What is congenital heart disease
Congenital heart disease is a cardiovascular malformation caused by abnormal development of the heart vessels during fetal life, and is the most common reproductive defect type of disease in children. Its incidence is about 0.8% of births, and 60% of them die at the age of <1 year. A heart with local anatomical abnormalities caused by disorders in the formation of the heart and large blood vessels during embryonic development (within the first 2-3 months of pregnancy) or failure to close channels that should close automatically after birth (which is normal in the fetus) is called congenital heart disease. Except for small ventricular septal defects that have a chance to heal spontaneously before the age of 5 years, the vast majority require surgical treatment. The main clinical manifestations are cardiac insufficiency, cyanosis and dysplasia.
Classification
There are various ways to classify congenital heart disease. Briefly, congenital heart disease is divided into three groups according to hemodynamic changes.
1.No shunt type That is, there are no abnormal pathways and shunts between the left and right sides of the heart or between the arteries and veins. It includes aortic constriction, pulmonary valve stenosis, aortic stenosis as well as pulmonary valve stenosis, simple pulmonary artery dilatation, primary pulmonary hypertension, etc.
2. Left-to-right shunt type (latent cyanotic type) This type has abnormal pathways between the circulatory pathways of blood flow between the left and right sides of the heart. In the early stage, because the pressure of the left side of the body circulation of the heart is greater than the pressure of the right side of the pulmonary circulation, the blood flow normally shunts from the left to the right without bruising. When the pressure in the pulmonary artery or the right ventricle increases and exceeds the pressure in the left side of the heart due to crying, breath-holding or any pathological condition, the blood can be shunted from the right to the left and temporary cyanosis can occur. For example, atrial septal defect, ventricular septal defect, patent ductus arteriosus, main pulmonary artery septal defect, and aortic sinus aneurysm breaking into the right heart or pulmonary artery.
3. Right-to-left shunt type (cyanotic type) The malformations included in this group also constitute abnormal traffic within the cardiovascular cavity on the left and right sides. The venous blood in the right cardiovascular cavity flows into the left cardiovascular cavity through the abnormal traffic, and a large amount of venous blood is injected into the body circulation, so persistent cyanosis may occur. This can lead to persistent cyanosis, such as tetralogy of Fallot, triad of Fallot, double outlet of the right ventricle, complete transposition of the great arteries, and permanent arterial trunk.
Etiology and pathogenesis
Heart disease is the result of a complex interplay of genetic and environmental factors. The following factors may affect fetal development and produce congenital malformations.
1. Environmental factors of fetal development:
(1) Infections, viral or bacterial infections in the first trimester of pregnancy, especially rubella virus, followed by coxsackievirus, have a higher incidence of congenital heart disease in babies born with them.
(2) Other: such as amniotic membrane lesions, fetal pressure, early pregnancy pre-eclampsia, maternal malnutrition, diabetes mellitus, phenylketonuria, hypercalcemia, the application of radiation and cytotoxic drugs in early pregnancy, the mother is too old, etc. have the potential to cause congenital heart disease in the fetus.
2, genetic factors: congenital heart disease has a certain degree of family tendency to develop, which may be caused by parental germ cells and chromosomal aberrations. Genetic studies have concluded that most congenital heart disease is formed by the interaction of multiple genes and environmental factors.
3.Other: Some congenital heart diseases are more frequent in highland areas, and some congenital heart diseases have significant differences in incidence between male and female gender, indicating that altitude and gender of birthplace are also related to the occurrence of this disease. Among patients with congenital heart disease, those who can find out the cause are very few, but strengthening health care for pregnant women, especially actively preventing rubella, influenza and other rubella viral diseases and avoiding all factors related to the onset of the disease in early pregnancy, is of positive significance to prevent congenital heart disease.
Symptoms
1.Heart failure: Neonatal heart failure is regarded as an emergency, usually mostly due to the fact that the affected child has a more severe heart defect. Its clinical manifestations are due to congestion of the pulmonary and body circulations and a decrease in cardiac output. The child is pale, breath-holding, dyspnea and tachycardia, with a heart rate of up to 160-190 beats per minute, and blood pressure is often low. A galloping horse rhythm may be heard. The liver is large, but peripheral edema is less common.
2. Cyanosis: It arises from mixing of arterial and venous blood due to right-to-left shunt. It is most obvious in the tip of the nose, lips of the mouth, and nail beds of the fingers (toes).
Squatting: Children with cyanotic congenital heart disease, especially those with tetralogy of Fallot, often show signs of squatting after activity, which increases the vascular resistance of the body circulation and thus reduces the right-to-left shunt produced by the septal defect, and also increases venous blood flow back to the right heart, thus improving pulmonary blood flow.
4, pestle finger (toe) and erythrocytosis: cyanotic congenital heart disease is almost always accompanied by pestle finger (toe) and erythrocytosis. The mechanism of pestle finger (toe) is not clear, but erythrocytosis is a physiological response of the body to arterial hypoxia.
5, pulmonary hypertension: When patients with septal defects or unclosed ductus arteriosus present with a syndrome of severe pulmonary hypertension and cyanosis, it is called Eisenmenger’s syndrome. The clinical manifestations are cyanosis, erythrocytosis, pestle fingers (toes), signs of right heart failure, such as jugular vein anger, hepatomegaly, peripheral tissue edema, when the patient has lost the opportunity of surgery, the only thing waiting is heart and lung transplantation. Most patients die before the age of 40.
6.Developmental disorders: Children with congenital heart disease often have abnormal development, manifesting as thinness, malnutrition, delayed growth, etc.
7.Other: chest pain, syncope, sudden death.
Diagnosis
Determining whether a child has congenital heart disease can be based on medical history, symptoms, signs and some special tests to make a comprehensive judgment.
1.History
(1) Pregnancy history of the mother: any viral infection in the first 3 months of pregnancy, radiation exposure, history of medication, history of diabetes mellitus, nutritional disorders, environmental and genetic factors, etc.
(2) Common symptoms: shortness of breath, cyanosis, especially pay attention to the age and time of cyanosis, whether it is related to crying and movement, whether it is paroxysmal or continuous. Symptoms of heart failure: increased heart rate (up to 180 beats/min), shortness of breath (50 to 100 breaths/min), irritability, pauses during feeding due to dyspnea and asthma-like attacks, etc. Recurrent or persistent upper respiratory tract infections, pallor, low crying, moaning, hoarseness, etc., also suggest the possibility of congenital heart disease.
(3) Development: Children with congenital heart disease are often malnourished, with thin bodies, no weight gain, delayed growth, etc., and may have squatting.
2.Physical examination
If physical examination reveals typical organic heart murmur, low heart sound, enlarged heart, arrhythmia and large liver, further examination should be conducted to exclude congenital heart disease.
3.Special examination
(1) X-ray examination: there may be an increase or decrease in lung texture and an enlarged heart. However, normal lung texture and normal heart size do not exclude congenital heart disease.
(2) Ultrasonography: quantitative measurement of the size of the chambers and blood vessels of the heart is used to diagnose the anatomical abnormality of the heart and its severity, which is one of the most common diagnostic methods for congenital heart disease.
(3) Electrocardiography: It can reflect the position of the heart, the presence of hypertrophy in the atria and ventricles, and the condition of the cardiac conduction system.
(4) Cardiac catheterization: It is one of the important examination methods for further definite diagnosis of congenital heart disease and before deciding to operate. Through catheterization, we can understand the blood oxygen content and pressure changes in different parts of the heart chambers and large blood vessels, and clarify the presence or absence of shunts and the parts of shunts.
(5) Cardiovascular imaging: Cardiovascular imaging can be performed in patients who still cannot be diagnosed clearly through catheterization and need to consider surgical treatment. The iodine-containing contrast agent is rapidly injected into the heart or large blood vessels through the cardiac catheter under mechanical high pressure, while continuous rapid film or movie is taken to observe the shape, size and location of the atria, ventricles and large blood vessels as shown by the contrast agent, as well as the presence of abnormal channels or stenosis or atresia.
Based on the positive signs from the above history, physical examination and special examination, we can make a comprehensive analysis and judgment to clarify the diagnosis of congenital heart disease.
Treatment methods
Most congenital heart diseases are highly treatable and have a good prognosis. Timely treatment can achieve good results after surgery and will not affect the growth and development of the child, as well as the future study, work and other daily life. There are two types of treatment for congenital heart disease: surgical treatment and interventional treatment.
1.Surgical treatment is the main treatment method, which is practical for all kinds of simple congenital heart diseases (such as ventricular septal defect, atrial septal defect, arteriovenous ductus arteriosus, etc.) and complex congenital heart diseases (such as congenital heart disease with combined pulmonary hypertension, tetralogy of Fallot and other heart diseases with cyanosis phenomenon). In recent years, with the continuous improvement of surgical techniques and perioperative treatment, the safety of surgery is very high, and the mortality rate of surgery in several large cardiac centers in China is close to 1%, reaching the international advanced level.
Interventional treatment is a new treatment method developed in recent years, mainly applicable to children with unclosed arterial ducts, atrial septal defects and partial ventricular septal defects not combined with other malformations requiring surgical correction can be considered for interventional treatment. The main difference with traditional surgical treatment is that interventional treatment is narrower in scope and more expensive, but it is non-invasive, with quick recovery and no surgical scars. Surgical treatment has a wider scope of application and can cure all kinds of simple and complex congenital heart diseases, but it is traumatic and has a long recovery time, and a few patients may suffer from complications such as arrhythmia, chest and heart cavity effusion, and also leaves surgical scars that affect the aesthetics. In recent years, minimally invasive and small incision surgical treatment has been adopted, which has made up for the defects of traditional surgery to a certain extent.
The best time for treatment
The optimal time for surgery depends on a number of factors, including the complexity of the congenital malformation, the age and weight of the child, and the overall development and nutritional status of the child. Generally, for simple congenital heart, it is recommended to be 1 – 5 years old, because too young, low weight, poor general development and nutritional status will increase the risk of surgery; too old, the heart will compensate for the increase in size, and some may even have increased pulmonary artery pressure, which will also increase the difficulty of surgery and longer recovery time after surgery. For those with combined pulmonary hypertension, severe congenital malformations that affect growth and development, malformations that threaten the life of the child, or complex malformations that require staged surgery, the earlier the surgery the better, regardless of age.
In general, congenital heart disease cannot heal on its own and requires surgical or interventional treatment. However, ventricular or atrial defects with a caliber of less than 0.5 cm can be treated without treatment, as they do not adversely affect the heart function and growth of the child. However, due to the presence of heart murmur, which has certain impact on future education, employment and marriage, and the surgery is very mature nowadays, some parents still choose surgery due to these social factors. There are also some small defects, such as ventricular defects in the sub-stem area, which are less than 0.5 cm due to their proximity to the aortic valve, and they also require active surgical treatment. Surgery is recommended for children with defects larger than 0.5 cm in caliber.
Home care
Try to keep the child quiet, avoid excessive crying, and ensure sufficient sleep. Older children should have a regular life, combining movement and stillness, neither running around outside (running, jumping and strenuous sports are strictly prohibited) nor lying in bed all day, and sleep must be guaranteed at night to reduce the burden on the heart.
Children with cardiac insufficiency tend to sweat more, so they need to keep their skin clean, bathe regularly in summer, rub themselves with hot towels in winter (pay attention to keeping warm), and change their clothes and pants regularly. Feed more water to ensure adequate hydration.
Keep the stool smooth, if the stool is dry and difficult to defecate, excessive force will increase the abdominal pressure, increasing the burden on the heart, and may even have serious consequences.
Keep the air circulating in the room, and avoid staying in crowded public places to reduce the chance of respiratory tract infection. Add or remove clothes in time with the weather and pay close attention to prevent colds.