best cardiologist in this area everything you need to know about heart disease Coronary artery disease Coronary artery disease, also known as coronary heart disease, is the most common type of heart disease. It develops when the arteries that supply blood to the heart become clogged with plaque. This causes them to harden and narrow. Plaque contains cholesterol and other substances. As a result, the blood supply reduces, and the heart receives less oxygen and fewer nutrients. In time, the heart muscle weakens, and there is a risk of heart failure and arrhythmias. When plaque builds up in the arteries, this is called atherosclerosis.