Why do I need a pacemaker?

 

Information for people with pacemakers, and for their family an friends

The normal healthy adult human heart has a regular beat, which is usually within a range of 50 and 100 beats a minute.

 

The heart has four `chambers'. The two upper chambers are called the `right atrium' and the 'left atrium' (the atria). The two lower chambers are the `right ventricle` and `left ventricle`. (See the illustration below.)

The heart has its own `natural pacemaker'. A group of cells on the right side of the heart transmit regular electrical impulses across the two atria. Where the atria meet the ventricles (the two larger pumping chambers) there is another group of cells called the atrio-ventricular node (or 'AV node'). As the

electrical impulses pass from the AV node to the ventricles, they stimulate a contraction or heartbeat.

 

 

You may need to have a pacemaker implanted:

a) if you have 'heart block', or

 b) if you have certain types of irregular heart rate or heart rhythm.

If you have heart block

The electrical impulses of the heart are sometimes slowed down or delayed by an interruption in the heart's normal electrical activity. This condition is known as 'heart block'. At its most advanced stage, called 'complete heart block', no electrical impulses cross to the ventricles at all.

The atria and ventricles beat independently of each other. This means that, even if the atria are not beating normally, the ventricles are still able to beat at their own rate of about 40 beats a minute. However, at this slow rate, the reduced blood flow may cause breathlessness, fainting, blackouts or even confusion.

Heart block is usually caused by heart disease or ageing of the heart. Both of these can affect the way the heart's natural pacemaker works and the spread of electrical activity through the heart. Heart block can also occur after a heart operation - either temporarily or permanently.

If the cause of the heart block cannot be put right, your doctor will recommend that you have an artificial cardiac pacemaker, to help maintain your heartbeat.

Some people have slow heart rhythms which can be life­ threatening, and may need an emergency pacemaker implantation.

If you have an irregular heart rate or heart rhythm

Pacemakers are also sometimes recommended for people with intermittently slow and fast heart rates, or irregular heart rhythms, to help maintain a steady, regular heartbeat.

'Catheter ablation therapy' is a relatively new form of treatment used to correct certain abnormal heart rhythms. The procedure involves applying radio-frequency energy to the area of the heart that is responsible for the abnormal electrical signal. In some cases a permanent pacemaker may also need to be implanted to ensure a regular heart rhythm.