Holly Almond, age 13, of Graham, Wash., for her question:
WHAT CAUSES A HEART ATTACK?
Did you realize that the greatest single cause of death in the United States are heart attacks? Every day of the year about 1,600 people die as a result of heart attacks, and more than that number each day are crippled to some extent for the rest of their lives because of this major health problem.
Almost every single heart attack is caused by a clot of blood that blocks a coronary artery that has become hard and narrow because of arteriosclerosis. The blockage is called a coronary thrombosis.
And what causes arteriosclerosis? It is a hardening, thickening and loss of elasticity in the walls of the arteries in various parts of the body. There's no single cause of the disease but it usually develops over many years, mainly in middle aged or older people. Young people, however, have also been affected by arteriosclerosis. It is apparently the result of an accumulation of fatty materials in the walls of the arteries.
A coronary thrombosis cuts off the blood supply to part of the heart, and as a result, only a small portion of the heart becomes involved. The patient's body, with time, replaces the dead heart muscle with scar tissue and smaller arteries take over the job of supplying the scar tissue with blood.
Heart attacks happen suddenly, but the build up of fatty deposits and calcium in the coronary arteries is a slow process. It takes many years, usually, for an artery to narrow enough so that it can be sealed off by a blood clot.
Diet, smoking and hereditary traits are often involved in the process of developing arteriosclerosis and eventual heart attacks. With the diet, fatty deposits usually come from food containing large amounts of cholesterol. Smoking, doctors strongly believe, increases the likelihood of an attack. Hereditary traits often make a person more susceptible to arteriosclerosis.
A person can take precautions for heart health. Diets should replace items that are heavy in animal fats with vegetable oils. And a person should not eat too much: an overweight person runs a greater risk of heart attack than does one who eats sensibly and stays lean. Also, a person should not smoke.
Most doctors agree that good personal habits and good environment are important factors in heart health.