaker is blocked. In heart block the heart beats too slow due to electrical signals that tell the heart to beat being partially or completely blocked.
3. Atrial Septal Defect (ASD) – a “hole” between the atria or top two chambers of the heart. This defect allows oxygen-rich blood to leak into the oxygen-poor blood chambers in the heart.
4. Coarctation of the Aorta (CoA) – A congenital narrowing of the aorta, the main artery that conducts blood from the heart to the body.
   1. Long-segment coarctation – in most a cases a “discreet” or small section of the aorta is narrowed in babies with CoA. In more rare incidences a longer segment of the aorta may be narrowed.
   2. Recurrent coarctation – when narrowing reoccurs after corrective surgery or other intervention
   3. Interrupted aortic arch – complete coarctation of the aorta or when there is a gap/discontinuation between the ascending and descending portions of the aorta.
5. Coronary Artery Abnormalities
   1. Anomalous Coronary Artery – The malformation is often related to the origin of the coronary artery. However, there may be other defective areas in the coronary artery. ACA may also occur along with other congenital heart defects. This condition may also be called congenital artery anomaly (CAA).
   2. Anomalous Aortic – Origin of the Coronary Artery (AAOCA) – Anomalous aortic origin of a coronary artery (AAOCA) is a rare condition in which both of the coronary arteries arise from the same aortic sinus. In a normal heart, the left coronary artery arises from the left aortic sinus and the right coronary artery from the right aortic sinus. In AAOCA, one of the coronary arteries takes off from the aorta (the large blood vessel that brings blood to the body) from the wrong side, and is routed through or around the heart in a way that can restrict blood flow to the heart muscle or cause a potentially lethal heart rhythm. On occasion, there is only one coronary artery that supplies the heart with blood.
   3. Anomalous Left Coronary Artery arising from the Pulmonary Artery (ALCAPA) – When the left coronary artery (LPA), which carries blood to the heart muscle, begins from the pulmonary artery instead of the aorta.
6. Complete Atrioventricular Canal Defect (AVSD) – A large hole in center of the heart affecting all four chambers where they would normally be divided. When a heart is properly divided, the oxygen-rich blood from the lungs does not mix with the oxygen-poor blood from the body. A CAVC allows blood to mix and the chambers and valves do not properly route the blood to each station of circulation.
7. Dextrocardia – Abnormal position of the heart with the chest. The heart normally is in the left chest. When dextrocardia is present, the heart is on the right side. This occurs frequently when a congenital heart defect is present.
8. Ebstein’s Anomaly – a rare defect affecting the tricuspid valve. Commonly, the defect causes the tricuspid valve to leak blood backward into the right atrium. As a result, the right atrium becomes enlarged and if the leakage is severe enough congestive heart failure can occur.
9. Hypertophic Cardiomyopathy – when the heart muscle becomes abnormally thick making it harder to effectively pump blood.
10. Patent Ductus Arteriosus (PDA) – when the small duct, or tube, between the aorta and the pulmonary artery, which normally closes soon after birth, remains open. As a result of its failure to close, blood from the left side of the heart is also pumped into the pulmonary artery and thereby into the lungs. This defect is sometimes called simply patent, or open, ductus.
11. Pulmonary Valve Defects
    1. Pulmonary valve stenosis – A narrowing of the pulmonary valve, which is situated between the right lower chamber and the pulmonary artery.
    2. Pulmonary Atresia – A malformation of the pulmonary valve in which the valve opening fails to develop. The valve is completely closed thereby obstructing the outflow of blood from the heart to the lungs. The pulmonary valve is located on the right side of the heart between the right ventricle and pulmonary artery.
12. Pulmonary Vein Defects
    1. Total Anomalous Pulmonary Venous Return (TAPVR) – when the veins bringing blood back from the lungs don’t connect to the left atrium like usual. Instead they go to the heart by way of abnormal (anomalous) connection.
       1. Obstructed TAPVR – when the pulmonary veins are too narrow or even closed off at some point
       2. Unobstructed TAPVR
    2. Partial Anomalous Pulmonary Venous Return (PAPVR)- where one or two pulmonary veins return blood to the right atrium instead of the left atrium.
13. Single Ventricle Defects – Rare disorders affecting one lower chamber of the heart. The chamber may be smaller, underdeveloped, or missing a valve.
    1. Hypoplastic Left Heart Syndrome (HLHS) – An underdeveloped left side of the heart. The aorta and left ventricle are too small and the holes in the artery and septum did not properly mature and close.
       1. Shone’s Complex – also known as Shone’s syndrome is the combination of stenotic heart lesions. Commonly, coarctation of the aorta, sub-valvular aortic stenosis, a supra-valvular mitral membrane and a parachute mitral valve (both mitral leaflets attaching to one papillary muscle instead of two) are present.
    2. Double Outlet Left Ventricle – a very rare birth defect in children. It occurs when the aorta and pulmonary artery both exit from the left ventricle. The only pathway for blood to flow into the lungs is a hole that connects the two ventricles (ventricle septal defect).
    3. Double Outlet Right Ventricle – where both of the great arteries (the aorta and the pulmonary) connect to the right ventricle.
    4. Double Inlet Right Ventricle – occurs when both great arteries, the aorta and pulmonary artery, attach to the right ventricle. No arteries, or only part of the aorta, will be attached to the left ventricle. This condition is always accompanied by ventricular septal defect (VSD), which is a hole in the septum that divides the left and right ventricle.
    5. Hypoplastic Right Heart Syndrome (HRHS) – a condition that is even more rare than Hypoplastic Left Heart Syndrome (HLHS). HRHS refers to the underdevelopment of the right side structures of the heart, which means that the chambers, valves and related blood vessels on the right side of the heart are malformed.
       1. Tricuspid Atresia – There is no tricuspid valve in the heart so blood cannot flow from the body into the heart in the normal way. The blood is not being properly refilled with oxygen it does not complete the normal cycle of body-heart-lungs-heart-body.
       2. Double Inlet Left Ventricle (DILV) – a congenital defect in which the left and right atria of the heart are connected to the same ventricle.
14. Tetralogy of Fallot – A complex “tetra” or set of 4 defects that occur together: 1) an opening in the wall between the lower heart chambers (Ventricle Septal Defect), 2) a narrowing of the pulmonary valve (stenosis) and the muscular area just beneath it, 3) thickening (hypertrophy) of the right ventricle and 4) abnormal position of the great artery (aorta).
15. Transposition of the Great Arteries (TGA) When the aorta arises from the right, rather than left, ventricle and the pulmonary artery arises from the left, rather than the right, ventricle. Thus the right heart pumps unoxygenated blood from the body through the aorta and back to the body, and the left heart pumps oxygenated blood from the lungs back to the lungs. Only if there is a sizeable hole between right and left chambers, called a septal defect, or a channel between the aorta and pulmonary artery (patent ductus arteriosus) will enough oxygenated blood get pumped to the body to sustain life. Babies with this condition are critically ill and cyanotic and require surgical correction typically in the first days of life.
    1. d-TGA – or dextro-transposition is a birth defect of the heart in which the two main arteries carrying blood out of the heart – the main pulmonary artery and the aorta – are switched in position, or “transposed.”
    2. I-TGA or cc-TGA – a malformation of the heart which causes a reversal in the normal blood flow pattern because the right and left lower chambers of the heart are reversed. The I-transposition, however, is less dangerous than a d-transposition because the great arteries are also reversed. This “double reversal” allows the body to still receive oxygen-rich blood and the lungs to still receive the oxygen-poor blood.
16. Truncus Arteriosus – when a single blood vessel arises from the right and left ventricles instead of the normal two vessels (the pulmonary and aorta). A VSD always occurs along with this condition.
17. Ventricular Septal Defect (VSD) – an abnormal opening in the wall (septum) that divides the two lower chambers of the heart (ventricles) and allows blood from either side of the heart to cross into the opposite ventricle.

Associated disorders:

• Major Arteriopulmonary Collateral Arteries (MAPCAs) – multiple small arteries that develop to supply blood to the lungs when native pulmonary circulation is underdeveloped. These collaterals typically arise from the aorta or other systemic arteries.
• Pulmonary hypertension – High blood pressure, or hypertension, in the blood vessels of the lungs. The most common causes are congenital heart defects.
• Aspleenia – a congenital condition where the baby is born without a spleen
• Heterotaxy Syndrome – a rare but complex condition where many of the body’s major organs, including the heart, develop on the wrong side of the body.
• VACTRL association – VACTRL stands for vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb anomalies. Individuals born with this condition typically exhibit at least 3 of the aforementioned characteristics.