Heart Failure Devices - Cardiac Resynchronization Therapy (CRT)

Photo of doctor talking to patient

How to Prepare
What to Expect
What Happens Next

The heart failure device may be called a bi-ventricular pacemaker or cardiac resynchronization therapy (CRT) system. This type of device is implanted in your body.

A CRT system consists of the pulse generator and three thin, insulated wires called leads.


  • The pulse generator is a small computer like device. It uses lead wires to deliver tiny amounts of electrical energy to the ventricles.
  • The energy impulses help the ventricles contract at the same time, or "resynchronize."
  • When the ventricles pump together, the heart can work more efficiently. This helps the body get the blood it needs to live and work.

A CRT device has the ability to improve your heart health. A CRT device does not cure heart failure. But many people who receive a CRT device notice that they feel better. They experience relief from their symptoms, such as shortness of breath. They also have more energy to participate in everyday activities.

Cardiac resynchronization therapy (CRT) is one treatment option for some heart failure patients. A CRT device helps a heart failure heart (“cardiac”) beat more like a normal heart (“resynchronization”) using electrical pulses timed together (“therapy”).

Learn more about Heart Failure.


How to Prepare

Your healthcare provider will give you specific instructions about preparing for your implant procedure. Follow the instructions carefully.

Your healthcare provider determines whether you should continue or stop certain medications, if you should avoid eating or drinking in the hours before surgery and what to expect when you check into the hospital.

It is important for you to tell your doctor if you cannot take aspirin or have a history of bleeding problems. Your doctor also needs to know if you are taking any other medications, have drug allergies, or are allergic to any metals or plastics.


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What to Expect

The procedure to implant a CRT system in your body typically takes two hours or more. During the surgery, you will be attached to monitors for your heart rate and blood pressure.

An intravenous (IV) line will be started in your arm and you will be given medicine to help you relax and get sleepy. This is called conscious sedation, which means you remain aware of your surroundings and are able to talk to the staff, but you should not feel any pain.


Implanting a Bi-ventricular CRT System - Watch the Video [01:13]



Placing the pulse generator and leads
Your doctor will determine the best way to implant your pulse generator. Your age and the size of your heart will be considered. Your doctor will also consider whether you have ever had chest surgery. Your activities and lifestyle may suggest where the device is implanted. Illustration of the Biventricular CRT system

Your device will likely be implanted just under the skin beneath the shoulder. Coated wires called leads carry the electrical signals between the device and the heart.

For most patients, the leads are placed inside the heart. The doctor opens a vein, usually through a small cut near your collarbone. The doctor will then pass these leads through the vein into your heart (one in the right atrium and the other in the right ventricle), where the tips of the leads will rest directly against your heart’s inner wall. A third lead will also be inserted into a vein near your collarbone, and placed within a coronary vein, which lies on the outside surface of your heart’s left ventricle.

In some cases, a patient may need to have the third lead placed on the heart’s surface. This lead is placed through an incision on the side of the chest instead of through a vein. The lead is attached to the cardiac outer surface, the myocardium. Your doctor will discuss whether this type of chest surgery is an alternative for you.

After the leads are positioned, they will be tested to make sure they clearly sense your heart signal and can adequately pace your heart. After this testing, the device will be connected to the leads and placed in position (usually below the collarbone, just beneath the skin).

Testing the System
As mentioned before, there are two types of cardiac resynchronization systems (CRT) to treat heart failure. Testing will be different depending on which device you have to treat your heart failure.

  • The CRT-P system paces both ventricles (the lower chambers of the heart) to make the heart pump more efficiently. Testing will ensure that the CRT system senses and paces effectively.
  • The CRT-D system provides pacing therapy to make the heart pump efficiently and can defibrillate the heart when an arrhythmia occurs. Testing will ensure that the CRT system senses and paces effectively and can defibrillate ventricular arrhythmias effectively.

To test the CRT-D system, your doctor will start an arrhythmia in your heart. The device will recognize the rhythm and give the programmed treatment. These steps are taken to insure that the CRT-D system can adequately sense the life-threatening rhythms and deliver the appropriate energy to treat them.

When the testing is finished, your doctor will close the pocket that holds the pulse generator. You may experience some discomfort from the incision as you recover from the surgery.


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What Happens Next

The procedure to implant the CRT system typically takes two hours or more. In most hospitals the doctor talks to the family right after the implant—usually to answer questions and to report how the procedure went. The doctor may also see you in the recovery room, although you may be too groggy to talk very long. You might even forget talking to the doctor.

It's a good idea for a couple of family members or friends to be at the hospital. They can talk to the healthcare provider after the procedure. They can then fill you in on the details when you are more alert and help you gather questions for the next time the healthcare provider sees you.

Testing your CRT-D system
If you have a CRT-D system, your doctor may test the system again before you leave the hospital. Your experience of CRT-D therapy will be as unique as you are. People with abnormal heart rhythms may experience unusual sensations during their arrhythmias, but not everyone feels their arrhythmias.

Your CRT-D system is designed to deliver treatment based on what it senses even if you don't feel any symptoms. However, you may feel sensations during therapy delivery. These feelings have been described in a variety of ways.

  • Antitachycardia pacing – You may not feel pacing therapy when it is delivered to your heart. You may have a feeling of fluttering in your chest. Most patients who receive ATP therapy say it is painless.
  • Cardioversion – These low-energy shocks are stronger than pacing pulses. Many patients say cardioversion is mildly uncomfortable. It feels like a thump on the chest.
  • Defibrillation – Many patients faint or become unconscious shortly after a very fast VT or VF rhythm starts. As a result, they do not feel these high-energy shocks. Of those patients who are conscious, some describe the shock like a "kick in the chest." Usually, the shock comes suddenly. The sensation lasts for only a second. While many find the shock reassuring, other patients may feel anxious for a short time after shock therapy is delivered.
  • Bradycardia pacing – These pacing pulses are very low energy and typically, patients do not feel them.

If any of the following are experienced, it is very important to call the healthcare provider.

  • Bleeding at the insertion site
  • Increased pain
  • Any complaint of chest pain
  • Shortness of breath
  • Feeling cold, have swelling, or numbness on the arm or leg of the insertion site
  • The bruising or lump at the insertion site gets larger
  • Fever over 100° F
  • Return of arrhythmia symptoms

Be sure to talk with your healthcare provider so that you thoroughly understand all of the risks and benefits associated with the implantation of this system. As you recover from your implant surgery, you will find that your device may allow you to return to your normal activities.


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