Congenital heart disease, or congenital heart disease, is an abnormality of the cardiovascular system caused by abnormal development during fetal life. The incidence is about 6 to 9 per 1,000. Children with congenital heart disease are often less developed than their peers, weaker and more susceptible to colds and pneumonia.
The normal heart is a muscular pump that pumps oxygenated blood from the left ventricle to the aorta and then throughout the body to meet the body’s growth and developmental needs. It also pumps venous blood, which has been consumed with oxygen and nutrients and contains the products of tissue metabolism, into the right atrium, right ventricle, and then into the pulmonary artery and lungs, where the blood receives oxygen and then returns to the left ventricle through the pulmonary veins and left atrium.
The main structures of the heart and great vessels are the right atrium, the right ventricle, the pulmonary artery, the left atrium, the right ventricle, the aorta, and the atrioventricular valve between the atrium and the ventricle, which is called the tricuspid valve on the right and the mitral valve on the left. The valves between the aorta and the left ventricle and between the pulmonary artery and the right ventricle are all three leaflets, called semilunar valves, or aortic valves, and pulmonary valves. There is a thin muscular septum between the right and left atria and a thick muscular septum between the right and left ventricles, called the atrial septum and ventricular septum, respectively.
Clinically, they are often divided into cyanotic and non-cyanotic types according to the presence or absence of cyanosis. Pulmonary vascular normal precordial disease includes simple right-sided heart without other malformations, right aortic arch, vagal subclavian artery and aortic constriction. Pulmonary oligemia is commonly seen in pulmonary stenosis and tetralogy of Fallot. Pulmonary congestion is seen in left-to-right shunt congenital heart disease, where atrial septal defect, ventricular septal defect, and patent ductus arteriosus are common.
Common congenital heart diseases
Atrial septal defect
There are primary and secondary foramina, with the latter being more common. In general, the pressure in the left atrium is higher than that in the right atrium, so the atrial defect is a left-to-right shunt, which increases the blood flow in the right atrium, right ventricle and pulmonary artery, resulting in pulmonary congestion and enlargement of the right atrium and ventricle. Pulmonary artery pressure is usually normal or mildly elevated. Significant pulmonary hypertension occurs most often in adults and can result in bidirectional or right-to-left shunts. The clinical picture is one of late-onset cyanosis.
Ventricular septal defect
Ventricular defects are divided into membranous and muscular defects, with membranous defects being the most common. If the defect is small with little shunt flow and little cardiopulmonary change or only mild enlargement of the left ventricle, the diagnosis should be confirmed with clinical signs. Large defects with moderate to large left-to-right shunts can cause enlargement of the left and right ventricles, mild enlargement of the left atrium, pulmonary congestion, and normal reduction of the aortic node. Due to the large amount of shunt pulmonary circulatory resistance increases, the right ventricular load increases, causing pulmonary hypertension then there is a bidirectional or right-to-left shunt, clinical appearance of late onset cyanosis.
Unclosed arterial duct
The unclosed ductus arteriosus constitutes an abnormal channel between the aorta and the pulmonary artery, and blood is continuously shunted from the aorta to the pulmonary artery via the unclosed ductus arteriosus because the pressure in the aorta is higher than that in the pulmonary artery. This reduces the blood flow in the body circulation and increases the blood flow in the pulmonary circulation and to the left heart, causing pulmonary artery dilation, pulmonary congestion and enlargement of the left atrium, left ventricle and right ventricle, and widening of the aortic node. When pulmonary hypertension is present, right ventricular enlargement is more pronounced.
Causes of abnormal fetal heart development.
1. Factors of the fetal developmental environment are the most important viral infections in utero, among which rubella virus infection is the most prominent, followed by coxsackie virus infection. It is well recognized that if a mother has rubella in the first trimester, she will give birth to a baby with a higher prevalence of precordial disease; among them, arteriovenous ductus arteriosus and pulmonary artery stenosis are more common. Other diseases such as amniotic membrane, fetal pressure, early pregnancy preterm abortion, maternal malnutrition, diabetes, phenylketonuria, hypercalcemia, radiation and cytotoxic drugs in early pregnancy, etc., all have the potential to make the fetus develop precocious heart disease.
The former is related to the fact that the ventricular septum does not have enough time to complete development before birth, and the latter is related to the fact that the vasoconstriction response of preterm infants is not strong enough after birth. The latter is related to the fact that the vasoconstriction response of preterm infants is not strong enough after birth.
3, plateau environment plateau area arteriovenous ductus arteriosus and atrial septal defect more. The prevalence of this disease is much higher in the Qinghai plateau than in the plains. The low partial pressure of oxygen in the plateau is the main factor.
4, genetic factors in a family, siblings at the same time or parents and children at the same time suffering from precardiac disease, as well as a number of chromosomal abnormalities in the genetic disease at the same time there are cases of cardiovascular malformations, indicating the existence of genetic factors of the disease. Genetic studies have concluded that most precardiac diseases are formed by the interaction of multiple genes and environmental factors.
5, other factors, older mothers (more than 35 years old) have a greater risk of giving birth to babies with precocious heart disease. There is a significant gender difference in the incidence of some precocious diseases.
Risk factors for congenital heart disease.
1. A family history of congenital heart disease. It is not uncommon for siblings to have congenital heart disease at the same time, and for parents and children to have congenital heart disease at the same time, and the nature of the disease is very similar. If the first child born to a mother with congenital heart disease, the likelihood of the second child having the disease is about 2%; if two consecutive children are born with congenital heart disease, the number of new children with congenital heart disease may increase to 10%. If the mother suffers from precocious heart disease, the risk of the second generation suffering from precocious disease is 10%.
2, pregnant women with untreated and uncontrolled diabetes mellitus, the risk of congenital heart disease in the fetus is 2%.
3, pregnant women exposed to teratogenic drugs in early pregnancy, such as lithium, phenytoin sodium or steroids, etc., can lead to a 2% prevalence of fetal congenital heart disease.
4, early pregnancy by radioactive substances such as X-rays, isotopes and other excessive exposure.
5.Viral infection. Women in the first three months of pregnancy, especially the 3 weeks-8 weeks of pregnancy, if infected with viruses, the fetus is prone to cardiovascular malformations. Among them, rubella virus is the main culprit of fetal precocious heart disease. In addition, influenza, mumps, coxsackie virus, herpes virus, etc. are often the “perpetrators” of pediatric precocious heart disease.
6, pro-marriage. Close marriage is a high risk factor for fetal malformation and the occurrence of precocious heart disease.
7, bad habits. Pregnant women are addicted to “swallowing fog” or husband smoking, wife “passive smoking” can make the fetal malformation or pediatric precocious heart disease. The incidence of pre-cardiac disease in infants, babies born to smoking mothers is two times that of non-smoking mothers. Conception after drinking” can cause chromosomal abnormalities in the fetus, and most babies born with alcoholism have cardiovascular abnormalities.
Symptoms of congenital heart disease.
Congenital heart disease is the most common cardiovascular disease in children, and is usually diagnosed before the age of 3. Congenital heart disease is mainly due to the arrest or abnormal development of fetal cardiovascular development for some reason during the early stages of fetal development, usually the first 3 months of embryonic life. The more recognized causes are viral infections such as rubella and influenza in pregnant women; hormones or other drugs that damage the fetus in pregnant women; exposure of the abdomen or pelvis to X-rays, ultrasound, radionuclides, etc.; or severe nutritional deficiencies or lack of oxygen in pregnant women. Some children have congenital heart disease in addition to multiple malformations throughout the body, which often suggests that the child has congenital heart disease due to genetic defects in the germ cells. In mild congenital heart disease, there may be no specific symptoms, normal growth and development, and only a rough and loud murmur is found in the left chest during physical examination. In children with severe congenital heart disease, obvious symptoms appear as early as the neonatal period or infancy.
The main manifestations are.
1. Cyanosis is seen at the tip of the nose, lips of the mouth, nails and conjunctiva of the skin and mucous membranes of the child. At the same time as cyanosis appears, the child’s growth is delayed, mental retardation, respiratory distress may occur when feeding or crying, and in severe cases, loss of consciousness and convulsions. Children who can walk often crouch down automatically due to the feeling of cerebral hypoxia.
2. The symptoms of heart failure are breathing difficulty, shortness of breath, the child cannot lie down, coughing, tachycardia, both lungs covered with small blisters, enlarged liver, pale face, swollen lower limbs, etc. Once the above symptoms are detected, the child must be immediately sent to the hospital for resuscitation.