In the United States and many other industrialized countries, heart disease is the leading cause of death. According to the United States Centers for Disease Control and Prevention (CDC), more than 700,000 people in the United States die of heart disease each year. By far the most common type of heart disease in the United States is coronary heart disease, in which the arteries that nourish the heart become narrowed and unable to supply enough blood and oxygen to the heart muscle. However, many other problems can also affect the heart, including congenital defects (physical abnormalities that are present at birth), malfunction of the valves inside the heart, and abnormal heart rhythms. Any type of heart disease may eventually result in heart failure, in which a weakened heart is unable to pump sufficient blood to the body.


CORONARY HEART DISEASE
Coronary heart disease, the most common type of heart disease in most industrialized countries, is responsible for nearly 500,000 deaths in the United States yearly. It is caused by atherosclerosis, the buildup of fatty material called plaque on the inside of the coronary arteries. Over the course of many years, this plaque narrows the arteries so that less blood can flow through them and less oxygen reaches the heart muscle.

The most common symptom of coronary heart disease is angina pectoris, a squeezing chest pain that may radiate to the neck, jaw, back, and left arm. Angina pectoris is a signal that blood flow to the heart muscle falls short when extra work is required from the heart muscle. An attack of angina is typically triggered by exercise or other physical exertion, or by strong emotions. Coronary heart disease can also lead to a heart attack, which usually develops when a blood clot forms at the site of a plaque and severely reduces or completely stops the flow of blood to a part of the heart. In a heart attack, known to doctors as myocardial infarction, part of the heart muscle dies because it is deprived of oxygen. This oxygen deprivation is also responsible for the crushing chest pain characteristic of a heart attack. Other symptoms of a heart attack include nausea, vomiting, and profuse sweating. About one-third of heart attacks are fatal, but patients who seek immediate medical attention when symptoms of a heart attack develop have a good chance of surviving.

One of the primary risk factors for coronary heart disease is the presence of a high level of a fatty substance called cholesterol in the bloodstream. High blood cholesterol is typically the result of a diet that is high in cholesterol and saturated fat, although some genetic disorders also cause the problem. Other risk factors include smoking, high blood pressure, diabetes mellitus, obesity, and a sedentary lifestyle. Coronary heart disease was once thought to affect primarily men, but this is not the case. The disease affects an equal number of men and women, although women tend to develop the disease later in life than men do.

Coronary heart disease cannot be cured, but it can often be controlled with a combination of lifestyle changes and medications. Patients with coronary heart disease are encouraged to quit smoking, exercise regularly, and eat a low-fat diet. Doctors may prescribe a drug such as lovastatin, simvastatin, or pravastatin to help lower blood cholesterol. A wide variety of medications can help relieve angina, including nitroglycerin, beta blockers, and calcium channel blockers. Doctors may recommend that some patients take a daily dose of aspirin, which helps prevent heart attacks by interfering with platelets, tiny blood cells that play a critical role in blood clotting.

In some patients, lifestyle changes and medication may not be sufficient to control angina. These patients may undergo coronary artery bypass surgery or percutaneous transluminal coronary angioplasty (PTCA) to help relieve their symptoms. In bypass surgery, a length of blood vessel is removed from elsewhere in the patient?s body?usually a vein from the leg or an artery from the wrist. The surgeon sews one end to the aorta and the other end to the coronary artery, creating a conduit for blood to flow that bypasses the narrowed segment. Surgeons today commonly use an artery from the inside of the chest wall because bypasses made from this artery are very durable. In PTCA, commonly referred to as balloon angioplasty, a deflated balloon is threaded through the patient?s coronary arteries to the site of a blockage. The balloon is then inflated, crushing the plaque and restoring the normal flow of blood through the artery. See also Coronary Heart Disease.