Congenital heart disease (CHD) is a congenital malformation of the cardiovascular system caused by abnormal development of the heart and large blood vessels during the fetal period, and is the most common heart disease in pediatrics. According to statistics, 6-7 out of every 1000 newborns have congenital heart malformation. Most children with congenital heart disease are less developed than children of the same age, weaker, more prone to recurrent colds or pneumonia, and often poorly delayed, so parents need to take extra care and patience in food, clothing, exercise and prevention of other diseases.
Due to the effects of the disease and the trauma of the surgery, the child and the parents will have a heavy psychological burden, and the child will have anxiety and fear, and the parents will have self-blame and guilt, which may also affect the growth and personality development of the child after the surgery. Therefore, targeted health education for children with precardiac disease and their parents can help the children pass through the operation and postoperative recovery period smoothly, as well as improve the quality of life of the children after the operation.
Heart and circulatory system: The normal heart is a muscular pump that pumps oxygenated blood from the left ventricle into the aorta and then through the systemic arterial system to the whole body to meet the body’s demand for the oxidative and nutrient components carried by the blood. At the same time the venous system carries venous blood from the whole body, which has been consumed of oxygen and nutrients and carries carbon dioxide and waste products generated after tissue metabolism, into the right atrium, the right ventricle, and then pumps it into the pulmonary artery and the lungs, where the blood can receive sufficient oxygen and later return to the left ventricle through the pulmonary veins and the 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 atria and the ventricles, 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, or aortic, valves and pulmonary valves. There is a thin muscular septum between the left and right atria, and a thick muscular septum between the left and right ventricles, called the atrial septum and ventricular septum, respectively.
Congenital heart disease, referred to as precordial disease, is often clinically classified into cyanotic and non-cyanotic types according to the presence or absence of cyanosis. However, from the point of view of X-ray diagnostics, the classification is generally based on whether the pulmonary vasculature is normal, congested or less blood. Pulmonary vascular normal preconditioning includes simple right-sided heart without other malformations, right aortic arch, vagal subclavian artery and aortic constriction. Pulmonary hyperaemia is commonly seen in pulmonary stenosis and tetralogy of Fallot. Pulmonary congestion, on the other hand, is seen in left-to-right shunt congenital heart disease, in which atrial septal defect, ventricular septal defect and patent ductus arteriosus are common.
1. Common congenital heart diseases.
(1) Atrial septal defect
Atrial septal defect is a common congenital heart disease, divided into primary and secondary holes, the latter is more common. Under normal circumstances the left atrial pressure is higher than the right atrium, so the atrial defect is a left-to-right shunt, which increases the blood flow to 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.
(2) Ventricular septal defect
Ventricular defects are divided into membranous and muscular defects, with membranous defects being more 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. As the resistance of pulmonary circulation rises due to large shunts, the load on the right ventricle increases, causing high pressure in the pulmonary circulation, then bidirectional or right-to-left shunts appear, and late onset cyanosis appears clinically.
(3) Unclosed ductus arteriosus
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, the right ventricle enlarges more significantly.
2. Causes of congenital heart disease.
There are many causes of malformations in fetal heart development, and the following five categories of factors are considered relevant.
(1) The most important factor of fetal development environment is the virus infection in utero, among which rubella virus infection is the most prominent, followed by coxsackie virus infection. It is well recognized that a mother who suffers from rubella in the first trimester of pregnancy has a higher prevalence of precocious heart disease in her infant; among them, arteriovenous ductus arteriosus and pulmonary artery stenosis are the most common. This is due to the fact that the development of large blood vessels in the fetal heart takes place in the second and third trimesters of pregnancy, when viral infections in utero are sufficient to affect the development of the fetal heart. Other diseases such as amniotic membrane, fetal compression, early preterm abortion, maternal malnutrition, diabetes, phenylketonuria, hypercalcemia, and the use of radiation and cytotoxic drugs in early pregnancy all have the potential to cause preterm heart disease in the fetus.
(2) Premature premature infants suffer from ventricular septal defect and arteriovenous ductus arteriosus. 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 premature infants is not strong enough after birth. The latter is related to the fact that the vasoconstriction response is not strong enough after birth. Those who weigh less than 2500g at birth are especially prone to precocious heart disease.
(3) The plateau environment has more arteriovenous ductus arteriosus and atrial septal defect in the plateau area. 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 with precardiac disease, as well as many cases of chromosomal abnormalities of genetic diseases with cardiovascular malformations, indicating the presence of genetic factors in this 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 (over 35 years old) have a higher risk of giving birth to babies with prediabetes. Some congenital heart diseases have significant differences in incidence between the sexes.
3, the 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 children born with congenital heart disease may increase to 10%. If the mother has precocious heart disease, the risk of the second generation having precocious disease is 10%.
(2) The risk of congenital heart disease in the fetus of a pregnant woman with untreated and uncontrolled diabetes mellitus is 2%, and the risk decreases if the disease is controlled and stabilized early in pregnancy.
(3) Exposure to teratogenic drugs such as lithium, phenytoin sodium or steroids in early pregnancy can lead to a 2% prevalence of fetal congenital heart disease.
(4) Excessive exposure to radioactive substances such as X-rays and isotopes in early pregnancy.
(5) Viral infections. Viral infections in the first trimester of pregnancy, especially in the third to eighth weeks of pregnancy, can predispose the fetus to cardiovascular malformations. The rubella virus is the main culprit of fetal precocious heart disease. In addition, influenza, mumps, coxsackie virus, herpes virus, etc. are also often the “perpetrators” of pediatric precocious heart disease.
(6) pro-marriage. Consanguineous 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 fetal malformations or the occurrence of 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. Couples “conceive after drinking” will cause chromosomal abnormalities in the fetus, giving birth to babies with alcoholism, most of which are accompanied by cardiovascular abnormalities.
4.Common symptoms
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 some reasons that cause the fetal cardiovascular development to stop or develop abnormally during the early stage of fetal development, usually the first 3 months of embryonic life. The most recognized causes are viral infections such as rubella and influenza; hormones or other drugs that damage the fetus; exposure of the abdomen or pelvis to X-rays, ultrasound, radionuclides, etc.; or severe nutritional deficiencies or oxygen deprivation. 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 special 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.
5. The symptoms of congenital heart disease are mainly twofold.
(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 affected child. At the same time as cyanosis appears, the child has growth retardation and mental retardation. When feeding or crying, breathing difficulties may occur, and in severe cases, there is loss of consciousness and convulsions. Children who can walk often crouch down automatically due to the sensation of cerebral hypoxia.
(2) The symptoms of heart failure are dyspnea, shortness of breath, inability of the child to lie down, coughing, tachycardia, two lungs covered with small blisters, enlarged liver, pale face, swollen lower limbs, etc. Once the above symptoms are found, the child must be immediately sent to the hospital for rescue.
6.How to diagnose
Based on the history, physical signs, chest X-ray and ECG cardiac vectorogram, the diagnosis of common precordial disease can generally be made. M-mode, cross-sectional and pulsed Doppler echocardiography, as well as computerized MRI and X-ray tomography, are currently considered to be non-invasive diagnostic methods for this disease.
(1) In the medical history, attention should be paid to the age of onset of heart disease and when the characteristic heart murmur was detected. The younger the age of onset and when the characteristic heart murmur was detected, the greater the likelihood of precordial disease. Family history, prenatal maternal health status and the condition of the child at birth are all informative for diagnosis. In addition, patients with a history of infective endocarditis should be examined for the presence of precordial disease.
(2) Hemoptysis in symptoms is often diagnostic as it reflects pulmonary congestion due to massive left-to-right shunts or left heart failure due to aortic and left heart lesions; however, it is also important to note that hemoptysis in the type of pulmonary ischemia (e.g., pulmonary orifice stenosis, tetralogy of Fallot, etc.) can also occur after the establishment of collateral circulation between the pulmonary and bronchial vessels. The age of appearance of the purple group is helpful in identifying several precordial diseases with right-to-left shunts. Cyanosis appears from an early age in tetralogy of Fallot, aortic trunk immortality, and complete macrovascular misalignment; it appears later in trisomy of Fallot and Eisenmenger’s syndrome. The occurrence of right heart failure alone without the manifestation of antecedent left heart failure is common in the category of right heart valve lesions in precardiac disease, or in those with pulmonary hypertension, which is rare in other heart diseases (except pulmonary heart disease).
(3) The most diagnostic value of the signs is the specific murmur and other heart sound changes that different categories of precardiac disease have in themselves. If this murmur is detected in early childhood, the likelihood of precordial disease is very high. Cyanosis with pestle-like fingers (toes) suggests that cyanosis has existed for many years; an enlarged heart with a localized chest bulge often suggests that the patient has had an enlarged heart since childhood, and the possibility of precordial disease is also high.
(4) Chest X-ray examination can provide information for the diagnosis and differential diagnosis of the disease by observing the congestion or ischemia of pulmonary vessels, the enlargement of the heart shadow or certain atrial enlargement, the change of the shape of the heart shadow and the special pulsation of the large blood vessels of the heart. Electrocardiogram and cardiac vectorogram can also reflect the hemodynamic changes of the disease to a certain extent, thus helping to diagnose and differentially diagnose the disease. However, it is important to note that different precordial diseases can cause similar radiographic and ECG and cardiac vectorogram changes due to similar hemodynamic changes.
Cardiac catheterization, combined with selective indicator dilution curve measurement and selective cardiovascular imaging, can provide a more direct understanding of the pathophysiological and anatomical changes in patients with this disease by measuring the pressure in each heart chamber and analyzing the oxygen content of blood specimens, injecting the indicator into each heart chamber to observe its dilution, and injecting the contrast agent to observe the flow of the contrast agent and the filling of the cardiovascular chambers. (5) M-mode echocardiography is the most effective way to diagnose and identify different types of precardiac disease.
(5) M-mode echocardiography and two-dimensional echocardiography recorded by sector scanning method can detect the anatomical and physiological activities of the heart, which is sufficient to reflect the anatomical lesions of different types of precardial disease and is a better noninvasive diagnostic method, among which pulsed Doppler plus cross-sectional echocardiography and Doppler color flow imaging have the greatest diagnostic value.
(6) Computerized magnetic resonance and X-ray tomographic imaging can be used to visualize the heart from the base to the apex of the heart in multi-level cross-sectional and sagittal views, which can help to understand the anatomical and physiological changes of complex precordial diseases, among which magnetic resonance tomographic imaging is better than X-ray tomography for soft tissue.
7.Diagnosis of common precordial diseases
Atrial septal defect
Diagnostic points.
(1) Clinical manifestations: asymptomatic in mild cases, cyanosis may appear when complicated by pulmonary hypertension
(2) Physical examination can have systolic blowing wind-like jet murmur in the 2nd intercostal space at the posterior border of the sternum, mostly without tremor, and the second heart sound can be split in the pulmonary valve area and diastolic blowing wind-like murmur can be heard.
(3) X-ray examination may show congestion in the pulmonary fields and marked prominence of the common pulmonary artery trunk arc. The lung door chorea sign, right heart and left ventricle enlargement.
(4) Electrocardiogram may have right bundle branch conduction block changes.
(5) Echocardiography and cardiac catheterization may be helpful for diagnosis.
Ventricular septal defect
Diagnostic points.
(1)Clinical manifestations: Patients with small defects are usually asymptomatic, while those with large defects accompanied by pulmonary hypertension may present with cyanosis.
(2) Physical examination reveals grade IV to V rough systolic murmur between the 3rd and 4th ribs at the left edge of the sternum, mostly accompanied by tremor. In large defects, early diastolic rumble-like murmurs can be heard in the apical region, and diastolic blowing murmurs can be heard in the pulmonary valve region in pulmonary hypertension.
(3) X-ray examination may show pulmonary stasis and enlarged left and right ventricles.
(4) Electrocardiogram may have hypertrophic changes in the left and right ventricles.
(5) Echocardiography and cardiac catheterization may be helpful for diagnosis.
Arterial catheterization
Diagnostic points.
(1) Clinical manifestations: asymptomatic in mild cases, cyanosis may appear when complicated by pulmonary hypertension.
(2) Physical examination may have a grade IV to V rough continuous machine-like murmur in the second intercostal space under the left clavicle or at the left edge of the sternum, which may be accompanied by tremor. In pulmonary hypertension, an early diastolic rumbling murmur may be heard in the apical region.
(3) X-ray examination may show pulmonary stasis, enlarged aortic node, enlarged left atrium and right ventricle.
(4) ECG may have left ventricular hypertrophy or left and right ventricular hypertrophy.
(5) Echocardiography and cardiac catheterization may be helpful for diagnosis.
Three levels of prevention
Congenital heart disease should be prevented in three levels: congenital heart disease should be prevented in three levels.
The first level of prevention is to prevent colds, less exposure to computers, better nutrition, and careful use of medication before and during early pregnancy to reduce the incidence of congenital heart disease.
The second level of prevention is to do some tests in time during the fetal period, and if the fetus is found to have congenital heart disease, abortion can be considered.
Tertiary prevention is surgery, and after contact with a specialist, different congenital heart diseases are treated with different methods. Congenital heart disease can usually be detected after the birth of the child based on the child’s symptoms.
There are six categories of high-risk pregnant women whose babies have a significantly higher incidence of congenital heart disease than babies of normal pregnant women.
First, pregnant women with high-risk or overdue pregnancies.
Second, mothers with a history of infection or medication in the first trimester; mothers with a history of long-term exposure to toxins and radiation; mothers with blood disorders, endocrinopathies, connective tissue diseases, cardiovascular diseases or genetic disorders.
Third, the mother has a history of poor childbirth with intracardiac and extracardiac malformations and a family history of heart disease. Fourth, other tests have confirmed or suspected intra- and extra-cardiac malformations or chromosomal abnormalities in the fetus. Fifth, abnormal intrauterine development, too much or too little amniotic fluid. Sixth, the fetal heart rate is too fast, too slow or rhythmically irregular.