The coronary system is comprised of arteries, arterioles, capillaries,
venules and veins. From the innumerable cardiac capillaries, blood flows
back to the cardiac chambers through venules, which in turn coalesce into
the cardiac veins. Most cardiac veins collect and return blood to the
right atrium through the coronary sinus; there may or not be a Thebesian
valve covering the ostium of the coronary sinus. The major venous vessels
of the human heart are: coronary sinus, the anterior interventricular veins,
left marginal veins, posterior veins of the left ventricle, and the
posterior interventricular veins (see also the
Coronary System Tutorial).
The cardiac veins returns deoxygenated blood (containing metabolic waste
products) from the myocardium to the right atrium. This blood then flows back
to the lungs for reoxygenation and removal of carbon dioxide.
Importance in cardiovascular diseases:
Cardiac veins contain valves preventing back flow; a Thebesian valve may or
may not cover the ostium of the coronary sinus. Typically cardiac veins are
free of atherosclerotic plaques.
Importance in device delivery:
Left heart pacing can be achieved by placing leads into the cardiac veins
through the coronary sinus, which is located within the right atrium. While
cannulating the coronary sinus ostium can be challenging due to the presence
of the Thebesian valve, venous valves within the coronary venous system may
hinder advancement of guide wires, catheters or pacing leads. Stem cell or
other biologic therapies can be delivered to the heart via the coronary