Cardiac Resynchronisation Therapy

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What is it?

Cardiac Resynchronization Therapy (CRT) may be part of a permanent pacemaker or cardio-defibrillator system that can help to improve heart pump function in people with an enlarged, weakened heart and symptoms of heart failure.

Some patients with heart failure develop problems with the way the natural electrical impulses spread through their heart, and this may cause their heart to pump in an "uncoordinated" manner. CRT uses electrical impulses delivered via pacemaker electrode wires to both the right and left sides of the heart (also called "biventricular pacing") to "resynchronize" the heart function. A CRT system consists of two parts: a generator (battery) and 2- 3 electrode wires inside the heart.

Who will benefit?

Only certain patients with heart failure and evidence for electrical delay in the heart (assessed from the heart tracing or electrocardiogram) appear to benefit from CRT. The response to the treatment can vary, from dramatic improvements in heart function and symptoms back to near-normal in some people, to no improvement in others. It is not possible to predict how much each person will benefit before the procedure is performed, with an overall chance of response of 70%.

What does the procedure involve?

CRT is often performed as part of an implant of a pacemaker or cardio-defibrillator (ICD) and will occur under heavy sedation. After the area has been numbed with local anaesthetic, the Cardiologist will make a 5 to 7cm incision below the collar bone and a small pocket will be made under the skin to hold the generator. The wires are then fixed into place inside the heart. The additional wire to the left side of the heart required for CRT is inserted through a special passage from within the heart. The incision will be closed with sutures and a dressing applied to the area. You will then be returned to the hospital ward for monitoring overnight. The pacemaker technician will check your CRT pacemaker / ICD and your Cardiologist will review you before discharge, usually the next day.


Do not eat or drink anything for 6 hours before your procedure. You should enquire with your Cardiologist whether you should withhold your medicines (especially blood-thinning medications) before this procedure.

Following the procedure

Visit your local doctor 7 to 10 days after implantation to remove your dressing.

Call Heart Care Victoria or your treating Cardiologist promptly if you have:

  • Redness, swelling or pain around the incision site
  • Fever
  • Ooze or bleeding from the incision site

Your Cardiologist will arrange regular reviews to check on the battery and settings of your CRT pacemaker/ICD and to adjust your medications as required.


It takes a few weeks for the CRT wires to firmly attach inside the heart. Therefore, you need to limit arm movement on the side of your incision.
You should read the consent form and understand the risks involved with this procedure. Please clarify any concerns or queries about this procedure with your Cardiologist before signing this form.

For more information contact us or find your nearest test location.

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