One of the important advances in cardiology is the artificial pacemaker used to electrically initiate a normal heartbeat when the patient's own pacemaker is defective (see arrhythmia); it may be surgically implanted in the patient's body. Similarly, an internal defibrillator may be implanted to deliver an electrical shock to the heart in order to stop certain forms of rapid heart rhythm disturbances. Another familiar tool of the cardiologist is the electrocardiograph (EKG), which is used to detect abnormalities that are not evident from a physical examination (see electrocardiography).
One of the most important advances in heart surgery during the 1960s was the transplantation of the healthy heart immediately after the death of an individual (the donor) to a recipient suffering from incurable heart disease (see transplantation, medical). In the 1980s new advances in the design and construction of an artificial heart—both the entire organ and such parts as the valves and large blood vessels—showed some promise in treating cardiovascular disease (see heart, artificial), but the limited success that has characterized artificial heart implantation thus far has led many experts to question the efficacy of such measures. Although the artificial heart has often been used as a temporary measure until a permanent human donor heart can be located, a number of recipients have not fared well, even for a limited duration. In addition, it is often unclear how long the recipient will have to wait for a donor. Proponents of the artificial heart hope that technological advances will allow the permanent replacement of human hearts with artificial ones.