Cardiac Resynchronisation

Cardiac resynchronisation therapy (CRT) is a new form of treatment for severe heart failure. CRT has been shown to reduce the symptoms of heart failure and improve outlook in selected recipients.

CRT is performed using a special form of pacemaker known as a bi-ventricular pacemaker. This device is implanted during a small surgical procedure under the skin beneath the collarbone. Electrical cables run from the device to the heart to stimulate it to beat more strongly and in a more coordinated manner.

Patients in whom a CRT device is indicted are often also prone to abnormally fast heart rhythms that can be dangerous and gives rise to sudden death. Therefore, most patients will receive a CRT device that incorporates defibrillator functions (known as CRT-D). Sometimes your doctor may consider this feature not appropriate for you and will discuss this with you. In this case you will receive only a CRT pacemaker (known as CRT-P).

Cardiac Resynchronisation


CRT insertion is a common procedure. This is performed under local anaesthetic with sedative medication to make you feel comfortable. The procedure takes approximately 1-2 hours and is performed in the cardiac catheter laboratory. This is a special room that has a patient table, X-Ray tube, ECG monitors and other equipment. The staff in the lab will all be dressed in hospital theatre clothes and during the procedure will be wearing hats and masks. Many ECG monitoring electrodes will be attached to your chest area. A nurse or doctor will insert an intravenous line usually into the back of your hand. This is needed as a reliable way to give you medications during the study without further injections.

You will also have a blood-pressure cuff attached to your arm that will automatically inflate at various times throughout the procedure. There will also be considerable attention at cleaning the skin under the collarbone where the device will be inserted. You will also receive antibiotics prior to the procedure. You should ensure that you inform the Doctor if you have any allergies.

The CRT device is inserted just under the collarbone. The area is prepared with a special sterile solution that may feel cold. A large sterile sheet that will partly cover your face will cover you. You will be able to look out from under the sheet to the side and a nurse will be present at all times. You will be given oxygen to breathe by a small tube that is positioned under your nostrils.

At the start of the procedure, the doctor will inject local anaesthetic into the area under the collarbone where the CRT device is to be inserted. This will sting momentarily but the area will then be numb. During the procedure you may feel some firm pushing in the shoulder area but this should not be painful. If you experience pain or discomfort you should tell the nurse or doctor. If you are receiving a CRT-D device, at the end of the procedure a fast heart rhythm will be induced and the effectiveness of the defibrillator will be tested. For this testing you will receive stronger sedation or occasionally a general anaesthetic. It is unlikely that you will remember much of the procedure.

After the procedure you will have some bruising and discomfort in the area of the pacemaker that may persist for several weeks. You should avoid strenuous activities with your arm for a period of 4 weeks. If the CRT device is implanted without previous rhythm disturbance (primary prevention) you are legally required to refrain from driving for 2 weeks after the procedure. If the CRT device is implanted after previous rhythm disturbance (secondary prevention) you are legally required to refrain from driving for 6 months and then after clearance by your Doctor.

You will be allowed to go home 1 or 2 days after the procedure.


Procedural risks of CRT implantation are summarised below:

  • All patients will be left with a scar and a CRT device (which can usually be felt) under the skin.
  • Most patients will have some initial bruising. If you are taking aspirin, clopidogrel, warfarin or other “blood thinners” the bruising may be significant.
  • 1 in 40 – The leads can move after the procedure – this may require a repeat procedure to fix the problem.
  • 1 in 100 – An infection may arise at the device site. This is a difficult problem to treat and may require the device to be removed.
  • 1 in 100 – A lung may collapse. This may require the insertion of a tube to reinflate the lung.
  • 1 in 200 – A blood clot may form in the subclavian vein. This is the vein that the leads go through to get to the heart.
  • 1 in 1000 – The leads may puncture the heart muscle, giving rise to cardiac tamponade; which may be fatal.
  • 1 in 1000 – A blood clot can form in the legs and go to the lungs. This may be fatal.
  • Rare – It is possible although rare to have a life threatening allergic reaction to a medication, a stroke, heart attack or die as a result of a CRT device insertion.

Obviously every effort is made to minimise the risks of the procedure and you should be aware that emergency equipment is available to deal with any complications that occur.

It is important to understand that these are average risks. Your individual risk may be higher or lower depending on a number of factors such as your age and general health. Your cardiologist knows these risks and has considered them before recommending that you undergo a CRT implantation.