Heart Disease page 2: What Can Go Wrong

With the basic features of the heart and circulatory system in mind, it's easier to sort out the different categories of heart disease.

Ischemic Heart Disease

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This category includes anything obstructing the blood flow. (Ischemia comes from two Greek words meaning “keeping back” and “blood.”) The most common obstruction is atherosclerosis, a buildup of fats and calcium on the interior walls of the coronary arteries. This condition is called coronary artery disease or CAD. Atherosclerosis is a progressive problem that, in some people, begins early in life. It can be the result of genetics, diet, cigarette smoking, high blood pressure, or a combination of some or all of these factors. Obstructed arteries can in turn lead to two of the most common heart disorders: angina pectoris or myocardial infarction (MI).

Angina is chest pain that occurs when the heart receives an inadequate blood supply during periods of increased demand, such as unusual exertion or emotional excitement. During such periods, the coronary arteries ordinarily expand to deliver more blood to the heart muscle. Atherosclerotic arteries, however, gradually become rigid, fail to dilate, and can't meet the demand. Usually angina subsides when the exertion stops; however, some people suffer from angina even when resting.

In the past, treatment of angina in women has typified the controversy about the perception of heart disease as a male problem. All too often doctors have dismissed chest pain in women as something benign, perhaps related to anxiety, and not requiring further testing or diagnostic procedures. As both women and their doctors are educated that chest pain that seems like angina could be heart disease, that problem should diminish. Angina is often the first symptom of more serious heart problems to come, and should not be ignored.

MI, or heart attack, occurs when the blood supply to the heart muscle, or myocardium, is severely reduced or stopped, as when a blood clot becomes lodged in a coronary artery. Deprived of its blood supply, the area of heart muscle served by the blocked artery weakens and dies. The affected area is called an infarct, hence the term “Mycardial infarction.” A heart attack is also called coronary thrombosis (referring to a clot) or coronary occlusion, meaning an obstruction. A heart attack can also be the result of an unexplained temporary spasm of a coronary artery.

Silent or unrecognized MI has been found to be more common in women than men. In the Framingham Heart Study, an ongoing analysis of the health and disease of a large group of people in the town of Framingham, Massachusetts, 35 percent of MIs in women were initially unrecognized, compared with 27 percent in men. Framingham and other studies have also shown that compared with a man, a woman's first heart attack is more likely to be fatal; she will require longer hospitalization after a heart attack; and she is more likely to die in the first year after an attack.

Warning Signs. Everyone, male and female, should be aware of the warning signals of a heart attack. Shortness of breath, fatigue, nausea, and upper abdominal pain have been noted as more common in women than men. The general signs, as listed by the American Heart Association, are:

• Uncomfortable pressure, fullness, squeezing or pain in the center of the chest that lasts more than a few minutes, or goes away and comes back.
• Pain spreading to the shoulders, neck, or arms.
• Chest discomfort with light­headedness, fainting, sweating, nausea, or shortness of breath.

Valvular Heart Disease

Valvular disorders are much more common in women than men. One study, the 1987 National Hospital Discharge Survey, found that 71 percent of patients with aortic or mitral valve disease were women.

Mitral valve prolapse (MVP), the most common valvular heart disease, affects about 5 percent of all women in this country (compared with 3 percent of men). With this condition, the valve between the left atrium and ventricle does not shut tightly, allowing a partial two-way flow called “regurgitation.” The cause of most cases of mitral valve prolapse is thought to be genetic. Symptoms of this can include chest pain, shortness of breath, heart palpitations, fainting, and anxiety or panic attacks. However, since these non-specific symptoms also apply to other conditions, more definitive testing is needed for a diagnosis of MVP.

Other valve disorders can result from rheumatic fever, a disease caused by a bacterial infection. Once thought to be nearly eliminated in this country, rheumatic fever has had something of a comeback in recent years. The most common consequence of rheumatic fever is mitral valve stenosis, a narrowing of the opening of the mitral valve which makes it more difficult for the blood to flow through the valve. The aortic valve can also be affected.

Connective tissue diseases such as Marfan syndrome and systemic lupus erythematosus (SLE) also frequently lead to valvular disorders. Nearly 90 percent of SLE patients are women.

Diseases of the Heart Muscle

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Cardiomyopathy is the term used to describe any disease of the heart muscle. The problem can result from many of the conditions listed above, including heart attack, atherosclerosis, and rheumatic fever. It can also be brought on by high blood pressure which may enlarge the heart. Idiopathic cardiomyopathy is a condition for which no cause is known. In hypertrophic cardiomyopathy, heart muscle tissue grows improperly. Viral cardiomyopathy is caused by certain viruses. Ischemic cardiomyopathy is caused by numerous tiny infarctions in which destruction of heart muscle is too limited to be felt as it occurs, but cumulatively damages the heart. Hypertensive cardiomyopathy is caused by untreated high blood pressure. Preliminary research into these diseases has shown differing patterns in men and women, with men usually afflicted sooner and more severely.

Congestive heart failure occurs when the heart muscle is unable to maintain normal blood flow throughout the body. It can happen when the heart muscle or valves are damaged or the nerves governing the heartbeat are working improperly. It may also result from other diseases such as anemia (a blood deficiency disease), pulmonary emboli (blockages of the pulmonary artery), some infections, rheumatic fever, or thyroid disease. Congestive heart failure can cause swelling in body tissues and a buildup of fluid in the lungs. Swelling, particularly in the legs and ankles, is often an early sign of congestive heart failure. Shortness of breath is another.

Infections of the heart valves and heart lining can result in a condition called bacterial endocarditis. These infections are most often seen in people with structural abnormalities of the heart, valve malfunctions, or artificial valves. Bacterial endocarditis is also seen in injection drug users.

Arrhythmias

Arrhythmias are irregular heartbeats. They are caused by malfunction in the electrical signals that stimulate the heart to beat. Bradycardia is the term for heart rates of less that 60 beats per minute; tachycardia refers to more than 100 beats per minute. Arrhythmias can cause a wide range of symptoms, ranging from a barely perceptible palpitation or skipped beat to collapse and death.

Bradycardia may prevent the heart from pumping enough blood to the body, causing fatigue, light­headedness, loss of consciousness, or even death if the rate becomes so slow that the heart and brain stop working.

In the case of tachycardia, the ventricular chambers of the heart may not have sufficient time to fill with blood, thus reducing the heart's ability to pump properly. Sometimes this is accompanied by chaotic electrical signals in the upper chambers called atrial fibrillations. Tachycardia can result in shortness of breath, chest pain, light­headedness, or loss of consciousness.

Arrhythmias are common, even in healthy people, but they are seen more often in people whose hearts have been damaged by other forms of heart disease such as atherosclerosis, high blood pressure, or scarring from a heart attack. They may also be caused by problems or defects of the nervous system, which delivers the electrical signals to the heart. Certain substances can also cause arrhythmias, including alcohol, cigarettes, cocaine, and even some cardiac medications.

Noncoronary Cardiovascular Disease

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This type of disease occurs in the circulatory system, but not directly in the heart. The two most common conditions in this category are hypertension (high blood pressure) and stroke.

THE “FEMALE” HEART DISEASE

By a 2 to 1 margin, diseases of the heart's aortic and mitral valves develop more frequently in women. Often of genetic origin, the diseases are also associated with connective tissue disorders found primarily in female patients. Positioned at the portal between the left atrium and ventricle, the mitral valve is particularly vulnerable to a condition called prolapse. Instead of sealing the portal between the two chambers when the ventricle contracts, a prolapsed mitral valve is forced backward into the atrium, allowing some of the blood that has just left there to return. As a result, each heartbeat pushes a little less blood through the aorta and onward to the rest of the body; and the heart must work just a little bit harder to keep the body adequately supplied. The culprits in this condition are stretched and weakened papillary muscles, which ordinarily hold the lips of the valve tightly in place. The mitral valve plays a role in other problems as well. In the condition called mitral valve stenosis, the opening narrows, hindering the normal progress of blood from the atrium to the ventricle. The problem is an aftermath of rheumatic fever.

Hypertension. Blood pressure is the measure of the force of blood traveling through the circulatory system. As blood flows through the arteries and arterioles (small arteries), their walls contract or expand, changing the resistance to blood flow. Contraction increases the resistance, reducing blood flow, increasing blood pressure, and thereby causing the heart to work harder.

Nearly everyone is familiar with the blood pressure cuff, called a sphygmomanometer, which is strapped on during a physical examination to measure blood pressure. It takes two measures: the systolic pressure, the first number, is the force of blood flow when the heart beats; the diastolic pressure, the second number, is the pressure between heartbeats when the heart is at rest. Blood pressure goes up with age and there is a wide variation in what is considered normal, but generally a reading higher than 140/90 means high blood pressure, or hypertension.

Men are more likely to have high blood pressure than women, but African­American women have higher levels than any other group. One study that measured blood pressure in 35- to 74-year-old women found that 20 percent of white women had high blood pressure, compared with nearly 40 percent of African­American women.

The cause of most hypertension is unknown, although overweight and excessive salt in the diet seem to be contributing factors. A genetic component is also likely. Although hypertension itself is not often listed as a cause of death, it can lead to fatal conditions such as heart attack and stroke.

Stroke is a form of cardiovascular disease that affects the arteries leading to the brain. It occurs when one of these arteries bursts or becomes clogged by a blood clot. When the brain is deprived of the oxygen carried by blood, nerve cells in the affected area die. Stroke can cause disabilities, including partial paralysis and loss of speech, memory, or understanding, and frequently proves fatal.

Sometimes strokes are preceded by transient ischemic attacks (TIAs), called little strokes, which occur when an artery leading to the brain is temporarily clogged. These attacks usually last only minutes and leave no residual effects, but may be a sign that a more serious stroke will occur in the days, weeks, or months to come.

Other signs of stroke, as described by the American Heart Association, include:

• Sudden weakness or numbness of the face, arm, or leg on one side of the body.
• Sudden dimness or loss of vision, especially in only one eye.
• Loss of speech, difficulty talking, or difficulty understanding speech.
• Sudden, severe, unexplained headache.
• Unexplained dizziness.

As with hypertension, which is often linked to stroke, African­American women are as much as twice as likely as white women to suffer strokes.

Peripheral vascular disease, a narrowing of the blood vessels in the arms and legs, is another disease of the circulatory system. It is very strongly linked to cigarette smoking and diabetes and is much more common in men than in women.

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