Article: Congenital heart disease

Cross-section of a healthy heart.

Congenital heart disease is heart disease in the newborn, and includes congenital heart defects, congenital arrythmias, and cardiomyopathies. Congenital heart disease, which is also referred to as CHD, is a defect of the heart that exists primarily at birth. CHD can describe a wide variety of different abnormalities affecting the heart. CHD occurs when the heart or blood vessels near the heart does not develop properly before birth. Therefore, the heart does not pump because it is not completely developed. Also the blood flow is obstructed in the heart of the vessels nearby, causing an abnormal flow of blood through the heart. Blood flow obstructions put a strain on the heart muscle causing the heart to work harder and beat faster. Abnormal blood flow usually occurs when there is a hole in the walls of the heart and may be an abnormal connection between two arteries outside the heart.

Causes

CHD has many diverse causes. Some factors are environmental, such as chemicals, drugs, or infection. However, the bulk of CHD is thought to be genetic in nature. Infections such as German measles (i.e. rubella) can produce CHD. Women with diabetes and phenylketonuria are at high risk for their children to be born with this disease. Other causes include the mother's excessive intake of alcohol and illegal drugs while pregnant. There are many genetic conditions which can be a factor in causing CHD, such as DiGeorge syndrome (22q11 deletion syndrome), Holt-Oram syndrome, and Alagille syndrome. Although these factors are known causes of CHD, most are currently unknown. Therefore, most cases of CHD are unknown.

Diagnosis

Mild congenital heart diseases may not be observed or occur until adulthood. The physician or provider will find this through a series of questions in an examination. Echocardiography and cardiac magnetic resonance(MRI) are used to confirm CHD when signs or symptoms occur in the physical examination. An echocardiograph displays images of the heart and the sound waves it makes. It also finds abnormal rhythms or defects of the heart present with CHD. Fetal echocardiography is used to diagnose CHD in utero after 20 weeks of pregnancy. An ultrasound may be used to determine the defects in pregnant women. Cardiac MRI scans and uses magnetic fields and radio waves to determine these defects but is not always necessary in dianosing CHD. A chest x-ray may also be issued to look at the anatomical position of the heart and lungs. A Cat Scan(CT) can also be used to visualize CHD. All of these tests are ways to diagnose CHD by a physician.

Types of congenital heart disease

Patent ductus arteriosus

Main article: Patent ductus arteriosus

The opening of a passageway or temporary blood vessel to carry blood away from the heart to the aorta before birth. This allows blood to go around the lungs which are not yet used. The ductus should close suddenly in the first few hours or days after birth. When it does not close in the newborn, the blood that is supposed to flow through the aorta goes to the lungs. This disease is common is premature infants but rare in full-term infants.

Hypoplastic left heart syndrome

Main article: Hypoplastic left heart syndrome

A condition in which the left side of the heart is not fully developed. This condition is rare but is the most serious of CHD. The blood reaches the aorta, which pumps blood throughout the entire body, only from one ductus. This normally closes within a few days of birth. With this syndrome, the infant seems normal at birth, but as the ductus closes, blood cannot circulate through the aorta and the rest of the body resulting in cyanosis.

Obstruction defects

Heart valves, arteries, and veins become completely or partially blocked when they are narrowing. The most common obstructions are pulmonary valve stenosis, aortic valve stenosis, and coarctation of the aorta. Bicuspid aortic valve and subaortic stenosis are rare. Stenosis is narrowing of valves and arteries. In pulmonary stenosis, the valve does not open making the right ventricle to become overworked. In aortic stenosis, the aortic valve is not formed right and making the valve to narrow. The left ventricle becomes enlarged as it has to work harder to pump blood throughout the body. The aorta is constricted in coarctation of the aorta causing a reduction of blood flow to the lower portion of the body. This causes hypertension in the upper body.

Septal defects

Blood leaks from the left portions of the heart to the right when a baby is born with a hole in the septum. This overflow of blood can cause an enlargement of the heart causing poor circulation. Some common types are atrial septal defect and ventricular septal defect.

Cyanotic defects

Disorders that cause profusion or an insufficient amount of oxyen in the blood pumped throughout the body are called cyanotic defects. Some disorders are truncus arteriosus, total anomalous pulmonary venous return, tetralogy of Fallot, transpositon of the great arteries, and tricuspid atresia. All of these result in bluish-grey discoloration of the skin due to lack of oxygen to the body.

Other defects

• Ebstein's anomaly
• Brugada syndrome
• Marfan syndrome
• DiGeorge Syndrome

Signs and Symptoms

Symptoms and signs are related to the type and severity of the heart defects. Some children have no signs while others may exhibit shortness of breath, cyanosis, chest pain, syncope, sweating, heart murmur, respiratory infections, underdeveloping of limbs and muscles, poor feeding, or poor growth. Most defects cause a whispering sound, or murmur, as blood moves through the heart causing some of these symptoms. All of these symptoms occur at a young age of a child or infant which is typically found during a physical examination.

Treatment

Sometimes CHD improves with no treatment necessary. At other times the defect is so small and does not require any treatment. Most of the time CHD is serious and requires surgery and/or medications. Medications include diuretics which aid the baby in eliminating water, salts, and digoxin, which aids in strengthening the contraction of the heart. This slows the heartbeat and removes some fluid from tissues. Some defects require surgical procedures to repair as much as possible to restore circulation back to normal. In some cases, multiple surgeries are needed to be performed to help balance the circulation.