Patent fossa ovalis

Introduction In the human fetal period, a small hole in the left and right atrial septum, that is, the blood in the left and right atrium of the fetal period is connected. Later, after the lung cycle was completed, the hole was closed. This is a trace of the legacy of human history. The foramen ovale is usually closed in the first year after birth. If the foramen ovale is larger than 3 years old, the patent foramen ovale (PFO) is not closed. About 20% to 25% of the eggs in adults The round hole is not completely closed. The foramen ovale is a life channel necessary for fetal development. The umbilical vein blood from the mother enters the left heart chamber of the fetus through this channel, and then distributes it to the whole body to provide oxygen and nutrients needed for fetal development. When the child is born, with the first cry, the left atrial pressure rises, the oval fossa is pressed against the edge of the fossa ovalis to form a functional closure, and the anatomical complete closure is generally 5-7 months after birth. . Therefore, it is possible to remain open within one year of age, there may be a small amount of shunt, and even 5% -10% of the human foramen ovale remain open and not closed for a lifetime, but has no effect on the hemodynamics of the heart. Therefore, the patent foramen ovale in infancy is a normal physiological phenomenon, not a congenital heart disease, and generally does not require surgery. However, if the defect in the center of the interatrial septum is larger than 8-10 mm and the flow rate is large, it is called a central atrial septal defect and requires surgical repair. The timing of surgery should be completed when the child is 2 to 4 years old.

Cause

If a pregnant woman is infected with a virus during pregnancy, has been exposed to radiation or has eaten some drugs that impair the development of the fetus, it may increase the chance that the foramen ovale will not close. The patent foramen ovale is closely related to diseases such as unexplained cerebral embolism, diving decompression sickness, and migraine. Therefore, some scholars believe that patients with a history of unexplained cerebral embolism, divers, astronauts, and refractory migraine have eggs. Repair should be performed when the round hole is not closed.

The formation of the foramen ovale occurs when the embryo develops to the 6th and 7th week, and the atrial septum is issued with 2 septa. The first septum is the primary septum or the first septum, and the posterior septum is the secondary septum or second. Separate, the primary septum from the atrial center of the midline back side wall is a half-moon shape, the growth of the atrioventricular tube and the endocardial pad fusion, and the end of the atrioventricular septum leaving a small hole, called the primary hole. Before the primary hole is not closed, the primary end of the proximal end forms a hole, called the secondary hole, which is the normal passage of blood during the fetal period. At the same time, on the right side of the first compartment, a scorpion-shaped septum grows from the atrial wall, which is called the secondary septum or the second septum. The septum does not continue to grow and separates the atrium and stops midway. In the fossa ovalis, the primary septum and the secondary septum at the fossa ovalis do not adhere to the fusion to leave a small fissure called the foramen ovale.

an examination

Related inspection

M-mode echocardiography (ME) two-dimensional echocardiography Doppler echocardiography cardiac vascular ultrasound

The closed oval pore is a type of atrial septal defect, but it is relatively lighter than other atrial septal defects. Ultrasound has the advantages of convenient, non-invasive, high accuracy and repeatable examination for the diagnosis of neonatal patent foramen ovale, which can provide accurate basis for clinical diagnosis and treatment.

The patent foramen ovale is asymptomatic, it is difficult to hear the noise, and the electrocardiogram and chest X-ray film are normal. Therefore, it is not easy to find and is not valued by people. The diagnosis of patent foramen ovale is mainly based on echocardiography to confirm the diagnosis. Posterior foramen ovale showed no continuous interruption of interatrial septum under transthoracic ultrasound (TTE) or transesophageal ultrasound (TEE). There were left and right atrial septum left to right or right in color Doppler imaging. A small shunt on the left.

1, right heart catheterization

In the past, the diagnosis of patent foramen ovale mainly relied on autopsy and right heart catheterization. Right heart catheterization can directly enter the left atrium from the right atrium through the patent foramen ovale, confirming the presence of patent foramen ovale. Color Doppler ultrasonography is currently used to improve the accuracy of the diagnosis.

2, echocardiography

Transthoracic ultrasound and transesophageal ultrasound can be found in left-to-right shunt or right-to-left shunt for patent foramen ovale. Ultrasound contrast echocardiography can detect potential patent foramen ovale. Valsalva action or cough test can make patent foramen ovale The detection rate is as high as 60% to 78%. For patients with unexplained transient brain insufficiency (TIA) or unexplained cerebral embolism, echocardiography should be used to find patent foramen ovale. Valsalva action or cough test can increase the right atrial pressure transiently. At this time, the injection of microbubbles can improve the detection rate of patent foramen ovale. The rate of transesophageal ultrasound for the patent foramen ovale was 3 times that of transthoracic ultrasound.

Differential diagnosis

Generally, children with congenital heart disease have two major symptoms: one is purpura. The children's lips or nails have a cyanosis. As the age increases, purpura will increase, and parents or doctors can easily find or diagnose it. There is also a class of children born without bruising, but these children have some other symptoms, such as feeding difficulties, easy to sweat, the heart is growing with age, the thorax will bulge. If parents are careful, holding their children in their arms may also hear snoring noises. Another important symptom of this type of child is that they are prone to colds or pneumonia. The symptoms of various types of congenital heart disease vary in severity. When the following symptoms occur in children, parents or doctors should think about congenital heart disease:

1. Sustained heart and respiratory dysfunction after birth;

2. irritability, high-pitched crying, sucking weakness when feeding, difficulty in feeding, weight does not increase;

3. Continued bruising or repeated confusion, easy to asthma after crying or activity, and the lips are blue and purple;

4. Repeated "pneumonia" in the lungs;

5. Older children will complain of chest tightness, pain in the precordial area, and palpitation, especially after the activity. These symptoms are more obvious;

6. Some cyanotic congenital heart disease children may also have clubbing toes (ie, soft tissue hyperplasia at the end of the hand or toe, which is bulging), and the longitudinal and transverse diameters of the nails are excessively curved, such as parrots, which are due to chronic deficiency. Caused by oxygen;

7. Cyanotic congenital heart disease often has several special postures: the legs are not straight when holding in infants and young children, and they are bent in the abdomen of adults. When sitting, they like to lift their feet to the stool surface. When standing, the lower limbs remain curved. Pose. When the older child walks, he walks down for a while and knees down to rest on the chest for a while, medically known as the "" phenomenon. These postures are to improve the lack of oxygen;

8. Congenital heart disease is prone to repeated respiratory infections.

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