The coronary sinus is the most sizeable venous structure in the heart. It returns the bulk of the left ventricle’s blood flow to the right atrium. It is the most sizeable venous structure in the heart. It produces the size of the left ventricle’s blood flow to the right atrium. It returns the bulk of the left ventricle’s blood flow to the right atrium.
Location of coronary sinus
This sinus is situated in the posterior section of the coronary sulcus. It is connected to the coronary artery. It is on the diaphragmatic or backside of the heart.
The coronary sinus drains into the right atrium. It is near the intersection of the posterior interventricular sulcus. And the coronary sulcus is located between the inferior vena cava and the tricuspid valve. This atrial ostium can be covered by a Thebesian valve, though its anatomy varies.
Most epicardial ventricular veins flow into the coronary sinus. It includes the left atrial oblique vein and other veins. It may be anywhere between 15 and 65 mm long in adults.
It is the longest and largest coronary vein. It measures around three to five centimeters in length and one centimeter in breadth. It develops between the left atrium and the left ventricle on the heart’s posterior wall.
It then continues along the left rear atrioventricular groove. It continues until emptying into the right atrium’s posteroinferior aspect. Medial to the inferior vena cava’s entry and superior to the tricuspid valve’s septal.
Many venous tributaries combine to form the cardiac sinus. The great cardiac vein’s confluence and the left atrium’s oblique vein mark the start of the coronary sinus.
The left ventricle’s posterior veins, the medium, and the small cardiac vein drain into the it. It happens immediately before reaching the right atrium.
In summary, it is fed by the following tributaries:
- The left atrium’s oblique vein
- A tiny vein in the heart
- The left ventricle’s posterior vein
- A large vein in the heart
- The vein that runs through the middle of the heart
The coronary sinus’s tributaries may be diverse. Also, to the regular branches, It may receive the anterior cardiac veins. It is done roughly in 33% of instances and the left marginal vein on rare occasions.
It might be destroyed or non-existent at times. The Marshall oblique vein connects the cardiac veins to the superior vena cava. A left-to-right shunt may occur when the coronary sinus drains into the left atrium.
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When a surgeon does heart surgery, they may use a technique known as cardioplegia. During cardiac surgical surgery, the heart is stopped. Cardioplegia delivered via the coronary sinus is efficacious and safe for myocardial protection.
It has even been discovered to be a better form of cardioplegia than the standard approach. Especially for those undergoing heart surgery for coronary artery disease therapy.
Importance In The Treatment Of Cardiovascular Diseases:
Cardioplegia delivered via the coronary sinus is safe and effective in myocardial protection. Even outperforming typical antegrade cardioplegia patients with coronary artery disease.
Ischemic heart failure and dilated cardiomyopathy are often associated with dilatation. Increased blood flow is almost the cause of a dilated vein.
Increased blood flow in the coronary sinus is caused by larger volumes entering the heart. It happens through the venae caval from the right ventricle to the right atrium owing to a defective tricuspid valve. This prevents the sinus from draining and puts strain on the elastic walls of the sinus.
When a vein is blown beyond a certain point, it cannot return to its standard shape. It stays dilated and unable to contract as before.
The coronary sinus is involved in a variety of pathologic processes, including:
- Some arrhythmias/dysrhythmias may be ablation targeted
- In biventricular pacing, the coronary sinus is ideal for lead implantation.
- Unroofed coronary sinus is an uncommon kind of atrial septal defect. It connects to the left atrium on its route to the right atrium.
- Heterotaxy syndromes and a persistent left-sided superior vena cava are linked.
Coronary Sinus runs down the left atrium’s posterior wall and into the left atrioventricular groove. The right atrium is usually where it drains. The Thebesian valve encloses it’s ostium.
The veins causing drain into it may vary. But, they often contain the following:
- A vein in the center of the heart (posterior interventricular vein)
- Great vein of the heart
- The left ventricle’s posterior vein
- A tiny vein in the heart
- The left atrium’s oblique vein.
- The Marginal vein on the left
It’s defect is characterized by an interatrial connection. It is happened via the coronary sinus orifice and the lack of the neighboring coronary sinus and left atrial walls. A persistent left superior caval vein is often connected to the left atrial roof.
In essence, the abnormality is caused by the usual walls separating it from the left atrium. It’ opening becomes an interatrial communication in their absence.
Filigreed remains of the atrial wall may be seen between it’s mouth and the terminus of the left caval vein. It is in the left atrium in some instances of this combination.
Point of Drainage
Blood is drained from several coronary veins into it. These veins collect deoxygenated blood from various myocardial regions. The left ventricle sends deoxygenated blood to the prominent cardiac, lateral, marginal, and inferior veins.
The inferior interventricular vein, drains venous blood from the surface of the myocardium. This vein merges with the great heart vein to become the great cardiac vein.
The left atrium’s oblique vein (Marshall’s vein) transfers deoxygenated blood from the heart. Finally, blood is transported from the right atrium. A part of the right ventricle through the tiny cardiac vein. Other myocardial veins enter the heart chambers.
Surgical Points to Consider
It’s position inside the right atrium provides easy access to the myocardial capillary network. Clinicians use this access in retrograde cardioplegia, a method in which paralytic drugs are administered to the myocardium.
It happens via the coronary sinus and its tributaries during cardiac surgery. The conventional anterograde way, in which cardioplegic drugs are delivered via the coronary ossia. It is delivered into the coronary arteries, is now employed with retrograde cardioplegia.
The use of retrograde and anterograde cardioplegia increases the danger of significant arterial stenoses. It results in preventing cardioplegic medicines from reaching the myocardium with insufficient dosages.
Both techniques have improved post-operative myocardial function more than anterograde cardioplegia alone. PLSVC, in which cardioplegic drugs may enter the systemic circulation. It is one of the drawbacks of retrograde cardioplegia. It’s rupture is an uncommon but severe consequence of retrograde cardioplegia.
Coronary sinus arrhythmia is another possible disease. It happens since the sinus wall also includes cardiac muscle cells. The presence of cardiac muscle in or near the sinus transmits impulses, or pressure from a dilated coronary sinus alters the right atrium’s electrical pathways.
The most typical treatment is ablation therapy. It involves searing the regions that produce action potentials outside the sinoatrial node.
You may gain the architecture of the coronary arteries and veins in great detail. Knowing the structure and abnormalities of the coronary venous system might help design operations. Coronary venous anomalies produce right to left shunts with a risk of stroke and arrhythmias may be detected with a CT scan of the coronary venous architecture.