What Is Coronary Sinus: Here's Everything You Need to Know!

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Aug 14, 2020 07:00 AM

What is the Coronary Sinus?

Photo by voxel123 on Flickr

What is the coronary sinus? It is the largest cardiac venous structure that can be found on the heart’s rear surface, precisely between the left ventricle and left atrium. Basically, it is a group of smaller veins that merge together forming the sinus.

The coronary sinus has its circumference larger than the average vein. Because of its large size, it is possible for most veins from entering the heart to deposit blood.

The function of the structure is to receive the blood originated from the myocardium as well as to give way for the movement of the blood in order to enter into the right atrium. The coronary sinus is protected by a thin semicircular endocardial fold that is called as the Thebesian valve.

The coronary sinus is an important part that can help surgeons who are performing cardiac surgery and many other heart procedures.

Take a look at the article below to know more about coronary sinus, such as the further functions and possible problems related to the coronary sinus. Check it out!

Opening of Coronary Sinus

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The coronary sinus extends into the atrium, between the lower vena cava orifice and the atrioventricular opening. The opening of the coronary sinus returns blood from the heart substance. The coronary sinus is protected by a thin semicircular endocardial fold that is called as the Thebesian valve.

Coronary Sinus Location

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The coronary sinus is situated on the diaphragmatic or hind side of the heart on the back part of the coronary sulcus.

The coronary sinus empties directly into the right atrium near the junction between the posterior interventricular sulcus and the coronary sulcus (crux cordis area), situated between the inferior vena cava and the tricuspid valve. This atrial ostium can be partly protected by a Thebesian valve, but the structure of this valve is highly variable.

The coronary sinus derives drainage from most epicardial ventricular veins, including left atrium oblique vein (including other left and right atrial veins), broad cardiac vein, left ventricle posterior vein, left marginal vein, and posterior interventricular vein. In adults, the length of the coronary sinus can range between 15 and 65 mm.

Coronary Sinus Function

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The coronary sinus has the task of draining the venous blood from much of the heart. It opens up into the right atrium between the inferior vena cava gap, the fossa ovalis, and the right atrioventricular orifice. A small, semicircular, endocardial fold, also known as the Thebesian valve, also guards the coronary sinus. 

Importance in cardiovascular diseases:

Cardioplegic transmission via the coronary sinus has been found to be safe and efficient in myocardial protection, and even superior to the conventional form of antegrade cardioplegia, especially in patients with coronary artery disease.

Importance in device delivery:

Balloon catheters should be mounted in the coronary sinus to provide medications, cardioplegia reinforcements, or contrast agents to acquire cardiac venograms. Numerous machines were often implanted in the coronary sinus as a method for structurally remodeling the mitral valve annulus (e.g., reducing valvular regurgitation).

Unroofed Coronary Sinus

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Unroofed coronary sinus (UCS) is a rare atrial septal defect (ASD), which causes irregular contact between the coronary sinus and the left atrium.

Typically it is linked with certain types of congenital heart disease, usual syndromes of heterotax. A recurring left superior vena cava (PLSVC), which is the most prominent systemic venous drainage disorder, is also associated with this.

Diagnosis of this lesion is critical for the patient's prognosis due to the effects of brain abscess or cerebral embolization, which can occur from a right-to-left shunt. But, due to non-specific clinical features, the diagnosis is often difficult.

Only after examination of pre- and post-treatment hemodynamics with both co-existing anomalies is the diagnosis with unroofed coronary sinus, and chronic left superior vena cava pursued.

Enlarged Coronary Sinus

There is a possibility where the coronary sinus will enlarge if it receives a left superior vena cava or a hepatic vein. It happens when the vein is joined by a left superior vena cava that receives blood from the inferior vena cava through the hemiazygos vein.

An enlarged coronary sinus is scientifically called as Dilated coronary sinus. It can be caused by an increased blood flow due to abnormal venous drainage in the left superior vena cava.


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