What is a Pacemaker & How Does it Work?
If you have a condition called bradycardia, otherwise known as a slow heart beat, you and your doctor may decide an implantable heart device called a pacemaker is the right option for you.
When people refer to a pacemaker, they are actually discussing a pacing system, which includes the pacemaker and leads.
- A pacemaker is the small device that is implanted under the skin, most often below the collarbone on the left or right side of your chest. The pacemaker continuously monitors your heart, and if it detects a slow rhythm problem, it sends out small undetectable electrical signals to correct it.
- Leads are thin, soft, insulated wires about the size of spaghetti noodles. The leads carry the electrical impulse from the pacemaker to your heart and relays information about the heart’s natural activity back to your pacemaker.
A pacemaker is designed to mimic the heart’s natural pacemaker, the sinus node. The pacemaker has two main purposes – pacing and sensing.
- Pacing: A pacemaker will send an electrical impulse to the heart through a pacing lead when the heart’s own rhythm is too slow or interrupted. This electrical impulse starts a heartbeat.
- Sensing: A pacemaker will also “sense” (monitor) the heart’s natural electrical activity. When the pacemaker senses a natural heartbeat, it will not deliver a pacing pulse.
Depending on your heart condition, your doctor will prescribe either a single or dual chamber pacemaker. This refers to the number of heart chambers that need to be paced, or sensed.
For single chamber pacing, either the right atrium (upper chamber) or the right ventricle (lower chamber) is paced. Only one pacing lead is used.
For dual chamber pacing, both the right atrium and right ventricle are paced. This requires two pacing leads. One lead is placed in the right atrium, and the other lead is placed in the right ventricle. Revo MRI is a dual chamber pacemaker.