Pacemakers are designed to stimulate the heart muscle when the normal electrical pulses from the heart are insufficient. The standard pacemaker consists of a generator in which is stored the battery and sophisticated electronics.
The first pacemakers were very large and were located outside the body. With time the size of the pacemaker has gradually become smaller as both battery technology and electronics have become miniaturized. The pacemaker is connected to the heart by a pacemaker lead. The lead now is a flexible wire coated in a polyurethane or silicone coating.
Pacemakers fail for 2 main reasons. Either the pacemaker itself or the lead malfunctions. Lead malfunctions usually result from a crack either in the coating or the wire itself. They can also harbor infection which is virtually impossible to irradicate without removing the pacing lead completely from the body.
A new generation of miniature pacemakers have been designed and tested. These pacemakers are the size of a finger nail (see picture1) and are implanted into the right ventricle of the heart by using a long introducing sheath placed from the groin. Early reports have certainly shown that they can be deployed with a low (-ish) complication rate.
Do they have a role to play? Like any new innovation it is usually best to wait for a few months or years before using it. This gives us a chance to see the reliability and complications that are likely to accrue with time. However there are a small number of people who this would genuinely be very useful now. These are patients who have had several previous pacemakers and have extensive scarring on the chest wall making it difficult to place another pacemaker generator under the skin of the patient