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Coronary heart disease is the narrowing or blockage of the arteries and vessels that provide oxygen and nutrients to the heart. It is caused by a condition called atherosclerosis, which is the gradual buildup of fatty materials on the arteries” inner linings. The blockage that results from the buildup restricts blood flow to the heart. When the blood flow is completely cut off, a heart attack can occur.
Coronary heart disease also may be called coronary artery disease or simply heart disease. It is the leading cause of death in the United States among men and women.
When the heart works harder and needs more oxygen, the coronary arteries expand. But buildup of fatty materials, or plaque, from atherosclerosis causes the arteries to harden and narrow. If the arteries are unable to expand because of coronary artery disease, the heart is deprived of oxygen. The heart muscle can”t work properly without oxygen. The reduced blood flow and oxygen supply may cause angina, which is pain in the chest. It also may cause shortness of breath or other symptoms. Complete blockage or clotting at the site where the blood enters the heart can cause a heart attack.
Coronary heart disease can worsen over time. The heart muscles may weaken, even though no symptoms may be evident. Eventually, this leads to heart failure. In heart failure, the heart doesn’t suddenly stop, but fails to pump blood to the body the way that it should. Coronary heart disease also can lead to heart arrhythmias, or changes in the normal rhythm of heartbeat. These can be serious.
According to the American Heart Association, coronary heart disease caused more than 250,000 deaths in 2004. But the number of deaths from the disease declined 33% from 1994 to 2004. Although about 325,000 people a year die of coronary attacks in hospital emergency departments without even being hospitalized, more than 15 million people in America live with a history of heart attack, angina pectoris, or both. More of these are males, but not by a wide margin. Black males have a higher death rate per 100,000 than white males, and men generally have a higher chance of dying from coronary heart disease than women.
Coronary heart disease is caused by atherosclerosis. Some risk factors for coronary heart disease can’t be changed, such as inheriting a genetic risk for the disease.
Causes and risk factors
Age is a major risk factor for death from coronary heart disease. Over 83% of people who die from coronary heart disease are over age 65. Gender plays a role too, since men have a higher risk of heart attacks. Men tend to get heart disease earlier than women. While mean are at higher risk for coronary heart disease by about age 45, women are at risk for heart disease later in life, beginning at about age 55. People whose parents had heart disease also are at higher risk for coronary heart disease. Certain racial groups have higher risk as well, often because of a greater tendency toward obesity, high blood pressure, or diabetes.
Other risk factors can be affected by diet and lifestyle changes. Smoking is a big contributor to coronary heart disease. Not only do smokers have a risk two to four times that of nonsmokers of developing coronary heart disease, but they also have a higher risk of heart attack from the disease. In fact, a smoker with coronary heart disease is twice as likely as a non-smoker with coronary heart disease to die suddenly from the disease.
Cholesterol and saturated fat play a role in developing coronary heart disease. The body produces cholesterol and a person’s age, sex, and heredity can affect cholesterol levels. But diet also affects cholesterol. Both cholesterol and saturated fat tend to be found in the same foods. Dietary sources of both are meat, eggs, and other animal products. Risk of developing coronary heart disease rises steadily as levels of low-density lipoprotein (LDL) cholesterol rise or if a person has high cholesterol levels combined with high blood pressure and smoking.
Other diseases and conditions contribute to risk of coronary heart disease. High blood pressure makes the heart work harder and weakens it over time. Diabetes mellitus can be a serious risk for coronary heart disease and cardiovascular disease, which includes other disease to other arteries throughout the body. About three-fourths of people with diabetes die from heart disease or blood vessel disease.
Weight and physical activity play a role in risk of coronary heart disease. Being overweight makes the heart work harder to do its everyday job of pumping blood to the body. Even when people have no other risk factors, obesity greatly increases risk of heart disease, particularly if weight is concentrated at the waist. Excess weight also raises blood pressure and affects cholesterol and triglyceride levels. Losing as little as 10 pounds can decrease risk for coronary heart disease, though maintaining a healthy weight is best. Being inactive contributes to weight gain and all of the associated conditions that then lead to coronary heart disease.
Stress also may play a role in coronary heart disease risk. However, the real problem is how people react to stress. For instance, overeating in response to stress leads to risk factors listed above. Drinking too much alcohol can cause some of the conditions listed above and lead to heart failure. However, studies have shown that moderate amounts of alcohol, described as about 1.5 fluid oz. of 80-proof spirits, 1 fluid oz. of 100-proof spirits, 4 fluid oz. of wine, or 12 fluid oz. of beer per day, may be good for the heart. The American Heart Association does not recommend that people who do not drink begin drinking or that anyone increase alcohol intake to meet these amounts, however.
The restricted blood flow to the heart caused by narrowing arteries may not produce any symptoms at first and many people are completely unaware that they have coronary heart disease. As the plaque builds up, symptoms begin to develop. One of the first signs may be chest pain that is triggered by physical or emotional stress. This pain often is referred to as angina. The pain feels much like pressure or tightening in the chest or it may be felt in the arm, neck, jaw, shoulder, or back. Sometimes the pain is confused with indigestion. Women may notice pain more often in the back or arm than in the chest and the pain may be brief and pass quickly.
Shortness of breath also is a symptom of coronary heart disease. This results from the heart’s decreasing ability to pump enough blood to the body to meet its needs. The person with shortness of breath also may feel very tired.
The most serious symptom of coronary heart disease is heart attack. Although some heart attacks start suddenly and are clearly occurring, most start slowly with uncertain symptoms. Discomfort in the center of the chest that lasts for several minutes that feels like squeezing, fullness, or pain is a sign that a heart attack is occurring or about to occur. The pain also may go away and come back. The pain may occur in one or both upper arms, the back, neck, jaw, or stomach. A person may experience shortness of breath with or without chest pain. Some people break out in a sweat or experience nausea or lightheadedness.
A physician will ask questions about edical history, symptoms, and relatives with heart disease, as well as diet and lifestyle. A physical examination and routine blood tests also may be ordered as part of the evaluation. In addition, several examinations can be done to diagnose and evaluate coronary heart disease. These include:
- Resting electrocardiogram (ECG or EKG). This records electrical signals as they travel through the heart and usually is performed in a physician’s office. It is noninvasive and involves placing electrodes on the body.
- Holter monitoring. Also called ambulatory electrocardiography, this involves wearing a portable EKG unit for 24 hours to monitor inadequate blood flow to the heart as a person goes about everyday activities.
- Angiogram. This is an x ray of the heart taken when a small tube, or catheter, is inserted into the arteries through a blood vessel in the groin or arm. The tip of the catheter can be guided to the coronary arteries and contrast is released. The contrast will be visible on x rays and will help show blood flow in the heart’s chambers. Today, angiograms can be performed through the use of contrast and imaging with computed tomography or magnetic resonance imaging.
- Computed tomography (CT) scan. A CT scan, which is a cross-sectional x ray of the body or an organ of the body, can show images of the arteries to determine atherosclerosis. Ultra-fast CT imaging also can detect calcium within plaque.
- Magnetic resonance imaging (MRI). This noninvasive method may be used to examine the tissues of the heart. MRI uses no radiation. Magnetic resonance angiography provides an alternative to the more invasive method that involves introducing a catheter into the body.
- Other imaging methods may be used to detect coronary heart disease, such as single photon emission computed tomography (SPECT).
There are many ways to treat coronary heart disease, and the choice of treatment depends on the cause of the disease and its severity. Treatment ranges from lifestyle changes and use of medication to surgical procedures. People with less severe disease and fewer risk factors may be able to manage their disease through lifestyle changes and drug therapy. Changes in diet and an increase in exercise, as well as quitting smoking, can gain control of coronary heart disease. Often all treament procedures are used. Lifestyle factors such as diet and exercise are first line prevention and treatment methods. They are to be continued even after beginning medications and following surgery.
Medications used to treat coronary heart disease include:
- cholesterol-lowering medicines such as statins and fibrates
- blood thinners, or anticoagulants, to prevent blood clots from forming
- aspirin, also to help prevent clotting
- blood pressure medicines to lower blood pressure, such as angiotensin-converting enzyme (ACE) inhibitors
- calcium channel blockers, to relax blood vessels and lower blood pressure
- beta blockers to slow heart rate and lower blood pressure
Surgery or other procedures also may be recommended to treat coronary heart disease. A physician may be able to use a catheter to guide a tiny balloon into the artery. Once in place, the balloon is inflated and used to widen the artery by pushing the plaque up against the artery wall, Next, a stent, or mesh tube, is placed in the widened area to help keep the artery opened and clear for adequate blood flow.
Coronary artery bypass surgery reroutes, or bypasses, blood flow around the arteries that have clogged to improve blood flow to the heart. To perform the procedure, the surgeon takes a healthy blood vessel from another part of the body and uses it to create a detour around the clogged artery. This procedure requires open heart surgery and is reserved for people with multiple areas of artery blockage.
Heart attacks from coronary heart disease require emergency medical treatment.
Nutrition is key to preventing and controlling coronary heart disease. The American Heart Association recommends that adults get no more than 300 mg of cholesterol a day in their diet and that those with heart disease get no more than 200 mg a day. It also is important to limit cholesterol that comes from animal-based foods and from saturated fats. All animal foods contain some cholesterol, so eating lean meats, fish, and poultry in smaller servings helps to control the amount eaten. Eating fat-free or low-fat dairy products also helps keep cholesterol and fats in check.
Controlling blood pressure helps prevent or manage coronary heart disease. A diet low in salts and high in fruits, vegetables, and whole grains helps to control blood pressure. The DASH diet is a balanced approach to controlling hypertension.
Eating lots of sugars and simple carbohydrates can lead to or complicate diabetes and affect triglyceride levels, increasing risk of coronary heart disease. It is important for people with diabetes to control their intake of white bread, bagels, cakes, soft drinks, and other carbohydrates. Studies show that whole-wheat breads, brown rice, and legumes are healthier choices to provide carbohydrates and protein in the diet. Even people with coronary heart disease who do not have diabetes should try to eat the recommended daily amounts of grains and fats and to get them from whole grains when possible.
In the past, there have been recommendations to follow high-protein, high-fat diets to control coronary heart disease. Studies have not shown these types of diets, such as the Atkins diet, to be successful at controlling weight long term or to reducing coronary heart disease. Research has shown that diets lower in carbohydrates and higher in vegetable sources of fat and protein moderately reduce the risk of coronary heart disease in women. Certain foods, such as fish and foods high in fiber (whole grains, fruits, and fresh vegetables) are healthy foods for the diets of people with coronary heart disease.
The most important aspect of nutrition and diet for people with coronary heart disease is to eat a balanced diet that helps them to lose and manage weight. The United States Department of Agriculture (USDA) and the United States Department of Health and Human Services revised the Dietary Guidelines for Americans in 2005. The guidelines are science-based and outline advice for choosing a nutritious diet and maintaining a healthy weight. The 2005 guidelines also address physical activity and food safety and make recommendations for special population groups. Finally, calorie requirements and servings are based more on gender, age, and level of physical activity, while in 2000, the servings were more uniform for all adults. The USDA also revised the traditional food pyramid to make it customized for individuals. These guidelines form the basis for healthy eating. The American Heart Association and the American Dietetic Association also offer heart healthy diet recommendations, as do family physicians and cardiologists.
Some patients with coronary heart disease will be referred for cardiac rehabilitation, particularly following bypass surgery or if they have experienced angina or a heart attack. The rehabilitation may consist of an exercise plan to help regain stamina safely based on individual ability and needs, and education, counseling, and training. Training may include ways to better manage stress, as well as how to manage other lifestyle factors that contribute to coronary heart disease.
Coronary heart disease can be successfully managed and treated in many cases. Advances in diagnosis and techniques such as stenting have helped to improve the lives of people with the disease, bringing about a significant decline in death rates from coronary heart disease since the mid-1980s. However, as the leading cause of death in the United States, coronary heart disease is a serious condition that is best prevented and that requires careful management and attention once diagnosed. The more risk factors a person has, the worse the prognosis.
Preventing coronary heart disease begins with knowing the risk factors and taking action to act on those factors. Managing all those contributing factors that can be avoided goes a long way in preventing the advancement of atherosclerosis and eventual coronary heart disease. By quitting smoking, moderating alcohol use, controlling blood pressure, preventing diabetes, and maintaining healthy cholesterol levels, people can prevent many of the causes of coronary heart disease. Maintaining a healthy body weight by eating a balanced diet with healthy-sized portions and participating in regular physical activity helps to prevent the disease. Those with known hereditary or other risk factors for coronary heart disease should have regular physical examinations with their physicians and should pay careful attention to the signs and symptoms of coronary heart disease and heart attack.
American Heart Association No-Fad Diet: A Personal Plan for Healthy Weight Loss. Clarkson Potter Publishers, 2005.
American Heart Association: To Your Health. A Guide to Heart-Smart Living. Clarkson Potter Publishers, 2001.
American Dietetic Association. 120 South Riverside Plaza, Suite 2000. Chicago, IL 60605. (800) 877-1600. <http://www.eatright.org>
American Heart Association. 7272 Greenville Ave., Dallas, TX 75231. (800) 242-8721. <http://www.americanheart.org>
National Heart, Lung, and Blood Institute. P.O. Box 30105, Bethesda, MD 20284. (301) 592-8573. <http://www.nhlbi.nih.gov>
Teresa G. Odle