When you have a rhythm problem with your heart (usually when it beats too slowly or if both sides of your heart don't beat together), you may need a pacemaker.
A pacemaker has two parts:
a pulse generator (battery) that produces electrical pulses
lead wires or electrodes (insulated, flexible wires that carry the electrical impulses to the heart). You may have one, two or sometimes three lead wires.
The generator and the electrode are covered with materials compatible with the human body. The coverings also protect the device from your body fluids.
Implanting a pacemaker
If you receive a pacemaker, it will most likely be implanted in one of two ways:
transvenous (in a vein). The electrode lead is put into a vein and threaded through to a chamber in the heart. The pulse generator is usually implanted below the collarbone. This is the most common way of implanting a pacemaker.
epicardial (outside of the heart). The lead is attached directly to the outside of the heart.
Your doctor will recommend which way the pacemaker will be implanted based on your age, lifestyle and medical condition.