Coronary Heart Disease (CHD) occurs when the arteries that supply blood to the heart muscle (coronary arteries) become hardened and narrowed. The arteries harden and become narrow due to the buildup of plaque on the inner walls or lining of the arteries (atherosclerosis). Blood flow to the heart is reduced as plaque narrows the coronary arteries. This decreases the oxygen supply to the heart muscle.

When blood flow and oxygen supply to the heart are reduced or cut off, you can develop:

• Angina - chest pain or discomfort that occurs when your heart is not getting enough blood.
• Heart attack - this happens when a blood clot suddenly cuts off most or all blood supply to part of the heart. Cells in the heart muscle that do not receive enough oxygen-carrying blood begin to die. This can cause permanent damage to the heart muscle.

Over time, CHD can weaken your heart muscle and contribute to:

• Heart failure - the heart is not able to pump blood to the rest of the body effectively. Your heart is failing to pump blood the way it should.
• Arrhythmias - changes in the normal rhythm of the heartbeats.