Coronary Artery disease is a buildup of plaque inside the coronary artery of the heart. This plaque buildup is referred to as atherosclerosis and it takes years to result in Coronary Artery Disease.
The plaque buildup can eventually result in a hardening of the arteries and reduces the blood flow through the coronary artery. Over time, ruptured plaque also hardens and blocks the blood flow in the artery. Over time, CHD can weaken the heart muscle and lead to heart failure and arrhythmias.
The blockage in the artery could also result in a heart attack due to lack of oxygen and blood to the heart. This may be felt through angina, a painful pressure in the chest, which spreads outwards to the arm.