The rapid pacing is not felt by the patient but the electrical shock, if used, is felt as a strong jolt in the chest. Some people are now studying the use of these devices for the treatment of less dangerous heart rhythms as well, such as atrial fibrillation. The device is implanted in an operating room under deep sedation. The procedure typically takes two to three hours and patients are discharged from the hospital on the following day. Older devices were implanted in the abdominal wall but the newer, smaller devices are implanted under the collar bone, similar to a standard pacemaker.
Leads run from the device through a vein into the heart.
These leads report the heart's electrical activity back to the device and deliver the electrical therapy, if needed. These devices can also act like a standard pacemaker and pace the heart if it ever beats too slow. Like a pacemaker, these devices must be continually monitored. A device placed on the skin overlying the device can find out about how the device has been programmed, determine the status of the battery, see if any pacing or shocks were given and the heart rhythm that was treated. The programming of the device can be modified as needed to best suit the patient's needs.