Septal Defect | Health Encyclopedia: Septal Defect

Septal Defect: From 3 Different Sources

A congenital heart abnormality in which there is a hole in the septum between the left and right ventricles of the heart or, more rarely, between the left and right atria. Usually, the cause is unknown. The hole allows freshly oxygenated blood to mix with deoxygenated blood in the heart.

A small defect has little or no effect. A large ventricular hole may cause heart failure to develop 6–8 weeks after birth, causing breathlessness and feeding difficulties. A large atrial defect may never cause heart failure, but there may be fatigue on exertion. Pulmonary hypertension may develop in both types of defect. Diagnosis may be aided by a chest X-ray, ECG, or echocardiography.

Atrial holes are repaired surgically if they cause symptoms or if complications develop.

As the child grows, small ventricular holes often become smaller, or even close, on their own.

A ventricular defect that is causing heart failure is treated with diuretics and digitalis drugs.

If the hole does not close spontaneously, it may be repaired by open heart surgery.

Health Source: BMA Medical Dictionary
Author: The British Medical Association

A congenital abnormality of the HEART affecting about 260 babies in every 100,000, in which there is a hole in the septum – the dividing wall – between the left and right sides of the heart. The effects of the defect depend upon its size and position. A defect in the wall between the atria (upper chambers of the heart) is called an atrial septal defect, and that between the ventricles, a ventricular septal defect – the most common form (25 per cent of all defects). Both defects allow blood to circulate from the left side of the heart, where pressures are highest, to the right. This abnormal ?ow of blood is described as a ‘shunt’ and the result is that too much blood ?ows into the lungs. PULMONARY HYPERTENSION occurs and, if the shunt is large, heart failure may develop. A small septal defect may not need treatment but a large one will need to be repaired surgically.

Health Source: Medical Dictionary
Author: Health Dictionary

a hole in the partition (septum) between the left and right halves of the heart. This abnormal communication is usually congenital due to an abnormality of heart development in the fetus, but can occasionally occur as a complication of *myocardial infarction. It may be found between the two atria (see atrial septal defect) or between the ventricles (see ventricular septal defect). A septal defect permits abnormal circulation of blood from the left side of the heart, where pressures are higher, to the right. This abnormal circulation is called a shunt and results in excessive blood flow through the lungs. *Pulmonary hypertension and *heart failure may occur with large shunts. A heart *murmur is normally present. Large defects are closed surgically or by using percutaneous catheter techniques (see atrial septal defect), but small defects do not require treatment.

Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Atrial Septal Defect

See HEART, DISEASES OF – Congenital heart disease.... atrial septal defect

Ventricular Septal Defect

An inherited defect of the HEART. The septum (partition) separating the two ventricles is pierced by a hole which, if large, results in blood being diverted to the LUNGS at a greater pressure than normal. This may lead to irreversible PULMONARY HYPERTENSION, which early surgical intervention (repair of the septal defect) should prevent. A quarter of patients with VSD have other cardiac defects. Half of the defects seal themselves spontaneously.... ventricular septal defect

Neural Tube Defects

Congenital abnormalities resulting from the failure of the NEURAL TUBE to form normally. The resulting conditions include SPINA BIFIDA, MENINGOCELE and defects in the bones of the SKULL.... neural tube defects

Defective Blood Formation

This is the main cause of anaemia in infections. The micro-organism responsible for the infection has a deleterious e?ect upon the blood-forming organs, just as it does upon other parts of the body.

Toxins. In conditions such as chronic glomerulonephritis (see KIDNEYS, DISEASES OF) and URAEMIA there is a severe anaemia due to the e?ect of the disease upon blood formation.

Drugs. Certain drugs, such as aspirin and the non-steroidal anti-in?ammatory drugs, may cause occult gastrointestinal bleeding.... defective blood formation

Limb Defects

Incomplete development of one or more limbs at birth.

Limb defects are rare and may be inherited or form part of a syndrome.

In a condition called phocomelia, hands, feet, or tiny finger- or toe-buds are attached to limb stumps or grow directly from the trunk.

The sedative drug thalidomide, when taken by pregnant women, is known to have caused phocomelia in fetuses.... limb defects

Neural Tube Defect

A developmental failure affecting the spinal cord or brain of the embryo. The most serious defect is anencephaly (total lack of a brain), which is fatal. More common is spina bifida, in which the vertebrae do not form a complete ring around the spinal cord. Spina bifida can occur anywhere on the spine, but it is most common in the lower back.

There are different forms of spina bifida. In spina bifida occulta, the only defect is a failure of the fusion of the bony arches behind the spinal cord, which may not cause any problems. When the bone defect is more extensive, there may be a meningocele, a protrusion of the meninges, or a myelomeningocele, a malformation of the spinal cord. Myelomeningocele is likely to cause severe handicap, with paralysis of the legs, loss of sensation in the lower body, hydrocephalus, and paralysis of the anus and bladder, causing incontinence. Associated problems include cerebral palsy, epilepsy, and mental handicap.

Surgery is usually performed a few days after birth. In mild cases, the defect can usually be corrected, but in myelomeningocele, some handicap will remain.

Genetic factors play a part in neural tube defects, which show multifactorial inheritance. Couples who have had an affected child or who have a family history of neural tube defects should seek genetic counselling. The risk of a neural tube defect occurring can be substantially reduced if the mother takes folic acid supplements for a month before conception and during the early part of the pregnancy.

Ultrasound scanning and amniocentesis allow accurate antenatal testing for neural tube defects.... neural tube defect