Submitted by Dr T on September 13, 2010 – 11:45am
Your heart has three coronary arteries that all lay on top of your heart, a Left and a Right coronary artery, of which the Left splits up in two main branches.
All three coronaries have many side branches that eventually go deep into the heart muscle itself, where they supply oxygen-rich (=energy-rich) blood to the muscle cells. This is needed to allow the heart to do its work, no different than the gas that runs the engine in your car.
Coronary arteries can develop blockages that may limit the flow of blood. When you have a blockage some of that flow is obstructed and the heart muscle in that region no longer gets enough blood. If there is a blockage in the Left coronary artery before it splits in two, it is called a Left Main Stenosis, which may be particularly dangerous, because it affects the blood flow to the most important part of your heart.
Sometimes the effect of a blockage is only noticeable during exercise when the heart needs more fuel than it gets. When the obstruction is significant enough there may not even be enough blood supply at rest. These condition cause symptoms called Angina Pectoris. Angina can be experienced as some kind of chest pain, pressure, or “indigestion”, but other patients may simply feel more tired than usual, or think they have some sort of flu.
If there is a complete obstruction, usually a heart attack occurs, with heart muscle dying. If that happens in a bad spot, a patient might die, but luckily most of the time it only a small amount of damage occurs.
A good place to start is to take a look here:
https://www.cardiachealth.org/heart-information/anatomy-of-heart and:
https://www.cardiachealth.org/heart-information/coronary-artery-disease-angina
and this Blog:
https://www.cardiachealth.org/ca-blog/is-heart-bypass-surgery-necessary-to-treat-unstable-angina/