Because diseases of the heart disorder and blood vessels are the leading cause of death and disability in industrialized countries, these diseases have been called, collectively, the “black plague” of our time. There are many reasons for the breakdown of the cardiovascular system.

The most common one is coronary artery disease, or deterioration of the coronary arteries, two blood vessels that branch off the aorta to nourish the heart muscle with fresh blood. In the Western world, coronary artery disease accounts for nearly a third of all deaths.

What Happens to the Heart in Coronary Artery Disease?

Most of the heart gets the blood it needs through the two coronary arteries. If one of these arteries is blocked, part of the heart may die for lack of blood. A heart attack, or myocardial infarction, is the outward sign of this tissue death. Most infarctions occur in people 40 to 60 years old, but children as young as 5 have been known to have heart attacks.

Coronary artery disease is almost always traceable to a condition called atherosclerosis, in which fatty deposits, or atheromas, attach themselves to the inner lining of an artery. Though the condition has become the bane of prosperous, modern societies, it did not originate in the 20th century; signs of it have been found in ancient Egyptian mummies.

In atherosclerosis, arteries that were once smooth and elastic become rough, inflexible, and smaller than before. As they narrow, the volume of blood they can transport is progressively reduced. As a mass of atheroma grows, it may turn into a hard, chalky plaque that further scars the arterial wall. The resulting pinch points in a vessel become natural sites for the formation of blood clots.

In coronary thrombosis, a stationary blood clot formed in a coronary artery shuts off the flow of blood entirely. In coronary embolism, the blockage is caused by a clot that moves through the bloodstream and becomes lodged in an already narrowed coronary artery.

What are Other Risk Factors in Coronary Artery Disease?

Topping the list of unavoidable factors linked to coronary artery disease is heredity. If both your parents had atherosclerosis, your risk of developing it is greater than that of most other people. Age is another factor: detectable symptoms of coronary artery disease are uncommon before the age of 50, but they are increasingly prevalent thereafter.

Female sex hormones seem to offer some protection from coronary artery disease; women rarely develop it before the menopause, but after 60 are almost as susceptible to it as men.

Smoking a pack or more of cigarettes each day is estimated to at least double an individual’s chances of coronary disease. Chronic high blood pressure, diabetes, obesity, emotional stress, and lack of exercise also raise the probability of developing atherosclerosis. By evaluating your own health habits and by changing them if necessary, you stand a god chance of protecting yourself against this epidemic disease.

Does Cholesterol Really Matter?

Cholesterol is one of several fatty compounds that are found in human blood and tissue. Manufactured in the liver, it is essential for producing new cells and certain hormones. It is also taken into the body in food; meat, butter, milk, cheese, and eggs all contain cholesterol.

Doctors have noted that victims of heart disease tend to have abnormally high levels of cholesterol in their blood. And scientists believe that atherosclerosis begins when high blood levels of cholesterol penetrate the smooth lining of the arteries, forming small deposits there. The process, gradual if the arteries are otherwise healthy, is believed to proceed much faster if a person has high blood pressure, and if he or she smokes.

Not everyone whose diet is rich in cholesterol develops atherosclerosis, however, perhaps because individuals vary in the way they process the substance. Everyone’s body contains more than a dozen proteins that attach themselves to cholesterol. One is LDL (low-density lipoprotein), which is believed to collect cholesterol and deposit it in the cells. Another is HDL (high-density lipoprotein), which is thought to pick up excess cholesterol and help the body eliminate it. Those with lots of HDLs seem to have fewer heart attacks than others.

Although there is still much to be learned about the role of cholesterol and of LDL and HDL, most doctors believe that an individual can reduce the risk of heart disease by cutting down on those foods that are high in animal fats. This should retard the buildup of fatty deposits in the coronary arteries, and some doctors believe it may even cause already-formed atheromas to shrink.

Does a Heart Attack Always Mean Invalidism or Death?

No doubt about it: a heart attack is a terrifying experience. But the fact is that two out of three people survive the first heart attack. If death occurs, it is usually within two hours of the attack. The odds are with a person who lives for a day, and after three weeks, long-term survival is probable. If you sustain a coronary thrombosis and live ten years, your life expectancy is the same as that of a person who has never had an attack.

Just like a broken bone, a damaged heart heals. But after all but the mildest attacks, a period of two to six weeks in the hospital is likely to be necessary. People who were used to exercising and engaging in sports before their attack can expect to return gradually to their favorite activities. And after about three months (sometimes sooner), most people can go back to their old jobs.