Pacemakers and defibrillators


A pacemaker is a device that prevents the heart from going too slowly. It may be needed if the hearts own pacemaker (the sinus node) is not working, in cases of heart block (where the electrical messages from the sinus node fail to travel through the hearts own wiring system) or in some cases of atrial fibrillation where the heart goes too slowly.

How does a pacemaker work?

The pacemaker consists of a pacemaker pulse generator or 'box' and one, two or sometimes three leads (see biventricular pacemakers below). The leads connect the heart muscle to the pulse generator. If the pacemaker detects that the heart arte is satisfactory then it will simply watch the heart rate. If it detects that the heart rate is too slow it will deliver an electrical impulse down the leads into the heart stimulating the heart muscle to contract. It will repeat the impulse and continue to do this as long as the heart's own rate is too slow.

How is a pacemaker put in?

The pacemaker is fitted under local anaesthetic, often as a day case. It is put in through under an incision beneath the collar bone (on the left in right handed people and vice versa). Through this incision a vein is found and through this vein the leads or leads of the pacemaker are guided around to the heart using an x-ray machine above. You do not feel the leads inside although sometime they can trigger some extra beats felt as palpitations. Once the leads are in the correct place they are tested to check they connect well with the heart and then secured in place . The leads are then attached to the pacemaker generator itself, which is thinner and smaller than a matchbox. This pacemaker  generator box is then tucked under the skin and the wound closed with a stitch.

How long does a pacemaker last?

Pacemakers are powered by a long lasting battery. The actual life of the battery depends on how much the pacemaker is used, but on average it is 5 to 10 years. Usually this can then be replaced by a simple incision over the pacemaker under local anaesthetic without having to renew the leads if they are still working well.

Are there any risks?

The risks to pacemaker insertion are small. Your doctor will have considered these and they will have been weighed up against the benefits and will be discussed with you.

Bruising is common but very rarely a problem.

Infection is uncommon - the procedure is always carried out as a sterile operation - but occasionally infection infections occur in the days after implantation. These are important as they can spread and the pacemaker may need removal. If the wound becomes red after pacemaker implant you should let the hospital know.

Lead displacement - occasionally the leads can move and stop working or not work as well. This will usually only happen in the days and few weeks after the impknattion, and after tis they become firmly attached to the heart. Movement  will be detected by the pacemaker check and somtiems the elads have to be repositioned.

Pneumothorax (a leak of air from a lung and collapse of a lung)) or collection of blood around the heart (tamponade) can sometimes happen during the case. These are rare but important and need to be corrected by a drain or tube either into the lungs or around the heart.

How is the pacemaker checked?

The pacemaker is checked shortly after implantation and at regular intervals by placing a device over the skin which can communicate electronically with the pacemaker. This will check that the leads and the pacemaker are working well and how much battery life there is.

Life after the pacemaker

For the first four weeks after the pacemaker you will be advised not to raise your arm on the side of the pacemaker above your head to avoid the leads being pulled while they are healing in. It is still important to keep the shoulder moving during his time though and more instructions will be given to you before you leave hospital. After this you can go back to normal. The pacemakers are lightweight small devices which allow a normal activities. The only real problems are activities that might cuase direct damage to the pacemaker such as  contact sports.

Will the electronic devices interfere with the pacemaker?

You can still use mobile 'phones, although it is best to keep the 'phone 6 inches away and so use the ear on the opposite side. MP3 players, ipods etc. can be used but do not keep them in a pocket over the pacemaker. There is no evidence that wireless networks interfere with pacemakers.

Airport security systems rarely cause problems with pacemakers, but the pacemaker will be detected and you should carry the pacemaker identity card with you and tell the airport security staff. Normally they will have a hand search or a hand held metal detector (but not over the pacemaker). If you are asked to walk through the security system either at an airport or when going through security systems outside shops walk through steadily without lingering.

Can I drive?

You will need to contact the DVLA and let them know about the pacemaker. If you have an ordinary license then you will be able to drive one week after pacemaker implantation providing there are no other medical disqualifications such as recent heart attack. For a Group II license or PCV license you will not be able to drive for six weeks and will need authorisation form the authorities before you restart using your license. There is guidance on the DVLA website and it is always best to check.


Biventricular Pacemakers

In some cases of heart failure the right and left ventricles of the heart work at difrent times and work against each other (dysynchrony). In these cases a pacemaker with three leads (two to the bottom of the heart and one to the top) can be used and the ventricle 'resynchonised'. This is a more difficult and time consuming procedure than a simple pacemaker. Not all hearts will respond and patients are carefully assessed before such a device is implanted to make sure that they will benefit. They are carefuilly follwoed up and programmed usually at the present time in a specialist centre.




Implantable cardiioverter defibrilators or ICDs are devices implnated to prevent the heart going too quickly. They are implanted in a similar fashion to pacemakers and like pacemakers they monitor the electrical activity of the heart. If the heart races away in a dangerous rhythm such as ventricular tachycardia or ventricular fibrillation the device will recognose this and deliver an internal shock to promptly correct the rhythm.

ICDs are used in people in whom there is already evidence of a ventricular arrhythmias which could recur (secondary prevention) or in some cases in those with high risk of ventricular arrhythmia (siuch as in some poelpe with hypertrophic cardiomyopathy or after heart attack with significantly damaged heart muscle (primary prevention).

ICDs are larger slightly larger ordinary pacemakers and in thin people may be implanted deeeper behind the muscle in the chest wall. They are carefuilly follwoed up and programmed usually at the present time in a specialist centre.

Please note:

Every effort has been made to ensure that the information on this website is up-to-date and accurate. However, it is intended to serve as a guide only. Symptoms may vary and if you have any medical concerns you should always consult a healthcare professional.

Every effort has been made to ensure that the information on this website is up-to-date and accurate. However, it is intended to serve as a guide only. Symptoms may vary and if you have any medical concerns you should always consult a healthcare professional.