A cross section of the heart.
Before 1900, very few people died of heart disease. Since then, heart disease has become the number one killer in the world. The age of technology has made life easier and made people more prone to heart disease.
Before the Industrial Revolution, most people made their living through some sort of manual labour. Walking was the major means of transportation. Laundry was scrubbed and wrung by hand. Stairs were climbed, carpets were beaten, and butter was churned.
With the arrival of automation, life became less strenuous. Most manual labour was either replaced or assisted by machinery. Automobiles, washing machines, elevators, and vacuum cleaners became commonplace. Modern conveniences made physical activity unnecessary.
Along with the change in lifestyle came a change in diet. Machines were built to homogenize milk, process cheese, churn butter, and make ice cream. Previously, such high-fat treats had to be made by hand. Fried foods, like potato chips, hamburgers, and french fries, became staples in many diets.
The combination of a sedentary lifestyle and a rich diet led to an increase in clogged blood vessels, heart attacks, and strokes. Heart disease became commonplace. The rate of heart disease increased so sharply between 1940 and 1967 that the World Health Organization called it the world’s most serious epidemic.
Medical science immediately went to work studying the disease and searching out its causes and cures. In 1948, a thirty-year study began in Framingham, Massachusetts. Known as the Framingham Study, the investigation involved 5127 people aged 30 to 62 who showed no signs of heart disease. Every two years, the participants underwent a complete physical examination. The study lasted thirty years and provided priceless profile information for predicting heart disease.
Today, the causes of heart disease are known. To a certain extent, so are the cures. The field of cardiology has grown tremendously to meet the demands of the disease. Through the years, tools and techniques for treating heart disease have also evolved to meet the increased need. Many of the milestones in cardiology once seemed unreachable. Who knows what the future may hold?
In some cases, heart disease may be so severe that the patient may not survive the wait for a donor heart. Medical scientists have developed electronic devices such as defibrillators, pacemakers, and artificial heart models that can keep the patient alive until a heart becomes available.
One of the best known devices is the “Jarvik-7” artificial heart, named for its designer Robert K. Jarvik, an American physician. Designed to function like the natural heart, the Jarvik-7 has two pumps (like the ventricles), each with a disk-shaped mechanism that pushes the blood from the inlet valve to the outlet valve.
The action of the artificial heart is entirely similar to the action of the natural heart. There is, however, one huge difference : the natural heart is living muscle, while the artificial heart is plastic, aluminum, and Dacron polyester.
As a result, the artificial heart needs some external source of “life”. An external power system energises and regulates the pump through a system of compressed air hoses that enter the heart through the chest. Since the system is cumbersome and open to infection, the use of an artificial heart is meant to be temporary.
The Jarvik-7 was first used during the early-1980s. However, earlier artificial hearts date back to the mid-1950s. In 1957, a team of scientists, led by Willem Kolff, a Dutch-born physician, tested their model in animals to identify problems.
In 1969, a team led by Denton Cooley of the Texas Heart Institute successfully kept a human patient alive for more than sixty hours with their model. During the years that followed, the notion of a permanent, rather than temporary, implantation began to take hold.
In 1982, a team led by William DeVries of the University of Utah implanted the Jarvik-7 into a patient named Barney Clark. For various medical reasons, a transplant operation was not an option for Clark. Therefore, he was a prime candidate for a permanent artificial heart. He survived with the Jarvik-7 for 112 days.
Since then, development of an improved artificial heart has continued. One possibility is an electrical heart powered by a small wearable battery that does not require any break in the skin. Perhaps, someday, the artificial heart will become a realistic, permanent option for survival.
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