What is Cardiac Resynchronization Therapy (CRT)?

Cardiac resynchronization therapy is a procedure for implanting a device in the chest to make the heart chamber squeeze in a more organised and efficient way.

Cardiac resynchronization therapy uses a device named a biventricular pacemaker (also called a cardiac resynchronization device) which sends electrical signals to both lower chambers of the heart (ventricles). The signals trigger the ventricles to contract in a more coordinated way that improves the pumping of blood. Sometimes the device contains an implantable cardioverter-defibrillator (ICD) which delivers an electrical shock to reset the heartbeat if the heart rhythm becomes dangerously erratic.

cardiac resynchronization therapy


Why is Cardiac resynchronization therapy done?

The doctor will suggest Cardiac resynchronization therapy for the following reasons:

  • If you have moderate to severe heart failure symptoms.
  • If the pumping chambers of the heart are not working together.
  • The test will show how weak is your heart.
  • If medications and lifestyle changes are not working well enough for controlling heart failure.

Risks of Cardiac resynchronization therapy

Multiple medical procedures come with few risks. Some specific risks of Cardiac resynchronization therapy depend on the type of implant and on the overall health. This includes:

  • Reaction to the anaesthesia
  • Swelling or bruising in the upper chest area, where CRT device is placed
  • Bleeding
  • Infection
  • Heart rhythm problems
  • Movement of the device or device wires
  • Injury to a blood vessel

Cardiac resynchronization therapy (CRT) Procedures

Before the CRT Procedure

The patient should first discuss all the risks and benefits of the procedure with the doctor. The doctor will ask you not to eat or drink anything before the surgery. If you are taking any kind of medicine, talk with your doctor about whether to take them or not.

The doctor may ask you to stop the medicines which thin your blood. Talk with your doctor about:

  • Any prescribed or non-prescribed medicines that you are taking.
  • Any Over-the-counter medicines or supplements you are taking.
  • Any allergies you have.
  • Any symptoms of colds or infections.
  • Any problems related to anesthesia.

During the CRT procedure

  • The procedure can take 3 to 5 hours.
  • The doctor will put an intravenous (IV) line in your hand or arm. Through this line, your healthcare team will give you fluids, antibiotics, and pain medication.
  • The doctor team will control the pulse, blood pressure and level of oxygen.
  • The patient will be given medicines to relax. Later on, the doctor will give anesthesia to numb the area where the device is being placed. Mainly, under the left collar bone.
  • The doctor will put intravenous lines in the large vein which feeds the heart. CRT wires will be inserted into the vein and fed into the heart. X-rays would be taken to make sure if the CRT wires are in the right place.
  • The doctor will test the CRT wires with an electric pulse.
  • If the CRT wires are at the right place and working properly then they will be attached to the CRT pacemaker. The doctor will put the pacemaker through the incision and under the skin.
  • Then the doctor will close the incision with sutures or staples

After the CRT procedure

The patient will be moved to a recovery area. He may be asked to stay at the hospital for a day or two while the doctor will check and adjust the settings on the CRT device.

After leaving the hospital it’s very important to follow the doctor’s instructions for avoiding any serious conditions.

Steps to be followed at home:

  • Follow a normal diet
  • Limit some of the activities like lifting, straining, and stretching at least for 6 weeks.
  • Keep the dressing clean and dry until the doctor tells you to.
  • Check the incision area frequently for any signs and infections.
  • Visit your doctor regularly at least every 6 months

Cardiac resynchronization therapy devices include:

Cardiac resynchronization therapy with a Pacemaker (CRT-P)

The device is mainly used for Cardiac resynchronization therapy and has three leads that connect the pacemaker to the right upper chamber of the heart (right atria) and both lower chambers (ventricles).

Cardiac resynchronization therapy with a Pacemaker and an ICD (CRT-D)

The device is recommended for patients with heart failure who are at high risk of mortality from a heart attack. The device can also detect dangerous heart rhythms and give a higher electrical shock capable of resetting the heartbeat than a pacemaker.



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Frequently Asked Questions

1. Is Cardiac Resynchronization Therapy the same as a pacemaker?

There are two types of Cardiac resynchronization therapy devices. One device is a special kind of pacemaker. This is called a cardiac resynchronization therapy pacemaker (CRT-P) or biventricular pacemaker. Another device is called Cardiac resynchronization therapy with a pacemaker and an ICD but it also includes a built-in implantable cardioverter-defibrillator.

2. How is cardiac resynchronization therapy done?

CRT therapy means you will need to have the pacemaker placed under the skin by minor surgery. Wires from the devices are connected to the ventricles on both sides of the heart. The CRT will send electrical signals to the ventricles for making them pump together.

3. What are the disadvantages of having a Cardiac Resynchronization Therapy?

Infection at the surgical site and/or reaction to the device material, inability to provide therapy when it is needed, or obtaining additional therapy when it is not needed are all risks associated with it.

4. Does CRT improve survival?

In selected patients with heart failure (HF), reduced left ventricular (LV) function, and a broad QRS complex, randomised controlled trials (RCTs) have indicated that cardiac resynchronization therapy (CRT) prolongs survival and lowers morbidity.

5. How long does a CRT procedure take?

The CRT device may be implanted as an outpatient procedure or as part of a hospital stay. Procedures may differ depending on your situation and the practices of the doctor. Discuss what will happen during the procedure with the doctor. The operation will take 3 to 5 hours.

Citations:

https://www.heart.org/en/health-topics/heart-failure/treatment-options-for-heart-failure/cardiac-resynchronization-therapy-crt
https://en.wikipedia.org/wiki/Cardiac_resynchronization_therapy
https://www.nejm.org/doi/full/10.1056/nejmoa032423
https://academic.oup.com/europace/article/11/suppl_5/v58/468520?login=true
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4295737/