Congenital Disorders
Congenital disorders usually arise during the first trimester of pregnancy. They appear to be
linked to genetic, environmental, and behavioral factors, such as maternal use of cocaine or excessive amounts of alcohol during pregnancy. At least 35 types of defects have been recognized. They include blockages that hinder blood flow, holes that allow blood to flow in the wrong direction, malformed or missing heart valves, and faulty connections between the heart and great vessels. These problems increase the heart's work and interfere with normal growth of the child. One group of defects allows oxygen-depleted or "blue" blood to flow to the body without passing through the lungs. Patients with this condition, called cyanosis, are referred to as "blue babies" because their skin appears blue-tinged.
In the United States about 32,000 congenital heart defects occur each year. Many of these defects can be diagnosed before birth. Occasionally they will clear up spontaneously after the child is born. In the remaining cases medical or surgical treatment usually allows the child to lead a normal life.
Prevention
Researchers have identified a number of risk factors that contribute to cardiovascular disease. These include increasing age, male gender, a family history of cardiovascular disease, high blood pressure, and high blood cholesterol levels, as well as certain lifestyle factors, such as diet, cigarette smoking, and lack of exercise. Other possible contributing factors include diabetes, obesity, and stress. Some of these factors are not alterable, but others may be modified or eliminated through behavioral changes. Because cigarette smoking contributes to 20% of cardiovascular deaths, cessation of smoking is extremely important in preventing cardiovascular disease. By adopting a low-fat diet and participating in regular physical activity, the risk can be further reduced.
Diagnosis
The patient's medical history and the results of a clinical examination are important in diagnosing cardiovascular disease. Standard tests include chest X ray examination, electrocardiography, and echocardiography. While being tested, the patient may be asked to exercise on a treadmill or stationary bicycle. In some cases, a CAT scan, positron emission tomography, or magnetic resonance imaging may be necessary. For coronary artery disease and certain other conditions the patient must undergo cardiac catheterization. In this procedure a catheter is inserted into a peripheral artery and passed into the heart. A special dye is then injected so that the cardiovascular structures can be viewed from within.
Treatment Trends
In the United States almost 4.7 million cardiovascular procedures were performed in 1994. These procedures included more than 2,300 heart transplants. Because the number of available donor hearts cannot keep pace with the number of patients who need transplantation, many patients are being kept alive with mechanical cardiac assist devices while they await a suitable donor heart.