Another important reason is that the physical examination items in this era are too simple. Among the physical examinations that children undergo at school every year in accordance with national requirements, the most common heart examinations are an electrocardiogram and a chest X-ray. Some even cannot arrange an electrocardiogram.
.In the absence of instruments for testing, let the doctor use a simple stethoscope to try to hear the subtle problems in the heart: Well, the doctor who can do this is a god.
Besides, the number of heart diseases that can be determined solely by electrocardiogram and chest X-ray is very limited.
To give the simplest example, a sixteen-year-old girl in bed No. 12 suffered from atrial septal defect.
This disease can be regarded as a big or small disease. What is very interesting is that it is a congenital disease, which means that it is born with abnormalities starting from embryonic development. Next, there are many cases of this congenital disease that are strange.
It was diagnosed in adulthood, and it has become a heart malformation disease that is common in adults. What does it mean? It means that it is difficult to find it without accurate medical detection equipment. To be precise, a cardiac color ultrasound is required.
Why can't this disease be detected in time by electrocardiogram and chest X-ray? Let's talk about its pathogenesis.
The atrial septum is similar to a wall. As you can tell from the name, it is located between the left atrium and the right atrium. The wall's job is to block. The atrial septum blocks the blood from the left atrium and the right atrium, allowing the blood from these two atria to flow.
Not connected.
The name of atrial septal defect is more vivid, describing the characteristics of this disease: the wall is defective. The defective wall is either a hole, one, two or three, or it is directly missing, and the entire wall is damaged.
You are missing a piece.
Since the cause of this disease is congenital, we must start with how the atrial septum grows.
In the process of building the wall of the interatrial septum, you need to build an initial wall first, which is called the primary septum. If an abnormal block occurs during the completion of the primary septum, the gap left is called the primary hole. The primary hole
If it cannot be filled, it is called atrial septal defect of the foramen primum. This is one of the diseases of atrial septal defect.
According to the above statement, the primary diaphragm needs to be built completely, so that the disease will not occur. The problem is that the process of building the interatrial partition wall is built during the fetal period when the baby is in the mother's womb.
There is a big problem with building walls during the fetal period: During the fetal period, the baby absorbs oxygen and other nutrients through the placenta, not through its own breathing and pulmonary circulation. Therefore, the right atrium and left atrium of the fetus need to be connected to allow the placenta to be rich in blood, oxygen and other nutrients.
It can flow directly into the left atrium and left ventricle of the baby, and then go to the entire systemic circulation to nourish the whole body.
In this way, the entire wall cannot be blocked by building a room partition wall. What should we do?
The original wall had to degenerate and create a hole. This hole grew from behind, so it is called a secondary hole.
The secundum hole is useful for the baby during the fetal period, but it is useless after the child is born, and if it remains there, problems will occur. The human body is prepared to block the hole in advance, so another wall grows on the original wall called
Secondary diaphragm, this secondary diaphragm is equivalent to a patch that blocks the hole. At this time, the secundum pore has another name, which many mothers have heard: it is the famous foramen ovale.
To sum up, in order to maintain communication between the left atrium and the right atrium during the fetal period, the secondary diaphragm and the primary diaphragm are not fused. In this way, blood can enter the foramen ovale of the right atrium and then pass through the gap between the primary diaphragm and the secondary diaphragm.