Cardiac Resynchronisation Therapy

If you have heart failure, you may be a candidate for cardiac resynchronization therapy (CRT).

What is CRT and how can it help your heart?

CRT, or biventricular pacing, improves the heart’s efficiency and increases blood flow. Clinical studies have shown that it decreases hospitalization, morbidity and improves quality of life in suitable patients. Unfortunately, up to a third of patients may fail to see an improvement after CRT implantation.

How is the device implanted?

The procedure involves implanting a pacemaker(CRT- Pacemaker) or defibrillator (CRT-Defibrillator), through an incision that is made by the Cardiologist,usually just below the collarbone. Three (sometimes two if you have atrial fibrillation) wires (leads) are then inserted into the heart and connected to the device. The procedure can be performed with general or local anaesthesia. It is important for you to discuss your preferences with your doctor.

The device has on-board diagnostic capabilities that monitor the heart rate to detect heart rate irregularities and emit tiny pulses of electricity to correct them. If your device is a CRT-Defibrillator, this may involve the detection and treatment of dangerously fast heart rhythm abnormities that may arise from the lower chambers of the heart (ventricular tachycardia/ventricular fibrillation). Further still, by improving the coordination of the contraction between the heart chambers, it is in effect “Resynchronizing” the heart hence the name.

Who is a Candidate for CRT?

There are specific groups of patients who have been shown to benefit from CRT. In general, CRT is for heart failure patients with moderate to severe symptoms in whom medical therapies have been unsuccessful.

The cardiologist will assess your symptoms, heart muscle function with a cardiac ultrasound (echocardiogram) and your ECG in deciding whether you’re likely to benefit from CRT.

What are the risks of CRT implantation?

In general, there is a 1-2% chance of complications which may include:

  1. Collapsed lung (pneumothorax)
  2. Excessive bleeding/bruising
  3. Infection
  4. Damage to the heart muscle and/or blood vessel walls
  5. Blood clots in veins that are used in passing the leads to the heart
  6. A remote possibility of heart attack, stroke or death following the procedure
  7. A small risk of reacting to the antibiotics or dye (contrast) which is occasionally injected to facilitate passage of the wires into the blood vessels
  8. Complications related to the anaesthetic or sedation given during the procedure
  9. CRT-D devices may deliver shocks that are triggered by rhythms other than ventricular tachycardia (VT) or ventricular fibrillation (VF). In one study 13% of patients had inappropriate shocks during 2 years of follow-up. Changes in your medications may be required to prevent this. In addition, recent innovations in ICD technology and how they are programmed has been shown to reduce the incidence of inappropriate shocks.

The actual risk of harm resulting from CRT device implantation may be lower or higher, depending on your medical circumstances. The cardiologist will discuss this with you before the procedure.