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Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) uses pulses of electricity to help the ventricles, or the 2 lower chambers of the heart, beat as they should. CRT is used to help moderate to severe heart failure. It is also used to help coordinate the beating of the ventricles when they aren’t coordinated.

Heart failure is a condition in which the heart can’t pump enough blood to meet the body’s needs. Heart failure can cause fatigue and shortness of breath. Until recently, people with heart failure had few options other than lifestyle changes, medications, and sometimes heart surgery. Often, these treatments could not completely control symptoms. Today, however, many people with heart failure are candidates for CRT.

By helping the ventricles beat as they should, CRT can improve how the heart pumps blood. This can ease the symptoms of heart failure, improve quality of life, and make it easier to exercise.

How does CRT work?

CRT involves implanting a pacemaker attached to wires that are threaded into specific areas of the heart. The wires use pulses of electricity to help the left and right ventricles beat as they should. Unlike a typical pacemaker or implantable defibrillator, a CRT device sends pulses to both of the heart’s ventricles at the same time. This is sometimes called “biventricular pacing.”

Up to 40% of CRT users also have potentially life-threatening irregular heartbeats. CRT devices can also be combined with defibrillators that deliver electrical shocks to the heart to correct irregular heartbeats. This type of combination therapy is called CRT-D. 

Are you a candidate for CRT?

You may be an ideal candidate for CRT if your heart failure is serious enough to affect the electrical activity of your heart and cause heart failure symptoms even if you take heart medications. Talk with your doctor to find out whether you are a candidate for CRT.

Recent studies suggest that not all people with heart failure can be helped by CRT. People who have advanced heart failure, for example, aren’t as likely to respond well to CRT. In general, studies suggest that CRT improves the survival, heart function, quality of life, and exercise capacity for people with less severe heart failure. That means heart failure rated as mild to moderate.

What happens during the CRT procedure?

Putting a CRT device in place requires minor surgery. Your doctor will give you medications to help you relax or fall asleep. The doctor will also numb the area where the device will be placed. Your doctor will then thread the wires of the device through blood vessels into your heart and place them in their desired sites. Your doctor will then insert the small metal device under the skin of your chest and connect the wires to it. The device will deliver the electrical impulses. These are usually painless and can’t even be felt.

You will likely stay in the hospital overnight to make sure the device is working properly. Most people return to their normal routine a few days to weeks after the surgery. Your doctor will give you specific instructions on what you can do after the device is in place.

Do I need to take any particular precautions?

If you have a CRT device, you may need to avoid close and lengthy contact with devices that have magnetic fields. These include cellular phones, mp3 players, electrical generators, and appliances like microwaves. That’s because these machines may interfere with the device’s function. Most people with implantable cardiac devices can still enjoy physical activity, including sports and exercise.

What is the outlook for people who have this therapy?

The outlook for most people with CRT is positive. People who received CRT are less likely to die from heart failure than people who have standard implantable heart defibrillators. People with CRT devices also are less likely to have depression, a common condition among people with heart failure.

To determine whether cardiac resynchronization therapy might be helpful for your heart condition, talk with your health care provider.