Heart disease

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Heart disease is a general term for conditions that affect the working of the heart. In 2005, 652,000 Americans died of heart disease (not counting stroke), accounting for 27.1% of all deaths in the U.S.

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Mortality

By far the leading killer in the United States, accounting for 918,000 deaths in 2002 (37% of all deaths), is heart disease and stroke.

Atherosclerosis

The major cause of death is hardening of the arteries, or atherosclerosis (pronounced ath-uh-roh-skluh-ROH-sis). Layers of plaque build up on the inside of coronary arteries. The plaque is comprised of cholesterol, lipids, and cellular debris. Too much plaque will reduce the flow of blood to the heart muscle, which eventually gives out in a heart attack (myocardial infarction).

Atherosclerosis is a normal part of aging, and begins about ten years earlier in men than women, and this is the major reason women live longer. The rate of plaque buildup varies greatly, even among people with similar diets; a family history of heart attacks is a bad sign. The onset may appear to be sudden, because a blockage of the arteries are wider than they have to be, and a narrowing of the arteries of more than 75% is needed to impede blood flow seriously. If enough plaque has built up, there is grave risk that a clot will come along, block all blood, and kill the affected organ—which might be the heart or the brain. High blood pressure (hypertension) and high blood-cholesterol are warning signs. Obesity and cigarette smoking weaken the body’s natural resistance; diabetes raises the level of blood lipids and speeds the buildup of plaque.

To avoid or postpone atherosclerosis physicians recommend the elimination of cigarette smoking, a reduction of dietary saturated fat, a reduction in high blood pressure, more exercise, and weight control. Perhaps Americans are heeding this advice; the age-adjusted annual death rate from heart disease plunged from 559 deaths (per 100,000) in 1960 to 240 in 2002, and it continues to fall. In addition to life style changes, major credit goes to advances in surgery, especially balloon angioplasty (which widens the artery by flattening the plaque) and bypass surgery (which routes blood around the blockage). Survival of patients who reach the hospital has improved markedly, but about one-third of the 1,500,000 Americans who have a heart attack each year will die. About 250,000 people will die from their heart attack before they reach the hospital. For people who survive a heart attack, about 20% of women and 16% of men will have another during the next four years.

Stroke

Similar to heart disease, but counted separately, is stroke or "cerebrovascular accident" (CVA). It is the third most common cause of death, taking 163,000 American lives in 2002. It involves a sudden impairment of brain function, usually caused by atherosclerosis or a blood clot that cuts of the flow of blood to the brain. Stroke affects the brain, while a heart attack affects the heart. About half the fatal strokes come before age 70. Smoking, high cholesterol, diabetes, aging, and heritable defects make stroke more likely. The death rate fell in half between 1970 and the 1990s, perhaps due to better diets, exercise, and less smoking. If not immediately fatal a stroke may be more or less debilitating; therapy is often successful.

Other heart diseases

  • Cardiomyopathy - disease or deterioration of the heart muscle which can cause arrhythmia or tachycardia and may result in sudden cardiac death.
  • Cardiovascular disease - diseases that directly affect the heart and/or the veins and arteries that supply blood to the heart and may be caused by diabetes mellitus, high cholesterol or hypertension
  • Coronary heart disease - a condition which can lead to a myocardial infarction (heart attack) that may be fatal, or angina pectoris (chest pains).
  • Ischaemic heart disease - disease where there is a restricted blood flow to the heart.
  • Heart failure - or congestive cardiac failure, a condition whereby the heart fails to fill with enough blood or pump it adequately around the body.
  • Hypertensive heart disease - heart disease caused by high blood pressure.
  • Inflammatory heart disease - inflammation of the heart muscle (myocardium), heart lining (endocardium), valves or the surrounding tissue.
  • Valvular heart disease - disease of one or more of the valves of the heart. This may be a congenital birth defect or a condition acquired later in life.

Further reading

  • Lilly, Leonard S, ed. Pathophysiology of Heart Disease (4th ed. 2006); basic textbook, 464pp

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See also

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