Heart disease is the No. 1 cause of death in the United States. Heart disease is a collective term for various problems. Many types of heart disease are related to plaque buildup in the walls of the arteries, or atherosclerosis. As the plaque builds up, the arteries narrow, making it more difficult for blood to flow and creating a risk for heart attack and stroke. Other types of heart disease include heart failure, an irregular heartbeat – or arrhythmia – and heart valve problems.