Atrioventricular Septal Defect

Atrioventricular Septal Defect Definition and Meaning

The atrioventricular septal defect is a congenital heart defect. It is a combination of atrial septal defect and ventricular septal defect.

What is an atrioventricular septal defect?

Abbreviated as AVSD by AbbreviationFinder, the atrioventricular septal defect is a congenital heart malformation and one of the most complex congenital heart defects. Since the combination of atrial septal defect and ventricular septal defect creates a connection (shunt), the heart defect is one of the so-called shunt diseases. Shuntvitia are congenital heart defects in which the arterial and venous limbs of the bloodstream are connected to one another.

In the case of atrioventricular septal defect, a double left-right shunt forms. The defect is divided into three categories depending on its severity:

  • complete atrioventricular septal defect
  • partial atrioventricular septal defect
  • Ostium primum defect.

In 35 percent of cases, there are other accompanying heart defects or anomalies of organs.

Causes

The exact cause of the malformation is unknown. Every year around 0.19 per 1000 newborns are affected. Girls and boys get sick about the same frequency. The error occurs very often in connection with Down syndrome. Around 43 percent of all patients with an atrioventricular septal defect also have Down syndrome.

Children are born with a large defect in the heart septum. There is a hole in both the atrial septum (artrial septal defect) and in the septum of the chambers (ventricular septal defect). The heart valve between the left atrium and left ventricle (tricuspid valve) and the valve between the left ventricle and left atrium (mitral valve) are malformed. In addition, the aortic valve is shifted forwards and upwards. The aortic valve lies between the left ventricle and the aorta.

Symptoms, ailments & signs

Whether and which symptoms appear in the newborn depends on the size and location of the defect. The strength of the blood flow, the pressure level in the lungs and the extent of the valve defects also influence the symptoms of the heart defect. The anomalies do not play a role before the birth, as the child is supplied with oxygen-rich blood from the mother. After birth, oxygen is no longer absorbed through the mother, but through the child’s lungs.

To do this, the lungs have to unfold and the pulmonary vessels expand. In the case of a large atrioventricular defect, the high pressure that prevails in the left heart pushes the blood through the wall defect into the right half of the heart. This medical phenomenon is known as a left-right shunt. In the right heart, the extra blood increases the pressure. The blood flows through the pulmonary vessels at increased pressure and thus stresses the lungs.

Both chambers of the heart also have to do significantly more work. The right half of the heart suffers from the increased pressure, the left is affected by the increased blood flow from the lungs. Due to the inability of the AV valve to close, more blood flows back into the left heart. This must also be ejected with each heartbeat. Even within the first few days of life, the child’s heart is so stressed that it leads to heart failure.

The affected children suffer from shortness of breath and show water retention all over their bodies. The skin, eyelids, and liver are swollen. The children become increasingly weak and refuse to drink. In some cases there is a pressure reversal through a protective mechanism.

In this case, oxygen-poor blood from the right heart reaches the left heart through the septal defect. Here the lips and the mouth region are colored blue. If the high blood pressure is fixed in the lungs, surgery can no longer be performed. Children with such fixed pulmonary hypertension have a maximum life expectancy of 10 to 20 years. As a rule, however, the artrioventricular septal defect is detected early.

Diagnosis & course

A heart murmur can be heard during auscultation with the stethoscope as early as the first week. This is caused by the backflow of blood through the defective AV valve. If an atrioventricular septal defect is suspected, an electrocardiogram can be performed. This provides specific information about the heart defect. The X-ray shows a significantly enlarged heart.

The gold standard for fully assessing the severity of the heart defect is echocardiography. If an atrioventricular septal defect is suspected during pregnancy, a prenatal risk assessment can be performed. From the 16th to 20th week of pregnancy, a heart defect can be diagnosed with certainty with this method.

However, the heart defect cannot be detected during normal routine ultrasound examinations. The examinations take place in specially trained perinatal centers.

Complications

In the case of a fully developed atrioventricular septal defect (AVSD), all four heart chambers are connected to one another from birth due to a heart malformation. This means that arterial and venous blood are constantly mixed and the efficiency of the heart’s pumping capacity is greatly reduced.

Complications that arise as a result of the untreated AVSD are usually high pulmonary pressure (pulmonary hypertension), which, as a physiological counter-reaction, leads to a thickening of the muscular middle wall (media) of the pulmonary arteries. The two effects mutually reinforce each other in a kind of vicious circle (Eisenmenger reaction). The increasing insufficiency of the heart leads to a poor prognosis if left untreated.

Open heart surgery can very well improve the long-term prognosis. The most important steps during the operation are the reconstruction of the two atrioventricular heart valves, the mitral valve in the left and the tricuspid valve in the right heart, and the removal of the septal defects by applying artificial patches. In addition to the classic surgical risks associated with open heart surgery on a baby or toddler, there is a specific risk in a disruption of the electrical excitation system.

The AV node, which collects the electrical impulses from the clock (sinus node) and transmits them to the downstream systems with a slight delay, is usually particularly affected. If the problem cannot be solved with medication, an artificial pacemaker must be implanted.

When should you go to the doctor?

A genetically determined atrioventricular septal defect (AVSD) becomes symptomatic in the newborn within the first few days. There is no need to ask when medical help must be sought. The severity of the heart malformation can be determined by means of echocardiography and confirmed and supplemented by ECG findings. With a fully developed AVSD, all four heart chambers are connected to one another and, if left untreated, the prognosis for the newborn is extremely unfavorable.

During a surgical procedure in a special clinic, the connections between the two chambers are closed and the two inoperative heart valves between the left atrium and left chamber (mitral valve) and between the right atrium and right chamber (tricuspid valve) are usually replaced. Such an intervention improves the survival prognosis for the newborns dramatically.

For those affected, a nearly normal life is usually possible after a successful operation if the reconstructive operation is carried out early enough and no irreversible damage to the lungs or heart muscle has yet formed.

After reaching adulthood, the intervals for medical check-ups can definitely be extended if the symptoms remain free. However, those affected should watch out for specific symptoms that could indicate a new problem and that must be clarified immediately by a cardiologist or an experienced family doctor.

Treatment & Therapy

If the heart defect is not treated, only 10 percent of the affected children are still alive after six months. The patients develop pulmonary hypertension and, as a result, a so-called Eisenmenger reaction. Most atrioventricular septal defects are discovered early and are operable.

Using the heart-lung machine, the arterial and venous circulation are separated from each other again. In the first six months after the operation, medical endocarditis prophylaxis is carried out in accordance with current medical guidelines. After the operation, regular check-ups must also be carried out. The long-term prognosis of the operated children is very good. A second operation is rarely required.

Outlook & forecast

The prognosis of an atrioventricular septal defect is poor. If healing takes place, there is an increased risk of suffering a secondary disease. Over 35% of patients develop other heart diseases that are lifelong and no longer curable. Down syndrome is diagnosed as the underlying disease in the majority of patients. About ΒΌ of those with atrioventricular septal defect are among them.

The diagnosis and the start of treatment are essential for the prognosis. The children are born with the defect and need therapy as soon as possible. Without medical care, there is a risk of premature death within the first few weeks or months of life.

Statistics show that untreated children have an approximately 90% chance of dying within the first 6 months of life. The shortness of breath and non-functional heart activity put such a strain on the organism that there are hardly any chances of survival without intensive medical therapy. Multiple organ failure or death from suffocation would be the devastating consequences.

In professional medical care, the heart’s activity is stabilized with a heart-lung machine. This improves the prospect of survival considerably. As soon as the child is in a stable state of health, an operation is carried out. This significantly increases the likelihood of survival and enables the patient to have sufficient independent cardiac activity.

Prevention

Since the exact causes of the atrioventricular septal defect are unknown, the disease cannot be prevented. If a child with the heart defect has already been born in a family, there is a 2.5 percent risk of recurrence if another child is born. Especially in families with such an increased risk of the disease, prenatal diagnostics can help to identify the heart defect at an early stage. The earlier the diagnosis is made, the better the prognosis.

Aftercare

With this disease, in most cases there are no or only very few options and measures for follow-up care available to those affected. The person concerned is first of all dependent on a comprehensive and, above all, early diagnosis in order to permanently alleviate the symptoms and to recognize the heart defect at an early stage. Since it is also a congenital disease, it cannot be treated causally, but only purely symptomatically.

Complete healing cannot occur, and self-healing cannot occur either. In most cases, this defect is relieved by surgery. The further course depends very much on the time of diagnosis, so that no general prediction can be made. After such an operation, the person concerned should definitely rest and take care of his body.

You should refrain from strenuous or stressful activities in order not to put unnecessary strain on the heart. Regular checks and examinations are also necessary after the procedure. If the procedure is successful, there will be no reduced life expectancy for those affected. However, most of those affected also have other heart problems that also need treatment.

You can do that yourself

The atrioventricular septal defect as a congenital heart disease represents a daily challenge for affected families. In particular, when the risk of the disease is increased, prenatal diagnostics are indispensable in order to detect the heart defect at an early stage. However, it is often possible for those affected to lead an almost normal life.

However, regular intervals for medical follow-up checks and strict adherence to medication plans are advisable. Other important aspects are abstaining from nicotine and leading a healthy lifestyle. To avoid psychogenic stress, emotional stress and social law issues, it is advisable to seek out self-help groups and suitable therapists. Problems such as: special educational needs, sporting restrictions, school disadvantage compensation or relaxation procedures can be clarified.

Mental and physical agility promote self-confidence and have stabilizing properties. Those affected are therefore encouraged to take an active part in public life on their own initiative. Exercising hobbies here serves as a sensible introduction and motivational aid. Well-organized trips and excursions make a significant contribution to a healthy quality of life; renouncing it has a negative effect on the mental state.

Support from family and friends as a strong social network can also increase your own well-being and reduce tension. Further information on the subject of heart disease is also available from the Deutsche Herzstiftung eV and the Federal Association of Children with Heart Disease.

Atrioventricular Septal Defect