Heart disease is a general term that means that the heart is not working normally. Babies can be born with heart disease. This is called congenital heart disease. If people get heart disease later, it is called acquired heart disease. Most heart disease is acquired.

Types of heart disease
The three most common types of acquired heart disease are:
 Coronary Artery Disease (acronym CAD) – This is a problem with the blood vessels that deliver blood to the heart muscle. If these blood vessels get very small, or if they become blocked, blood cannot flow through them normally. Since less blood is supplied to the heart muscle, the muscle cannot work at normal capacity. The heart muscle can become sick and weak. Heart muscle can even die if blood flow stops. Blocked arteries in the heart are often caused by smoking, high cholesterol, high blood pressure, diabetes, and inherited traits from parents. All of these problems damage the lining of the heart's blood vessels and make them become narrowed or blocked completely.
 Congestive Heart Failure (CHF) – This is a condition that means that the heart is not pumping at normal levels. Two common causes are a weak or sick heart muscle and abnormal heart valves. The valves may not let enough blood through because they are too narrowed. Or the valve may "leak" and let blood flow backwards (the wrong direction) inside the heart. When the heart valves do not work normally, the heart muscle has to do extra work and it can become tired.
 Bad Heart Rhythms – This is a problem with electrical activity in the heart. This can make the heart beat too fast or too slow. Very bad heart rhythms may make the heart stop pumping blood. The heart needs a normal rhythm to pump the blood well. If the rhythm is too fast, the heart may not have time for blood to enter the chambers, so there is not enough blood moving through the heart with each beat. If the heart is too slow, there may not be enough contractions of the heart to supply the body with the blood that it needs.

Symptoms
A person can have heart disease and not feel sick. Some people with heart disease have symptoms. This is when there are changes or pain in the body to show a disease is there. Some symptoms of heart disease are:
 Pain in the chest—the heart muscle is not getting enough flow to keep it going.
 Trouble breathing—blood may back up into the lungs.
 Palpitations (a feeling that the heart is beating too fast, too hard, or not regularly).
 Swelling of feet or legs—blood is backing up from the heart into the lower body.
 Feeling weak because the body and brain are not getting enough blood to supply them with oxygen.
 Cyanosis (skin turning a blue colour) means that too little oxygen is in the bloodstream to supply the cells in the body.

Deaths
Heart disease is the biggest killer of both men and women in the United States, England, Wales, and Canada. For example, heart disease causes 4 out of every 10 deaths in the United States. This is more than all kinds of cancer put together. Also, one person dies of heart disease about every minute in the United States alone.

Congenital heart disease
Congenital heart disease refers to a form of heart problem that starts before birth (congenital). Congenital heart disease includes a large number of conditions. The formation of the heart before birth is very complex and is sometimes abnormal. For example, if a part of the main artery that comes from the heart is narrowed, that is called coarctation of the aorta. There may be holes inside the heart which keep the blood from flowing normally inside the heart. Other congenital heart problems are caused by abnormal heart valves. In some cases, congenital heart problems are discovered at birth. Other times the problems may not be detected until the person is older.

Other websites
 Mayo Clinic 
 WebMD Heart Disease 
 Freedom Years Heart Disease  
 American Heart Association 
 HealthBlaster.com-Heart Health