Scientists now know that in?ammation is a major component of the process of atherosclerosis. Just as in?ammation of bones and joints can, over time, lead to arthritis, an in?ammatory process inside blood vessels can lead to coronary artery disease or stroke.
Research has not yet pinpointed what causes the low-grade in?am- matory process that may contribute to or even cause atherosclerosis in some people. In the future, a speci?c bacterial or viral infection may be identified, and treatment for coronary artery disease may include antimicrobial or antiviral agents, just as treatment for stomach ulcers now involves antibiotics for the bacteria that is known to be the cause.
In many people who have heart attacks, in?ammation has caused the artery wall itself to absorb fat particles to form a type of plaque some- times called “soft” or “vulnerable” plaque. This plaque, buried in the wall of the artery, is not the same as the plaque that builds up in the channel of an artery. Soft plaque is composed of fat-?lled cells con- tained in a thin shell. If the shell containing the soft plaque breaks open, the plaque spills into the bloodstream, and a blood clot forms at the site of the rupture—the body’s usual response to injury. This blood clot— rather than the plaque—may be the blockage that shuts off the blood supply. The in?amed and swollen artery may be less elastic as well. This process, starting with a type of in?ammation and leading to a blood clot, may explain heart attacks in some people who do not have the tra- ditional risk factors for coronary artery disease, such as high cholesterol.
A marker of the in?ammatory (or immune) response is the presence of a substance called C-reactive protein (CRP) in the blood. Everyone’s body makes CRP, but in different amounts, depending in part on genetic factors and in part on lifestyle. The same factors that tend to contribute to increased risk of heart attack—smoking, overweight, high blood pressure, lack of exercise—contribute to high levels of CRP. A person’s CRP levels can be elevated early in the development of plaque in the arteries, and at the time of a rupture. When a heart attack occurs, CRP levels rise dramatically. As a result, measuring CRP levels in a person’s blood is a good predictor of the development of coronary artery dis- ease and the risk of future heart attacks, as well as a good indicator in an emergency department that a heart attack has occurred.
Nowadays, CRP is measured through a relatively simple test that can be done in a doctor’s of?ce. An elevated CRP level may be as reliable a predictor of heart attack risk in some people as a high level of LDL ( low-density lipoprotein, the harmful choles- terol; see page 132). Research suggests that in some people, high levels of CRP are a signi?cant risk fac- tor for heart disease, independent of high choles- terol. It may be a better predictor in women than in men. Other factors may raise the CRP level in the blood, however. At present, there is no speci?c treat- ment for high CRP levels, except for treating any underlying conditions.

Signs of Cardiac Arrest
A person in cardiac arrest:
• Loses consciousness
• Stops breathing
• Lacks a pulse
Respond immediately:
• Call 911 or the emergency number for your area.
• If you are trained in CPR, use it to help keep the person alive until emergency help arrives to perform defibrillation.
• Look for automated external defibrillator (AED) equipment to use on the person. See also the box on page 155 on using an AED.