All congenital heart malformations that result in only one of the two heart chambers being functional are summarized under the term single ventricle. Such malformations are always complex and associated with other heart defects. The non-development of the left or right ventricle is always accompanied by atresia or total dysfunction or displacement of the two atrioventricular valves and/or the two semilunar valves, the outlet valves of the pulmonary and systemic circulation.
What are single ventricles?
The term single ventricle already indicates that these are cardiac malformations that result in either the right or the left chamber of the heart being functional. In people with healthy hearts, the left ventricle pumps oxygen-rich blood, which comes from the pulmonary circulation, into the aorta and thus supplies all organs and tissues of the body with oxygen-rich blood. For hypersplenism definitions, please visit definitionexplorer.com.
The right ventricle collects the venous blood from the systemic circulation, which first flows into the right atrium via the superior and inferior vena cava and pumps it into the pulmonary circulation. The single ventricle, also known as the one-chamber heart, has several different manifestations. If the right ventricle is hypoplastic and the left ventricle is functional at the same time, both atrioventricular valves can, for example, be designed as inlet valves for the left ventricle.
The main artery (aorta) and the pulmonary artery (pulmonary artery) can both originate in the left ventricle. The situation is analogous when the right ventricle is functional and the left ventricle is hypoplastic. Both AV valves or a common AV valve drain into the right ventricle and both outlets, the trunk of the pulmonary arteries and the aorta, exit from the right ventricle.
Causes
Inadequate supply to the corresponding ventricle is thought to be the main cause of hypoplastic development of the left or right ventricle. An insufficient blood supply can occur, for example, if there is atresia, i.e. a complete closure, of one of the two AV valves, the tricuspid valve (right heart) or the mitral valve (left heart).
Because the arterial outlets, the aorta in the left ventricle and the pulmonary artery in the right ventricle, cannot form in the underdeveloped right or left ventricle, obstructions and other accompanying malformations occur. The causes of the development of AV valve atresia are not sufficiently known.
It has not yet been possible to clarify whether, for example, drug or alcohol abuse can play a role during the early pregnancy phase. It is very likely that a genetic disposition plays the main role in the development of tricuspid valve or mitral valve atresia, which then result in further malformations such as transposition of the large arteries and other anomalies in and on the heart.
Symptoms, Ailments & Signs
The two blood circuits, the pulmonary circuit and the systemic circuit, are short-circuited before birth via the ductus arteriosus, a planned connection between the aorta and the pulmonary trunk, the pulmonary trunk artery, because the pulmonary circuit does not yet play a role in the unborn child. Only after birth does the ductus arteriosus gradually close within about five days.
The natural “short circuit” between the two circuits before birth is the reason that a serious heart defect such as a single-chamber heart often goes undetected during pregnancy. Typical signs of cyanosis (blue addiction) and cardiac insufficiency with limited resilience, poor drinking behavior and groaning with an increased respiratory rate only appear within a few days after birth.
Diagnosis & course of disease
Easy-to-use, non-invasive diagnostic measures consist of auscultating the heart sounds with a stethoscope, feeling the pulse and the electrocardiogram (ECG). Non-invasive sonography ( ultrasound examination ) is also considered to be a diagnostic tool with high informative value. If there is any diagnostic doubt, the two imaging methods cardio CT and cardio MRI are available.
If left untreated, the course of the disease varies from person to person. It depends on the extent to which the functioning chamber of the heart can supply both circuits with blood, which in turn depends on the arrangement of the vessels. In many cases, a foreseeable serious course can be stabilized by several surgical interventions, so that a perspective on life is created.
Complications
In this disease, those affected primarily suffer from a very serious heart defect. In the worst case, this can result in the death of the person concerned. Death very often occurs in the form of sudden cardiac death. The disease also causes difficult breathing and breathing difficulties.
The skin can turn blue due to the lack of oxygen. Furthermore, the internal organs and the brain are undersupplied, so that they can be irreversibly damaged. Mental retardation can also occur due to brain damage. Those affected sometimes suffer from heart failure and also from permanent tiredness and exhaustion.
This often cannot be compensated for with the help of sleep. Poor drinking behavior also sets in, as those affected suffer from swallowing difficulties. In general, the quality of life of the patient is significantly reduced and restricted due to the illness.
The disease is treated with the help of a surgical procedure. Complications usually do not arise. The symptoms are completely resolved by the procedure, so that the person concerned can lead an ordinary life. As a rule, the life expectancy of the patient then remains unchanged.
When should you go to the doctor?
In the case of a single ventricle, treatment by a doctor must be carried out in any case. Since this disease is a congenital heart defect, it can lead to serious complications or, in the worst case, death of the affected person if left untreated. Self-healing cannot occur with this disease.
If left untreated, the patient’s life expectancy is significantly reduced due to single ventricle. A doctor should be consulted if the child suffers from blue discoloration of the skin and lips and thus from shortness of breath. In most cases, those affected are tired and lethargic and do not actively participate in everyday life. The resilience of those affected is also significantly reduced, with the children drinking only little. If these symptoms occur, a doctor must be consulted immediately.
As a rule, single ventricle can be recognized and treated by a general practitioner or a pediatrician. An operation may also be necessary. In most cases, however, the disease can be treated well. Since the disease can also lead to psychological upsets in the parents and relatives, they should undergo psychological counseling.
Treatment & Therapy
The therapeutic options for treating the single-chamber heart mostly relate to surgical interventions on the heart that affect atresia of the heart valves and to establish connections between the pulmonary and systemic circulation. These are intended to ensure that the functional ventricle can initially serve both blood circuits.
Newborns are often given prostaglandin E1 as a continuous infusion because it keeps the ductus arteriosus open after birth. The same applies to the foramen ovale, a small opening between the two atria. In some cases, a special shunt between the aorta and the pulmonary artery is also necessary to stabilize the circulation.
In addition, a so-called pulmonary artery banding, an artificial narrowing of the main pulmonary arteries, is important in order to keep the arterial pressure in the pulmonary arteries low. In a subsequent Fontan operation, the two circuits are separated so that venous blood from the systemic circuit is transported into the lungs solely by the residual venous pressure via the pulmonary arteries, without a pumping heart intervening.
The functional left or right ventricle then exclusively supplies the arterial side of the systemic circulation, while the deoxygenated blood from the venous side of the systemic circulation is guided directly into the arterial part of the pulmonary circulation, bypassing the heart.
Prevention
There are no known preventive measures to prevent a single ventricle. The heart is formed very early in the embryonic stage, so that it starts working as early as the third week of pregnancy. There is no knowledge as to whether drug and alcohol consumption or nicotine abuse can cause or promote the malformation of the heart. It is very likely that genetic predispositions and gene mutations play the most important role in causing the disease.
Aftercare
Follow-up care for a single ventricle depends on the severity of the condition and the type of treatment. After an operation, the child needs comprehensive follow-up care. Depending on whether a Fontan operation, a Norwood operation or another procedure such as a complete heart transplant is performed, the follow-up care will be decided on this basis.
Since the life expectancy of children with single ventricle is relatively low, parents need comprehensive aftercare in the form of psychological care. Depending on the course, it can be supportive measures to cope with stress or trauma therapy that helps the parents back to life after the death of the child. Which aftercare measures are necessary for a single ventricle depends entirely on the course of the condition.
The cardiologist, the pediatrician or the chief physician in the clinic takes care of the follow-up care. In addition, psychologists and other doctors and therapists are involved in the aftercare. If the operation is successful, the child must then have regular cardiological follow-up care. The heart must be examined extensively so that any complications can be detected early. Follow-up care for the single ventricle can significantly improve the life expectancy of the child.
You can do that yourself
Single Ventricle can be treated quite well with medical attention and consistent use of the prescribed medication. However, it can lead to an impairment of the quality of life and negative moods in everyday life. Psychological counseling is therefore recommended for the affected families. Among other things, the parents of sick children should inform themselves about the reduced life expectancy of the disease.
They also learn about signs of shortness of breath. In everyday life, patients should not be exposed to excessive stress. It is also important to ensure that they drink enough fluids. A blue discoloration of the skin and lips indicates insufficient oxygen supply. Careful monitoring is required to ensure that patients participate at least partially in normal activities. In emergencies, a doctor’s visit is required.
Basically, there are no preventive measures to prevent the disease in the self-help tips. Malformations of the heart can occur even in the early embryonic stage. There is still no clear evidence as to whether the disease is favored by the consumption of drugs, alcohol or nicotine.
