CARDIOLOGY

medical specialty dealing with the diagnosis and treatment of diseases and disorders of the heart. Cardiology first became a specialized field of study when Jean Baptiste de Snac in 1749 published a summary of contemporary knowledge of the heart. This was followed 12 years later by Leopold Auenbrugger's discovery that the condition of the heart can be estimated by the sound returned from tapping on the chest (percussion). Listening to heart sounds became a major part of medical diagnosis after Ren Lannec's invention of the stethoscope in 1816. Much of the development of cardiology during the 19th century consisted of improved diagnostic methods. An important diagnostic advance was Willem Einthoven's invention in 1903 of the electrocardiograph, which measures the heart's electrical activity; by 1915 the basic methods of diagnosis of heart disease, including fluoroscopic studies of the beating heart, were in place. Various advances in diagnostic technology opened up the possibility of surgical correction of many heart problems. Cardiology itself remains a medical, not a surgical, specialty although cardiologists work closely with surgeons in cases of heart surgery. Cardiologists provide the continuing care of heart patients, performing basic studies of heart function and supervising all aspects of therapy, including the administration of drugs to modify heart functions. Much of the development of cardiac medicine in the second half of the 20th century has been in the field of heart surgery. Major advances in this field have included the routine repair of coronary artery disease, one of the major causes of heart attacks; the first human heart transplant, performed by Christiaan Barnard of South Africa in 1967; and the development of a permanently functioning, surgically implanted artificial heart by a research team at the University of Utah, first used in 1982.