HISTORY IN HEART RESEARCH

Early beliefs about the heart. In ancient times, many people believed that the heart had special importance. For example, the Chinese thought that each emotion originated in a certain organ and that happiness dwelt in the heart. Chinese physicians diagnosed many illnesses and prescribed treatment by taking the pulse at the wrist. The ancient Egyptians considered the heart to be the source of intelligence and emotion. The ancient Greeks learned from battlefield injuries and animal sacrifices that the heart was a beating organ. In the A.D. 100's, the Greek physician Galen developed the first medical theories based on scientific experiments. Galen observed the heartbeat and realized that the heart put blood in motion. But he thought that the heart's right ventricle forced blood into the left ventricle through holes in the septum. Galen also believed that the liver converted food into blood, which then flowed through the body and was used up.

Discovery of circulation. Doctors accepted Galen's theories--in spite of the many errors--until the 1500's. In the mid-1500's, a Flemish-born physician named Andreas Vesalius described veins and arteries. He also showed that no holes exist between the heart's chambers. Also in the 1500's, Michael Servetus, a Spanish physician and theologian, reasoned that blood flows between the heart and lungs. But his studies were not publicized because of his unpopular religious beliefs. The theory of blood circulation was first published in 1628, by William Harvey, an English physician. His work became the basis of modern research on the heart and blood vessels. Harvey showed that the heart works like a pump. He described how blood flows from the heart to the lungs, back to the heart, out to the body, and back to the heart. Harvey believed that small blood vessels called capillaries connect arteries and veins. The idea of capillaries had been proposed in the 1500's by an Italian anatomist named Andrea Cesalpino.

Marcello Malpighi, an Italian physician, proved their existence in 1661. In the early 1700's, Stephen Hales, an English clergyman and scientist, became the first person to measure blood pressure. He placed a glass tube in a horse's artery after breaking through the animal's skin. Hales published the result of this experiment in 1733. Invention of new medical instruments. During the 1800's, many inventions expanded doctors' knowledge of the heart and helped in their diagnosis and treatment of heart problems. In 1816, a French physician named Rene Laennec invented the stethoscope, which enabled doctors to listen to sounds of the heart and other organs. In 1880, Samuel Siegfried von Basch, a Viennese physician, developed the sphygmomanometer, an instrument to measure blood pressure without breaking the skin. Russian physician Nikolai Korotkoff used a stethoscope in 1905 to take the pulse while measuring blood pressure, thus recording systolic and diastolic blood pressure.

Doctors still use this technique. In 1903, Willem Einthoven, a Dutch physiologist, invented the string galvanometer, a device to measure minute electrical currents generated by the activity of the heart, and so developed the basis of the electrocardiograph. By the 1920's, the electrocardiograph had become the chief diagnostic tool in cardiology. Development of heart surgery. An American cardiologist named James B. Herrick made the first diagnosis of a heart attack in 1912. In 1938, Robert E. Gross, an American surgeon, performed the first successful repair of a congenital heart defect. Gross sewed the hole in the artery of a child suffering from patent ductus arteriosus. In 1944, Helen Brooke Taussig and Alfred Blalock, two American physicians, developed an operation to help correct abnormal circulation of blue babies. In 1952, American surgeon Charles Hufnagel operated on a beating heart and implanted the first artificial heart valve.