Heart disease is the leading cause of death in the United States and the United Kingdom, accounting for 64,000+ deaths per year. It is also a major cause of disability.
Heart disease is an inflammatory process. It occurs when arteries become narrowed and hardened due to plaque build-up inside the vessels that supply blood to your heart muscle. This can make it difficult for your heart to pump blood through your body, resulting in chest pain and discomfort and shortness of breath and fatigue.
If some soft plaque breaks of and floats downstream it can block the artery as it narrows. Now blood can’t flow, the surrounding tissue can’t be oxygenated and it dies.
It should be noted that there are two conditions commonly referred to as "heart attacks": myocardial infarction (or MI), which refers specifically to a lack of blood flow caused by coronary artery disease; and non-ST elevation myocardial infarction (NSTEMI), which describes a lack of blood flow caused by some other type of obstruction that does not involve blockage from a clot or plaque build-up.
Heart failure can occur if your heart is unable to continue pumping enough oxygenated blood throughout your body—this can happen when you have chronic high blood pressure or when an artery becomes almost or completely blocked by plaque build-up over time so that no oxygenated blood reaches its destination at all.