Cardiology is the study of the heart and its diseases. the medical study of the heart. Medical specialty dealing with heart diseases and disorders. It began with the 1749 publication by Jean Baptiste de Sénac of contemporary knowledge of the heart. Diagnostic methods improved in the 19th century, and in 1905 the electrocardiograph was invented. The 20th century saw many surgical advances in cardiology, including heart transplants and the use of artificial hearts. Current diagnostic methods include chest percussion (tapping) and auscultation, electrocardiography, and echocardiography (see ultrasound). Cardiologists provide continuing care of heart patients, doing basic heart-function studies, supervising therapy, including drug therapy, and working closely with heart surgeons