The Cardiovascular System - Ailments: what can go wrong with the cardiovascular system
Diseases that affect the heart and the cardiovascular system are among the most serious health problems facing Americans. In fact, cardiovascular or heart disease is the leading cause of death in the United States. The disease does not recognize gender, race, or age: it afflicts all people equally. According to statistics, almost 70 million people in the country suffer from some type of cardiovascular disease. Each year, more than one million of those people die.
The following are just a few of the many diseases and disorders that can impair the cardiovascular system or its parts.
The word anemia literally means "lack of blood." It is a condition that results when the number of red blood cells or the amount of hemoglobin is reduced to a low level and the cells of the body do not receive all the oxygen they need to function and produce energy. Weakness, listlessness, drowsiness, headaches, soreness of the mouth, slight fever, and other discomforts are characteristics of anemia. Scientists have identified more than 400 types of anemia. Common forms of the condition may be brought about by rapid blood loss, the destruction or disease of the bone marrow, or an inadequate amount of iron or the vitamin B 12 in a person's diet.
Anemia (ah-NEE-me-yah): Diseased condition in which there is a deficiency of red blood cells or hemoglobin.
Arteriosclerosis (ar-tir-ee-o-skle-ROW-sis): Diseased condition in which the walls of arteries become thickened and hard, interfering with the circulation of blood.
Atherosclerosis (ath-a-row-skle-ROW-sis): Diseased condition in which fatty material accumulates on the interior walls of arteries, making them narrower.
Hemophilia (hee-muh-FILL-ee-ah): Inherited blood disease in which the blood lacks one or more of the clotting factors, making it difficult to stop bleeding.
Hypertension (hi-per-TEN-shun): High blood pressure.
Leukemia (loo-KEE-mee-ah): Type of cancer that affects the blood-forming tissues and organs, causing them to flood the bloodstream and lymphatic system with immature and abnormal white blood cells.
Sickle cell anemia (SICK-el cell ah-NEE-me-yah): Inherited blood disorder in which red blood cells are sickle-shaped instead of round because of defective hemoglobin molecules.
Atherosclerosis is a type of arteriosclerosis, a general term for hardening of the arteries. Atherosclerosis is a condition in which fatty material and other substances accumulate on and in the walls of large arteries, impairing the flow of blood.
Cholesterol, a fatlike substance produced by the liver, is an essential part of cell membranes and body chemicals. Normally, the body produces all the cholesterol it needs. Eating foods high in saturated fats (found mostly in animal products such as egg yolks, fatty meats, and whole milk dairy products) can cause an increase in blood cholesterol levels. The excess cholesterol not taken up by the cells accumulates on the walls of arteries. There it combines with fatty materials, cellular waste products, calcium, and fibrin to form a waxy buildup known as plaque, which can either partially or totally obstruct blood flow.
Coronary heart disease (also known as coronary artery disease) arises when atherosclerosis occurs in the coronary (heart) arteries. When the blood flow in these arteries is restricted, the heart muscles do not receive the proper amount of blood and oxygen. Chest pain or pressure, called angina, may occur. If the blood flow is blocked, cardiac muscle cells begin to die and a heart attack may result.
If blood flow is blocked in any cerebral (brain) arteries, brain cells quickly begin to die and a stroke may result. Depending on what area of the brain has been affected, a stroke may cause memory loss, speech impairment, paralysis, coma, or death.
Atherosclerosis is a complex condition, and its exact cause is still unknown. However, scientific studies have shown that smoking, diabetes, a diet high in fats and low in fiber, and lack of exercise can all increase the risk of developing atherosclerosis.
Congenital heart disease
Congenital heart disease (sometimes called congenital heart defect) is any defect in the heart or its main blood vessels that is present at birth. Almost 1 out of every 100 infants are born with some sort of heart abnormality. At present, scientists have recognized thirty-five types of defects. Most of these abnormalities or defects obstruct or alter the flow of blood in the heart or the vessels near it. Defects include openings in the septum between the atria or the ventricles, the emergence of the aorta and pulmonary artery out of the same ventricle, the development of only one ventricle, or the formation of only one side of the heart. About half of those people with congenital heart disease require surgery to correct the problem.
A medical milestone occurred on December 3, 1967, when South African surgeon Christiaan Neethling Barnard performed the first human heart transplant. The procedure, in which a fifty-five-year-old man received the heart of a young accident victim, took place at Groote Schuur Hospital in Cape Town, South Africa.
Barnard, born in 1922, had been focusing his attention on various kinds of open-heart surgery since the late 1950s. Soon after, he had begun to experiment with surgical transplantation. By the late 1960s, he was ready to perform a human heart transplant. All he needed were a proper patient and a donor.
That patient soon turned out to be Louis Washansky, a wholesale grocer who had suffered a series of heart attacks over the previous seven years. Washansky, admitted to the hospital in November 1967, was dying of a failing heart. Doctors estimated he had only weeks to live.
On December 2, twenty-five-year-old Denise Darvall was involved in a severe auto accident. When she was carried into the hospital's emergency room, her brain was dead, but her heart was still beating. Barnard asked her parents if they would donate her heart and they agreed.
The following day, assisted by a team of thirty associates, Barnard placed Darvall's heart into Washansky's chest. Within a few days, Washansky was well enough to sit up in bed. However, to prevent his body from rejecting the new organ, Washansky was given medication that suppressed his immune system. Although the medication worked, it also lowered his body's resistance to infection. Eighteen days after the surgery, Washansky died of pneumonia.
In January 1968, Barnard tried again, this time transplanting the heart of a twenty-four-year-old stroke victim into Philip Blaiberg, a fifty-eight-yearold retired dentist. Blaiberg lived for eighteen months after the surgery.
Today, with the development of more effective immunosuppressant drugs (those that hinder the workings of the immune system), transplant patients survive much longer. Three-quarters of heart-transplant patients currently survive five years after the operation.
Murmurs are abnormal, extra heart sounds made by the blood moving through the heart and its valves. Generally, blood flows smoothly and silently through the heart. The only sounds a physician normally hears through a stethoscope are the "lub-dup" sounds created by the closing of the heart valves.
Heart murmurs that are very faint, intermittent, and do not affect a person's health are called "innocent" heart murmurs. They may be caused by the failure of a heart valve to open or close completely. In the healthy hearts of children (or of the elderly), innocent heart murmurs may exist because the heart walls are relatively thin. As blood rushes through, the walls vibrate, creating extra sounds. Innocent heart murmurs in children usually disappear with age.
Murmurs that are caused by severe heart defects, however, are louder and continual. They can bring about chest pain, shortness of breath, dizziness, and, in extreme cases, death. Surgery is often required to correct severely damaged or diseased valves.
Hemophilia is an inherited blood disease in which the blood lacks one or more of the clotting factors. Because of this, the blood is unable to form a clot, and even a small cut can result in prolonged bleeding and death. Commonly called "bleeder's disease," hemophilia principally affects males. When hemophiliacs (people afflicted with hemophilia) suffer a trauma and begin to bleed, they are given a transfusion of fresh plasma or an injection of the clotting factor they lack.
In December 1998, a team of doctors from the U.S. and Europe announced a possible breakthrough technique to reduce the risk of rejection in heart-transplant patients.
Currently, when patients are given new hearts, they are also given drugs, called immunosuppressants, to prevent their immune systems from developing antibodies that would attack the new organs. Unfortunately, these drugs also weaken their immune systems, allowing infections to develop.
Under the new technique, called photophoresis, light is used to destroy cells that prompt the body to reject the transplanted organ. First, blood is pumped from the patient's body. Then the white blood cells in that blood are treated with ultraviolet A light and methoxsalen (a chemical that makes the cells hypersensitive to that type of light). Afterward, the blood is returned to the patient's body.
Of those patients who received the light technique plus immunosuppressant drugs, 81 percent experienced only one episode of rejection. Of those patients receiving only the drugs, the rate was just 52 percent.
The new technique has not yet shown it can increase a patient's long-term chance of survival, but it has helped limit the amount of drugs needed to fight rejection.
Hypertension is high blood pressure. It is normal for blood pressure to be elevated for brief periods because of exercise, emotional stress, or a fever. Consistent arterial blood pressure measuring 140/90 or higher, however, is hypertension. The condition, the most common one affecting the cardiovascular system, is a serious one. Although it shows no symptoms, hypertension should be treated. If left unchecked, it can lead to atherosclerosis, heart attack, stroke, or kidney damage.
Hypertension most often strikes African Americans, middle-aged and elderly people, obese people, heavy alcohol drinkers, and people suffering from diabetes or kidney disease. Scientists do not know the cause for 90 to 95 percent of hypertension cases. However, studies have shown that reducing salt and fat intake, losing weight, quitting smoking, reducing alcohol consumption, and exercising regularly all combine to reduce blood pressure. Numerous drugs have also been developed to treat hypertension.
Leukemia (pronounced loo-KEE-mee-ah) is a type of cancer that affects the blood-forming tissues and organs, mainly the bone marrow, lymph nodes, and spleen. The disorder causes these blood-forming tissues and organs to flood the bloodstream and lymphatic system with immature and abnormal white blood cells. The overproduction of white blood cells causes a crowding-out of red blood cells and platelets.
Infections develop because these useless white blood cells have no infection-fighting ability. Anemia, easy bruising, and hemorrhaging (bleeding without clotting) also occur because of the lack of red blood cells and platelets. Leukemia is further marked by high fever and continual weakness.
Although ten times as many adults as children are stricken with the disease, leukemia is the number one disease killer of children. There are many types of leukemia, but no one cause of the disease is known. Scientists believe genetic abnormalities, exposure to toxic chemicals, and overexposure to X rays or other radioactive materials may play a part in the development of leukemia.
Chemotherapy—drug therapy to poison and destroy the abnormal cells—is effective against some types of leukemia, especially in children. Blood transfusions and bone marrow transplants have also proven effective in certain cases. With the best treatment, almost 75 percent of children suffering from leukemia survive.
Sickle cell anemia
Sickle cell anemia is an inherited blood disorder in which defective hemoglobin molecules tend to stick to one another in a red blood cell, forming strands of hemoglobin. Red blood cells that contain these strands become rigid, sticky, and crescent or sickle shaped.
These sickle-shaped cells do not last as long as normal red blood cells. They die quickly, leaving a shortage of red blood cells in the body. Anemia then develops. Sickle cells cause further problems by not fitting well through small blood vessels. They become trapped, forming a blockage that prevents normal blood flow. Tissues and organs deprived of oxygenated blood and nutrients begin to deteriorate. Acute pain develops. Over time, damage to the kidneys, lungs, liver, and central nervous and immune systems may be considerable. Severe complications may even lead to strokes and death. Those people who die from sickle cell anemia often do so before the age of thirty.
Sickle cell anemia primarily affects people with African, Mediterranean, Middle Eastern, and Indian ancestry. In the United States, the disease occurs
in about 1 out of every 500 African American births and 1 out of every 1,000 to 1,400 Hispanic American births.
There is no known cure for the disease. Painkillers, antibiotics (to fight infections), blood transfusions (to boost red blood cell count), and oxygen are treatments given to alleviate symptoms and decrease the chance of complication. Though risky, bone marrow transplants have proven effective for certain children who have been severely affected by sickle cell anemia.