The cardiac pacemaker prevents the heart rate from slowing down too far. Certain disorders of the system providing the electrical impulses for the heart’s rhythm and the cardiac conduction system, for example sick sinus syndrome, AV heart block, or bradyarrhythmia, may make it necessary for a cardiac pacemaker to be implanted. The pacemaker is inserted under local anaesthetic beneath the skin of the chest. The electrodes are pushed through veins into the heart where they are then secured in the appropriate chambers. Cardiac pacemakers stimulate the heart only when this is required in order to stop the heart rate falling below a preset limit. As long as the heart is beating fast enough of its own accord, the pacemaker monitors the heart’s natural electrical activity from one beat to the next. As a rule, it works without the wearer noticing anything at all. Cardiac pacemaker devices can be programmed via a special computer to meet the various individual needs of patients. Routine surveillance checks take place every six months.