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Home > Our Services > Conditions and Treatments > Cardiac Resynchronization Therapy (CRT)

Cardiac Resynchronization Therapy (CRT)



What is it?


The effective management of coronary artery disease over the past two decades has led to improved patient survival. This has in turn resulted in a worldwide increase in the prevalence of congestive heart failure in survivors.


Evidence accrued from multiple trials have demonstrated significant mortality benefit from implantable cardioverter defibrillators (ICD) and biventricular pacemakers (CRT) in patients with impaired cardiac function; and this has led to an increase in the number of such specialized procedures being performed.


Patients with enlarged hearts and poor heart function often have abnormal coordination of contraction of the heart walls (dys-synchrony). This results in ineffective pumping of blood around the body because of "wasted work". Additionally, this may result in an increased leakage of blood backwards across the heart valve instead of pushing blood forwards (mitral regurgitation).


Using a special pacemaker, wires (leads) can be positioned in the top (atrium) and bottom (ventricles) chambers of the heart in order to re-coordinate (resynchronize) the contraction of the heart chambers. This is called "Cardiac Resynchronization Therapy" (CRT) and has been shown to result in improvement of symptoms, effort tolerance, heart function and survival in most patients.  However, not every single patient with heart failure will be suitable for such treatment, and assessment by a cardiologist is necessary before such a decision can be made.


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What to expect?


Done under sedation and local anaesthetic, the procedure is not dissimilar from a standard pacemaker implant, where a small incision is made in the skin under the collarbone (usually on the left) to house the pacemaker.  Usually, 3 wires (leads) are introduced into the heart through the upper arm veins; using a needle to enter into the veins.  Following positioning of the leads and electrical testing, the leads are connected to the pacemaker and the incision is closed. At the end of the procedure, all that is visible is the closed incision line.


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What to prepare?


  • You may be advised to stop taking certain medications before your CRT.
  • Should you have any allergy, especially allergies to X-ray contrast, any heart rhythm medications and pain-relieving medication, please inform your doctors.


After being discharge


Following the procedure, assessment of remaining battery life and adjustment of the pacemaker are done wirelessly through a special programmer and patients are required to return for regular follow-up.  When the pacemaker battery is depleted in a few years' time, the pacemaker will need to be replaced.


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What are the potential risks or complications?


The risk associated with the procedure is very low, and includes bleeding (from insertion of leads into the veins), temporary injury to the lung (pneumothorax) from the needle used to insert the leads, and infection of the pacemaker and lead systems. Antibiotics are routinely given to reduce the risk of infection.


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Cardiac Resynchronization Therapy