Organs
Heart
Interactive Heart
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The human heart is about the size of a closed fist. It is located behind the lower part of the breastbone, extending more to the left of the midline than to the right. Blood from the body returns to the right atrium through two large veins, the superior and inferior venae cavae; in addition the blood that has supplied the heart muscle is drained directly into the right atrium through the coronary sinus. Rhythmic contractions of the right ventricle expel the blood through the pulmonary arteries into the capillaries of the lung, where the blood receives oxygen. The lung capillaries then empty into the pulmonary veins, which in turn empty into the left atrium. Contraction of the left ventricle rhythmically propels the blood into the aorta and from there to all arteries of the body, including the coronary arteries which supply the heart muscle.
Diseases of the heart
Disorders of the heart kill more Americans than any other disease. They can arise from congenital defects, infection, narrowing of the coronary arteries, high blood pressure, or disturbances of heart rhythm. In 1967 a human heart from one person was transplanted into the body of another.
The first heart transplant
South African surgeon Christian Barnard performed the first such transplant; many surgeons soon adopted the procedure. However, most patients were dying soon after a transplant and the number of operations dropped from 100 in 1968 to 18 in 1970. The major problem was the body’s natural tendency to reject tissues from another individual. Fluids would invade the chest, livers would bloat, immune systems would reject the new heart and patients would die.
During the 1970’s surgeons continued their work in transplant surgery and combined it with the use of drugs that suppressed the immune system, thus lengthening the survival rate. In 1980 a new experimental drug called cyclosporine became available for use by selected transplant surgeons. Combining cyclosporine with steroids and other drugs produced results that were amazing and in 1983 the Food and Drug Administration approved the use of cyclosporine with steroids for all transplant patients. Between 1980 and 1989 the number of transplant patients increased by a factor of 20. In 2003 there were 2,057 heart transplants and 29 heart/lung transplants. During this time period 523 people died while waiting for a heart or heart/lung transplant.
What is heart disease?
The leading cause of death in the United States and a major cause of disability, heart disease is a term used to describe many heart disorders, including high blood pressure, coronary artery disease, and clogging of the arteries. Almost 700,000 people die of heart disease in the U.S. each year, about 29 percent of all U.S. deaths. The most common heart disease in the U.S. is coronary heart disease, which can lead to heart attacks. Extensive clinical and statistical studies have identified several factors that increase the risk of coronary heart disease and heart attack. Major risk factors are those that research has shown significantly increase the risk of heart and blood vessel disease. Other factors are associated with increased risk of cardiovascular disease, but their significance and prevalence haven't yet been precisely determined. They're called contributing risk factors.
The American Heart Association has identified several risk factors. Some of them can be modified, treated or controlled, and some can't. The more risk factors you have, the greater your chance of developing coronary heart disease. Also, the greater the level of each risk factor, the greater the risk.
What are the major risk factors?
Major risk factors that can't be changed.
Increasing Age Over 83 percent of people who die of coronary heart disease are 65 or older. At older ages, women who have heart attacks are more likely than men are to die from them within a few weeks.
Gender Men have a greater risk of heart attacks than women and have attacks earlier in life. Even after menopause, when women's death rate from heart disease increases, it's not as great as men's.
Heredity (Including Race) African Americans have more severe high blood pressure than Caucasians and a higher risk of heart disease. Heart disease risk is also higher among Mexican Americans, American Indians, native Hawaiians and some Asian Americans. This is partly due to higher rates of obesity and diabetes. Most people with a strong family history of heart disease have one or more other risk factors. Just as you can't control your age, sex and race, you can't control your family history, which is why it is even more important to treat and control any other risk factors you have.
Reduce your risk
Risk factors that you can modify, treat or control by
Changing your lifestyle or taking medicine.
Tobacco Smoke Smokers' risk of developing coronary heart disease is 2-4 times that of nonsmokers. Cigarette smoking is a powerful independent risk factor for sudden cardiac death in patients with coronary heart disease; smokers have about twice the risk of nonsmokers Cigarette smoking also acts with other risk factors to greatly increase the risk for coronary heart disease. People who smoke cigars or pipes seem to have a higher risk of death from coronary heart disease (and possibly stroke) but their risk isn't as great as cigarette smokers'. Exposure to other people's smoke increases the risk of heart disease even for nonsmokers.
Cholesterol As blood cholesterol rises, so does risk of coronary heart disease. When other risk factors (such as high blood pressure or tobacco smoke) are present, this risk increases even more. A person's cholesterol level is also affected by age, sex, diet and heredity. High Blood High blood pressure increases the heart's workload, causing the heart to thicken and Pressure become stiffer. It also increases your risk of stroke, heart attack, kidney failure and congestive heart failure. When high blood pressure exists with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke increases several times.
Physical An inactive lifestyle is a risk factor for coronary heart disease. Regular, moderate-to-Inactivity vigorous physical activity helps prevent heart and blood vessel disease. The more vigorous the activity, the greater your benefits. However, even moderate-intensity activities help if done regularly and long term. Exercise can help control blood cholesterol, diabetes and obesity, as well as help lower blood pressure in some people. Obesity and People who have excess body fat - especially if a lot of it is at the waist - are more likely Overweight to develop heart disease and stroke even if they have no other risk factors. Excess weight increases the heart's work. It also raises blood pressure and blood cholesterol and triglyceride levels and lowers HDL ("good") cholesterol levels. It can also make diabetes more likely to develop. Many obese and overweight people may have difficulty losing weight. But by losing even as few as 10 pounds, you can lower your heart disease risk.
Diabetes Diabetes seriously increases your risk of developing cardiovascular disease. Even when Mellitus glucose (blood sugar) levels are under control, diabetes increases the risk of heart disease and stroke, the risks are greater if blood sugar is not well controlled. About three-quarters of people with diabetes die of some form of heart or blood vessel disease. If you have diabetes, it's extremely important to work with your healthcare provider to manage it and control any other risk factors you can.
Individual responses to stress and drinking too much alcohol can also be contributing factors to heart disease. Scientists have noted that stress in a person's life, not only affects their health behaviors and socioeconomic status but also can lead to coronary heart disease. Drinking too much alcohol can raise blood pressure, cause heart failure and lead to stroke. It can also lead to high triglycerides, cancer and other diseases, and produce irregular heartbeats.
The risk of heart disease in people who drink moderate amounts of alcohol (an average of one drink for women or two drinks for men per day) is lower than in nondrinkers. One drink is defined as 1-1/2 fl. oz. of 80-proof spirits (such as bourbon, Scotch, vodka, gin, etc.), 1 fl. oz. of 100-proof spirits, 4 fl. oz. of wine or 12 fl. oz. of beer. It's not recommended that nondrinkers start using alcohol or that drinkers increase the amount they drink.
