6 Mayıs 2008 Salı

Heart Disease



Listen to your heart. Many women don't recognize the warning signs of coronary heart disease (CHD) until their health—and their lives—are in jeopardy. According to the American Heart Association, every year more than half a million women die of cardiovascular diseases, which includes diseases of the heart and blood vessels, and stroke. Since 1984, more women have died of cardiovascular diseases than men.
Coronary heart disease (CHD), also known as coronary artery disease (CAD) and ischemic heart disease, is a disease of the heart's blood vessels that, if untreated, can cause heart attacks. Like any muscle, the heart needs a constant supply of oxygen and nutrients that are carried to it by the blood in the coronary arteries. When the coronary arteries become narrowed or clogged and cannot supply enough blood to the heart, the result is CHD.
Heart attack and stroke are common results of conditions that restrict or stop the blood flow to the heart or brain. At any given age, men have a greater risk of heart attack than women, but women are only half as likely as men to survive a heart attack, and more likely to have a second attack.
African-American women are more likely to die of CHD than Caucasian women, perhaps because they are more likely to have more risk factors, including high blood pressure (hypertension), diabetes, obesity and smoking, and are more likely to receive poorer health care than Caucasian women. For example, in 2001, the overall CHD death rate (per 100,000 women) was 176.7 for black women compared to 137.4 for white women and 138.4 for Hispanic women. Heart disease risk is also higher among Mexican Americans, Native Americans and native Hawaiians. This may be partly due to higher rates of obesity and diabetes in these groups.
Coronary heart disease starts with atherosclerosis, a process in which fatty substances build up inside the walls of blood vessels. Blood components also stick on the surface inside vessel walls making the vessels narrower and "hardened," and eventually less flexible. The buildup, or "plaque," may also break apart, which can further limit blood flow. The buildup and narrowing proceed gradually and result in decreasing blood flow, followed by CHD symptoms.
When blood flows more slowly at the site of narrowing, it can be come "sticky" and eventually form a clot. This blood clot can narrow the opening of the artery even further, which can reduce blood flow to the heart, leading to chest pain, or angina. If blood flow is nearly or completely blocked, a heart attack can occur, leading to the death of muscle cells in the heart. Because the cells cannot be replaced, the result is permanent heart damage. Each year, up to half a million American women suffer heart attacks, an all-too-frequent outcome of CHD.
Your risk of developing heart disease increases as you grow older; however, updated 2007 guidelines from the American Heart Association point out that a woman's risk of heart disease develops over her entire lifetime.
Prior to menopause, estrogen is thought to provide some protection to women against heart disease. (Premenopausal women who have diabetes or who smoke are not adequately protected by estrogen, as diabetes and smoking are major risk factors for heart disease.)
Estrogen works to keep a woman's arteries free from atherosclerotic plaque (the buildup of fatty substances cholesterol, cellular waste and other material) partly by improving the ratio of LDL (low-density lipoprotein) and HDL (high-density lipoprotein) cholesterol. Estrogen increases the amount of HDL cholesterol, which helps clear LDL cholesterol from the bloodstream, the type of cholesterol that contributes to plaque buildup in the arteries. LDL cholesterol is a major cause of CHD, according to the National Cholesterol Education Program (NCEP) of the National Heart, Lung, and Blood Institute (NHLBI).
However, taking supplemental estrogen after menopause won't reduce your risk of cardiovascular events. To the contrary, research shows that certain forms of hormone therapy slightly increase a postmenopausal woman's risk of heart attack and stroke.
Risk Factors for Heart DiseaseOver the last two decades, researchers have unearthed many risk factors for developing cardiovascular diseases. These include:
Smoking. Smoking accelerates the development of atherosclerosis by constricting blood vessels, accelerating the formation of blood clots and restricting the amount of oxygen the blood supplies. Smokers who have heart attacks and strokes are more likely to die from them.
High cholesterol levels. According to the National Cholesterol Education Program (NCEP), elevated LDL cholesterol is a major cause of coronary heart disease. That's why the NCEP panel recommends aggressive treatment. Treatment may include lifestyle changes, such as exercising more and reducing the amount of saturated fat in your diet, and medication. A combination of approaches is typically recommended.
Optimal cholesterol levels for healthy women are:
Total cholesterol: less than 200 mg/dL
HDL cholesterol: above 60 mg/dL. This range is considered to be protective against heart disease, while levels less than 40 mg/dL are considered a major risk factor for developing heart disease.
LDL cholesterol: less than 100 mg/dL
Triglycerides: less than 150 mg/dL
High blood pressure (hypertension). When the heart works too hard to pump blood through the body, the intensity can damage the walls of the arteries of the heart and body.
A blood pressure reading records a systolic blood pressure—the highest pressure measured when the heart contracts with each beat, and a diastolic blood pressure—the lowest pressure measured in the arteries when the heart relaxes between beats. Optimal blood pressure is less than 120/80mm hg, read "120 over 80." Hypertension—high blood pressure—is defined as systolic pressure greater than or equal to 140 mm hg or diastolic pressure greater than or equal to 90 mm hg.
There is another category called "prehypertension" you should be aware of. This designation is made when the systolic pressure is 120 to139, or diastolic pressure is 80 to 89, and means you have a significant risk of developing high blood pressure, or hypertension.
Diabetes. Having diabetes poses as great a risk for having a heart attack in 10 years as heart disease itself, according to NHLBI. In fact, cardiovascular disease is the leading cause of diabetes-related deaths. People with diabetes who have not yet had a heart attack have the same risk of future heart attack as someone with known coronary heart disease. Because their risk of heart attack is so high, NHLBI recommends that people with diabetes be treated aggressively with LDL-cholesterol lowering medication and carefully manage their blood sugar to reduce their cardiovascular risk.
Age. Generally, women over age 55 and men over age 45 are at greatest risk for developing atherosclerosis. The risk of cardiovascular events increases with age.
Family history. Family history is one of the biggest risk factors overall for atherosclerosis. Your risk is greater if your father or brother was diagnosed before age 55, if your mother or sister was diagnosed before age 65, or if you have a sibling with early coronary disease.
Obesity. Overweight women are much more likely to develop heart-related problems, even if they have no other risk factors. Excess body weight in women is linked with coronary heart disease, stroke, congestive heart failure and death from heart-related causes.
Inactivity. Not exercising contributes directly to heart-related problems and increases the likelihood that you'll develop other risk factors, such as high blood pressure and diabetes.
Metabolic syndrome. This deadly quartet of abdominal obesity, high blood pressure, glucose intolerance (or pre-diabetes) and abnormal cholesterol is associated with a markedly increased risk of cardiovascular disease.
Homocysteine. Homocysteine is an amino acid normally found in the body. Studies suggest that high blood levels of this substance may increase the risk of heart disease, stroke and peripheral vascular disease.
C-Reactive protein (CRP), a high blood level of CRP, a sign of inflammation, may mean that the walls of the arteries in your heart are inflamed, which may raise your heart disease risk.
A blood test called the high sensitivity C-reactive protein blood test (hs-CRP) is now widely available. Most studies show that in healthy people, the higher the hs-CRP levels, the higher the risk of developing a future heart attack. In fact, scientific studies have found that the risk for heart attack in people in the upper third of hs-CRP levels is twice that of those with hs-CRP levels in the lower third. Recent studies also found a link between hs-CRP to sudden cardiac death and peripheral arterial disease.
According to the American Heart Association, numerous studies have examined whether hs-CRP can predict recurrent cardiovascular disease and stroke and death in various settings. High levels of hs-CRP consistently predict new coronary events in people with unstable angina and acute myocardial infarction (heart attack). Higher hs-CRP levels are also associated with lower survival rate in these people. Many studies suggested that after adjusting for other prognostic factors, hs-CRP was still useful as a risk predictor.
It is not yet known whether specific interventions will benefit those who have high hs-CRP, however aspirin therapy and cholesterol-lowering drugs might be helpful in these individuals.
The American Heart Association and the U.S. Centers for Disease Control and Prevention issued new guidelines for the blood test in January 2003. The guidelines recommend limiting the use of the CRP test as a discretionary tool for evaluating people of moderate risk, and not as a means of screening the entire adult population, as insufficient scientific evidence supports widespread use at this time.
Stress. Although stress has been implicated in the development of atherosclerosis, its exact relationship to heart disease has not been determined. Regular exercise can reduce stress and improve your mood.
Postmenopausal status. Your risk of developing atherosclerosis and heart disease increases once you reach menopause. Prior to menopause, women are mainly protected from heart disease by estrogen, the reproductive hormone produced by the ovaries. Among its many roles, estrogen helps keep arteries free from plaque by improving the ratio of LDL (low-density lipoprotein) and HDL (high-density lipoprotein) cholesterol. It also increases the amount of HDL cholesterol, which helps clear arteries of LDL cholesterol—the kind that most contributes to plaque build up.
Heart Problems Commonly Experienced by WomenThe following are common heart problems in women. If you experience any of the symptoms described below, contact your health care professional for an evaluation:
Angina. If clogged arteries prevent enough oxygen-carrying blood from reaching your heart, the heart may respond with pain called angina pectoris. Episodes of angina occur when the heart's need for oxygen increases beyond the oxygen available from the blood nourishing the heart. Silent angina occurs when the same inadequate blood supply causes no symptoms.
Physical exertion is the most common trigger for angina. Other triggers can be emotional stress, extreme cold or heat, heavy meals, alcohol and cigarette smoking. The pain is a pressing or squeezing pain, usually felt in the chest or sometimes in the shoulders, arms, neck, jaws or back.
Angina suggests that coronary heart disease exists. People with angina have an increased risk of heart attack compared with those who have no symptoms. When the pattern of angina changes—if episodes become more frequent, last longer or occur without exercise—your risk of heart attack in subsequent days or weeks is much higher and you should see your health care professional immediately.
If you have angina, learn its pattern—what cause an angina attack, what it feels like, how long episodes usually last and whether medication relieves the attack. Angina is usually relieved in a few minutes by resting or taking prescribed angina medicine, such as nitroglycerin.
Episodes of angina seldom cause permanent damage to heart muscle.
Heart attack pain may be similar to angina, but the symptoms of angina quickly disappear with rest. Heart attack pain, however, usually persists despite resting or taking nitroglycerin and should be evaluated immediately. Like angina, heart attack pain can be a pressure or tightness in chest, arms, back or neck. Often symptoms include shortness of breath, sweating, nausea, vomiting or dizziness. A heart attack is an emergency. A delay in treatment could mean more of the heart muscle tissue is permanently damaged. If you think you're having a heart attack, take an aspirin (which reduces blood clotting) and get medical help immediately.
Silent ischemia. Sometimes atherosclerosis causes no symptoms. Silent ischemia is a condition caused by atherosclerosis, but isn't associated with the chest pain or other symptoms common to other types of heart conditions. This condition occurs when arteries with atherosclerosis can't deliver enough blood to the heart. An electrocardiogram (EKG or ECG), a measurement of electrical impulses produced by the heart, may indicate silent ischemia. However, without a heart checkup, a woman may never know that she has ischemia. This is why regular screening and checkups, particularly among women with heart disease risk factors such as diabetes, hypertension or a family history, are so important. People with diabetes are especially at risk for this condition because diabetes can cause nerve endings or "pain sensors" to be less sensitive, resulting in ischemia without accompanying pain.
Heart attack. When the blood supply to the heart is cut off completely, the result is a heart attack. It can cause permanent damage to the heart muscle if blood flow is not restored as fast as possible. Typically, chest pain caused by a heart attack may be accompanied by discomfort in other areas of the upper body, indigestion, nausea, weakness and sweating. However, heart attack symptoms vary and may be considerably milder. According to the American Heart Association, women are somewhat more likely than men to experience some of the symptoms other than chest pain, particularly shortness of breath, nausea/vomiting, and back or jaw pain.
Symptoms that indicate your heart is in danger may be present for months or years before a heart attack occurs. Persistent unusual symptoms—shortness of breath, nausea, great fatigue, angina/chest pain, fainting spells and gas-like discomfort—may be red flags for heart disease. Discuss such symptoms with your health care professional, even if the symptoms come and go.
If you are at high risk for a heart attack, it is a good idea to develop an action plan with your health care professional in case one occurs. This might include:
Keeping a list of all medications and how often you take each one with you. Also give a copy to a friend or family member who might be involved with your care if you're taken to the hospital. This list provides valuable information to the emergency department staff.
Keeping a small-sized copy of your EKG in your wallet.
Knowing who should be notified in case of an emergency.
Cardiac syndrome X, or microvascular disease, is characterized by chest pain or ischemia without evidence of blockage in the large coronary arteries. Women are at higher risk than men for this condition. Syndrome X may be caused when the small blood vessels in the heart don't expand enough. Postmenopausal women and women who have had surgical menopause are at risk for experiencing symptoms of syndrome X because their declining estrogen levels may affect the small blood vessels in their hearts.
Because this condition is a small vessel disease, it can't be seen on an angiogram (an x-ray with dye that identifies blockages in the blood vessels). Special imaging tests, such as PET scanning or MRI, may help with the diagnosis in the future. Today, however, syndrome X is usually a diagnosis of exclusion—meaning you may be diagnosed with this condition after tests provide no other cause for the chest pain. Some health care professionals use the same tests used to diagnose CAD, such as an EKG, echocardiography, or coronary angiography. Many women with syndrome X have no risk factors and are otherwise healthy.
Medications commonly used to treat heart conditions may help to relieve pain caused by Syndrome X. The prognosis is generally excellent, but the symptoms can be debilitating.
Cardiac arrhythmias. The normal cardiac rhythm is called "sinus rhythm" and the normal heart rate is 60-100 beats per minute. An arrhythmia occurs when the heart beats irregularly or abnormally slow (bradycardia) or fast (tachycardia). While many arrhythmias don't cause symptoms, some cause chest pain, dizziness, fainting and shortness of breath. Atherosclerosis, angina, valvular heart disease, weakened heart muscle (i.e., cardiomyopathy), blood clots, thyroid abnormalities or heart attack can cause this condition to develop.
Medications can help stabilize heart rhythms. Abstaining from caffeine, alcohol and cigarette smoking can also help. Pacemakers are often recommended to correct a slow heart rhythm.
Assessing Your Own Risk of Heart DiseaseBecause heart disease and its risk factors can be silent for so long, often with few symptoms until the disease is well underway, it's important to know your personal risk factors. That includes your knowing your family health history and your cholesterol and blood pressure levels. Two major studies published in the summer of 2003 found that nearly everyone who dies of heart disease, including heart attacks, had at least one or more of the conventional heart disease risk factors: smoking, diabetes, high blood pressure and high cholesterol.
A simple heart disease risk assessment tool based on the Framingham Risk Model can be found online at It estimates your 10-year risk of having a heart attack or dying of coronary heart disease based on your answers to questions about your personal risk factors. Your risk, whether very high, high, moderate or low, determines what steps you should take to reduce that risk, including whether or not you should be put on medication.
No matter what your age, if you suspect you have heart disease or are at risk of heart disease, talk to your health care professional about diagnostic tests such as an exercise echocardiogram or a nuclear stress test.

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