The CS lies in the sulcus between the left atrium and ventricle and is a continuation of the great cardiac vein from the valve of the great cardiac vein to the ostium of the CS as it terminates in the right atrium.
The CS begins proximally at the right atrial orifice and ends distally at the valve of Vieussen's. The CS receives blood from the ventricular veins during ventricular systole and empties into the right atrium during atrial systole.
The wall of the CS is made up of striated myocardium that is continuous with the atria, forming a myocardial sleeve around the venous system 17 Figure 2.
This sleeve does not usually extend into the ventricle myocardium. In variations, where a continuation into the ventricle is formed, however, an atrioventricular bypass tract referred to as an epicardial pathway is formed. The CS has been dissected open along its long axis, CS musculature is seen in the proximal portion of the CS up to the orifice of the vein of Marshall.
In this patient multiple posterior and posterolateral veins are also seen draining into the CS. The CS, like the rest of the cardiac venous system, contains various valves. The Thebesian valve is a crescent shaped structure often found guarding the mouth of the CS as it opens to the right atrium. The Thebesian valve is highly variable and occasionally may present an obstruction during cannulation of the CS. These venous valves are also frequently found at the entrance of the ventricular veins into the great cardiac vein.
The right ventricular venous system drains directly into the right ventricle through the Thebesian venous network. The CS ostium is 5—15 mm in diameter and is located on the posterior interatrial septum anterior to the Eustachian ridge and valve and posterior to the tricuspid annulus. The valve usually covers the superior and posterior surfaces of the ostium, but may be covered completely with formation of fenestrations. In rare instances, the valve may cover the inferior hemi-circumference.
The CS has increasingly been recognized as a vital structure for an array of clinical interventions. The CS is of interest to the electrophysiologist because it provides a useful route for mapping and ablation of left-sided accessory pathways.
Nevertheless, pathways that are located close to the mitral valve may be difficult to ablate given their significant distance from the CS. In addition, the CS is an electrophysiologically active structure. Previous studies have demonstrated the capability of spontaneous depolarization and slow conduction in the smooth muscle of the CS, providing inherent automaticity.
Studies have shown that this connection is of clinical importance as it may be a source of arrhythmias such as atrial fibrillation. In patients with atrial fibrillation, although myocardial sleeves within the pulmonary veins are a more common source, CS myocardium may also initiate recurrent atrial fibrillation. Since the CS is one of the connections between the right and left atria, with Bachmann's bundle forming the other important connection, reentrant tachycardia involving the CS muscle and both atria are sometimes seen in patients with marked atrial enlargement, especially after a surgical maze procedure.
The vein of Marshall may give rise to atrial fibrillation either by virtue of myocardial extensions into the structure or as a result of node like remnants within the vein or by virtue of the rich autonomic innervation that typically encapsulates the structure.
Cannulation of the CS during interventional procedures may be complicated by obstruction due to Thebesian valves Figures 3 4 — 5. A three-dimensional, functional anatomy study showed that Thebesian valve morphology varied greatly, and included instances of dynamic obstruction.
Studies have demonstrated that valves that obstruct a significant portion of the CS ostium may be successfully transversed by use of modern cannulation techniques i. The CS has been dissected open along its long axis. Note the multiple ostia of various ventricular veins hatched arrows. A remnant of the Thebesian valve that partly covers the ostium of the middle cardiac vein MCV is seen arrow.
Valves can be found in the CS at various locations. Most common are at the ostium of the CS Thebesian valve and at the ostium of the postural lateral vein at the junction of the Great Cardiac vein and CS Vieussen's valve. These valves cover various extents of the area of the orifice. Coronary venous angiogram in the left anterior oblique LAO projection showing a near occlusive valve arrow in the region of the posterolateral vein Vieussen's valve.
In addition, cannulation of the CS for percutaneous mitral valve annuloplasty has been described. The atrial myocardium drains into the CS via the various atrial veins and the vein of Marshall.
The largest atrial vein branch usually occurs opposite to the posterolateral vein coursing between the anterior surface of the left-sided pulmonary veins and the posterior surface of the route of the left atrial appendage. This branch is an embryological remnant of the left superior vena cava. Thus, when it is completely patent, it is known as a persistent left superior vena cava. The branch is known as the vein of Marshall when it is patent in its atrial course.
Occasionally, it may be partially or completely occluded; in which case it is known as the oblique vein of Marshall. The left atrial veins can be used for atrial pacing. When thresholds are poor in the right atrium or precise left atrial-left ventricular synchrony is needed. Specific cannulation of the CS and then placing the lead into an atrial branch can be done. Bi-atrial pacing with both a right and left atrial lead has been attempted for pacing related therapy of atrial fibrillation.
The anterior interventricular vein, the largest and most consistent of the cardiac veins, courses in the interventricular groove adjacent to the left anterior descending artery as it runs towards the base of the heart. It is the most anterior vein seen in the right anterior oblique RAO projection. Although the anterior interventricular vein is the venous parallel of the left anterior descending artery, its proximal tributary courses along the first diagonal branch.
As it approaches the base of the heart, the anterior interventricular vein courses laterally towards the atrioventricular groove to form the great vein. A large tributary that arises proximally drains a significant portion of the anterolateral wall of the left ventricle.
The lateral wall of the left ventricle is typically drained by three distinct veins Figure 6 , largest and most consistent of which is the posterolateral vein. The posterolateral vein occurs directly opposite the vein of Marshall. A lateral view of the left ventricle showing venous anastomoses on the lateral wall. Note, veins interdigitate between the anterior and lateral venous system see text for details.
In addition to receiving tributaries from the anterior interventricular vein, the great cardiac vein also receives tributaries from left posterior vein and the left marginal vein. The phrenic nerve typically crosses superficial to the great cardiac vein and forms variable relations with the lateral vein, posterior branches of the anterolateral vein, and anterior branches of posterolateral cardiac vein.
Because of the thickness of the ventricular myocardium at this site, secondary tributaries of these lateral veins often run an intramyocardial course. The MCV receives communications from the anterior veins as well as from branches from the septal wall and inferior walls of both ventricles. The MCV courses with the posterior descending artery in the posterior interventricular groove and enters the CS close to the right atrial orifice or, rarely, enters directly into the right atrium apical to the septal attachment of the tricuspid valve.
Cardiac autonomic fibres are often found in the posterior crux near the junction of the MCV with the CS. The MCV also has a varied number of branches, the most relevant being the left marginal and inferior veins. Rarely, in 2. This vein courses along the lateral wall together with the posterolateral branches of the right coronary artery and drain the lateral and diaphragmatic walls of the left ventricle. Because of its course, it may be confused with a branch of the MCV.
Its distal branches often interdigitate with branches of the lateral venous system and may be closely related to the phrenic nerve.
The MCV can be specifically targeted for placing a left ventricular lead Table 1. Download citation. Received : 09 December Accepted : 29 November Issue Date : April Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative.
Skip to main content. Importance in device delivery: Balloon catheters can be placed coronary sinus to deliver therapeutics, cardioplegia buffers, or contrast agents, to obtain venograms of the heart.
Numerous device have also been deployed in the coronary sinus as a means to structurally remodel the annulus of the mitral valve e. La longitud del seno coronario en adultos puede variar de 15 a 65 mm.
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