Coronary Artery Disease

Coronary artery disease (CAD), also known as coronary heart disease (CHD) or coronary atherosclerosis, involves the progressive narrowing of the arteries that nourish the heart muscle. Often there are no symptoms, but if one or more of these arteries become severely narrowed, angina (chest pain) may develop during exercise, stress, or other times when the heart muscle is not getting enough blood. Coronary heart disease can weaken the heart muscle over time and contribute to heart failure and arrhythmias.

Causes of Coronary Heart Disease

The narrowing is due to a buildup of fatty plaque (atherosclerosis) along the artery walls. These deposits are composed mostly of cholesterol, other lipids, and fibrous tissue, such as collagen. Coronary disease appears to be a lifelong process in some people, beginning at an early age and progressing slowly until the vessels become so occluded that the heart muscle no longer gets adequate nourishment. The underlying cause is unknown, although it is seen most frequently in people who live in developed industrialized nations.

Illustration of clot formation in blood vessels

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Diagnosing Coronary Disease

A coronary artery must be narrowed to less than 30% of its original size before there is a serious reduction in the blood flow to the heart muscle served by that vessel. Generally, about 5% of the total cardiac output of blood goes through the coronary arteries; thus there is adequate coronary blood flow to meet normal demands at rest even if the vessels are 70 to 90% occluded. If the coronary arteries are seriously blocked, however, blood flow may not be adequate for any increased demand, such as that of exercise or an emotional upset. If the heart muscle cannot get enough oxygen—a state known as myocardial ischemia—symptoms such as chest pain (angina) or shortness of breath may result.

A presumptive diagnosis of coronary disease is based on a review of symptoms, health history, an electrocardiogram, and an exercise stress test, perhaps with a thallium scan. A more definitive diagnosis requires cardiac catheterization and angiography.

During an exercise stress test, the patient is hooked up to an electrocardiographic monitor (an ECG or EKG machine) and then asked to walk on a treadmill, peddle a stationary bicycle, or climb steps. The ECG monitor will show whether the heart muscle is getting enough blood. An exercise test also detects silent ischemia, a condition with no symptoms in which heart muscle does not get enough blood.

If severe narrowing is suspected, a coronary angiogram may be needed. This examination entails threading a catheter through a blood vessel into the heart, and then injecting a dye into the coronary arteries to make them visible on x-rays.

Medications for Coronary Artery Disease

Various medications constitute the first-line treatment of coronary artery disease. These include:

Beta-Blocking Drugs: These agents act by blocking the effect of the sympathetic nervous system on the heart, slowing heart rate, decreasing blood pressure, and thereby reducing the oxygen demand of the heart. Studies have found that these drugs also can reduce the chances of dying or suffering a recurrent heart attack if they are started shortly after suffering a heart attack and continued for 2 years.

Calcium-Channel-Blocking Drugs: All muscles need varying amounts of calcium in order to contract. By reducing the amount of calcium that enters the muscle cells in the coronary artery walls, spasms can be prevented. Some calcium-channel-blocking drugs also decrease the work-load of the heart and some lower the heart rate as well.

Nitrates: Nitroglycerin may be prescribed to both treat and prevent attacks of angina.

Home Remedies and Alternative Therapies for Coronary Artery Disease

There is no substitute for medical care when considering a serious—even potentially fatal—condition such as coronary heart disease. The first thing to do if you notice any symptoms of a heart problem, including chest pain, is to see your doctor. Medical treatment may be required to prevent heart attack. However, your doctor may recommend nonmedical measures, such as:

  • exercise conditioning,
  • relaxation techniques such as yoga, and
  • a low-fat diet.

These measures may help ease the symptoms of coronary heart disease, especially angina, and may help ease the effects of some risk factors. For example, relaxation techniques may help you overcome stress and block pain impulses by refocusing your concentration. These techniques include meditation, yoga, biofeedback training, and self-hypnosis. For maximum benefit, you should choose a relaxation technique that you are comfortable with and practice it for 20 minutes once or twice a day. In addition to the direct positive effect on your cardiovascular system, relaxation techniques may help you make other lifestyle changes such as stopping smoking and contribute to a general sense of well-being.

Vitamin therapy may also work in conjunction with your medical treatment. High doses of niacin can lower blood cholesterol levels, reducing the buildup of fatty deposits in the arteries. In addition, recent studies indicate that vitamin E, an antioxidant vitamin that also inhibits blood clotting, may help reduce the risk of heart attack. However, do not take any more than the Recommended Dietary Allowance (RDA) of any vitamin without first consulting your doctor; some vitamins in high doses can have toxic effects.

Other more controversial, alternative therapies include garlic, which may be consumed as deodorized pills, and fish oil (omega-3 fatty acid) supplements. Ongoing studies indicate that large amounts of garlic may have a modest cholesterol-lowering effect. Any benefits of fish oil supplements are offset by the increased calorie and fat intake. Thus, experts recommend eating one or two servings of salmon, cod, or other cold-water fish a week rather than taking fish oil pills.