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What is a Pacemaker?

What does it look like?

A pacemaker is a cardiac device that is made up of the following elements:
  • Battery The battery powers the generator
  • Computerized generator The generator sends electrical pulses through the wires
  • Wires with sensors (electrodes) in their tips The electrodes sense the heart’s electrical activity.
  • The battery and generator are housed in a small metal box, while the wires connect the generator to the heart.


Where is it placed?

During pacemaker surgery, the wires of the pacemaker are placed inside the chambers of the heart. There can be between one and three wires, depending on which type of pacemaker is installed. There are three types of pacemaker. These are:
  • Single-chamber pacemaker Wires carry pulses to the right ventricle
  • Dual-chamber pacemaker Wires carry pulses to the right atrium and the right ventricle to coordinate the contractions in these two chambers.
  • Biventricular pacemakers (also known as a cardiac resynchronization therapy device) Wires carry pulses to the atrium and both ventricles to coordinate the electrical signals between the ventricles.

How does it work?

The main function of a pacemaker is to monitor and control the heartbeat. Electrodes in the wires identify the heart’s electrical activity and send data to the computerised generator. If there is an irregular heartbeat, the generator sends electrical pulses through the wires to the heart. Besides regulating and monitoring the heartbeat, pacemakers can perform a number of other functions. These include:

  • Monitoring blood temperature
  • Monitoring breathing
  • Adjusting heart rate according to changes in physical activity
  • Recording the heart’s electrical activity
  • Recording the heart rhythm

Your cardiologist will look at the recordings of your pacemaker in order to make relevant adjustments. The pacemaker can be programmed with the use of an external device.

What happens at a pacemaker/ICD implantation procedure?