Unveiling the "small window": the mystery of patent foramen ovale in babies' hearts

Author: Zhang Xin, Chief Physician, Beijing Children's Hospital, Capital Medical University

Reviewer: Wang Fangyun, Chief Physician, Beijing Children's Hospital, Capital Medical University

1. What is patent foramen ovale?

To understand what patent foramen ovale is, we must first know what a patent foramen ovale is.

The foramen ovale is a small communication opening between the left and right atria of the heart. During the fetal period, the blood with a high oxygen content from the mother needs to pass through the foramen ovale of the fetus from the right atrium to the left atrium, and then be transported to the whole body. If the foramen ovale is too small or closes too early during this period, it will affect the growth and development of the fetus. After the newborn is born, it begins to breathe independently and oxygenate in the lungs. It no longer relies on the blood flow between the right atrium and the left atrium for oxygen supply, and the foramen ovale can close on its own. If this communication opening between the right atrium and the left atrium still exists after birth, it is called a patent foramen ovale.

Figure 1 Copyright image, no permission to reprint

Most children's foramen ovale will close before the age of 2-3, but a few will persist. Studies have shown that about 1/3 of the normal population has a patent foramen ovale before the age of 30, about 1/4 of the population has a patent foramen ovale between the ages of 30 and 80, and this proportion drops to 1/5 when they are over 80 years old. The cause of patent foramen ovale is still unclear, but it may be related to familial genetic factors.

2.What are the examination methods for patent foramen ovale?

Most cases of patent foramen ovale can be detected by transthoracic echocardiography. If the transthoracic echocardiography is suspected to be positive due to unclear images, limited window, etc., or the result is negative but the clinical suspicion of patent foramen ovale is high, further ultrasound angiography or transesophageal echocardiography can be performed.

Figure 2 Copyright image, no permission to reprint

3. What should we pay attention to if a child has a patent foramen ovale?

Most children with patent foramen ovale have no symptoms, and their growth and development will not be affected. A small number of children will have neurological symptoms such as dizziness, headache, blacking out, and fainting. This is because emboli such as thrombi from the venous system pass through the foramen ovale into the left heart system, embolize the cerebral blood vessels, and cause ischemic stroke. There are also some rare reports of vascular embolism in other organs, such as coronary artery embolism, renal artery embolism, etc., which manifest as sudden myocardial infarction, renal infarction, or corresponding manifestations of embolism in other parts. If the above symptoms occur, it is recommended to visit a cardiologist.

Figure 3 Copyright image, no permission to reprint

4. How to treat patent foramen ovale?

Patent foramen ovale without symptoms does not require special treatment. If ischemic stroke or other embolic manifestations occur, you can consult a cardiologist to choose an appropriate treatment method. If conservative treatment is used, drugs to prevent thrombosis can be used under the guidance of a doctor. If surgical treatment is used, minimally invasive foramen ovale closure surgery can be selected.