Heart failure happens when your heart is no longer able to pump enough blood to meet your body’s needs. Sometimes it is also called congestive heart failure.

For many people with heart failure, cardiac resynchronization therapy (CRT) can be a life saving treatment. It synchronizes the beating of your heart’s two lower chambers (ventricles) so the heart can pump out blood more effectively.

CRT uses an implantable device placed in the chest. The device has wires (called leads) that connect with the heart. These leads carry a small electrical signal to stimulate the ventricles.

Some risks are associated with the CRT procedure. But advances in technology continue to improve CRT and its effectiveness.

Heart failure can result from conditions that weaken the heart muscle. These conditions include:

Heart failure is often classified based on the heart’s ability to pump blood throughout the body, as outlined below:

Heart failure classification

  • Heart failure with reduced ejection fraction (HFrEF): HFrEF is when the heart has become weaker and can’t pump enough blood to meet the body’s demand for robust circulation.
  • Heart failure with preserved ejection fraction (HFpEF): HFpEF means the heart is strong enough to pump effectively, but the left ventricle can no longer relax properly. As a result, it can’t fill with enough blood to consistently meet the body’s needs. This means less blood is pumped out with each contraction.

CRT is appropriate for people with HFrEF who have an arrhythmia that keeps the heart from beating in a regular, predictable rhythm.

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When the ventricles beat at different times, the heart cannot work efficiently.

As a result, fluid can build up in the lungs and the legs. These are the hallmark symptoms of congestive heart failure. If they are not treated, they can cause a dangerous reduction in blood flow to the organs and the rest of the body.

CRT uses a pacemaker to help the heart’s upper chambers (atria) beat in a coordinated rhythm with the lower chambers (ventricles). With CRT, the heart consistently receives electrical impulses that support a more coordinated beating and relaxation of the heart. This helps support better blood flow.

CRT use has grown steadily since it was first approved in 2001. However, a 2016 report suggests that the vast majority of people who undergo CRT are male and white and that significant racial and socioeconomic barriers to this treatment still exist.

CRT is usually an option only after medications or other treatments have not worked to boost the heart’s pumping function.

Your doctor will likely explain the procedure to you and go over the benefits and risks.

Once you and your doctor decide to proceed with CRT, they’ll give you more instructions about what to do before the procedure. This will likely include details on:

  • when to stop eating food or drinking liquids prior to the procedure
  • when to stop taking medications or supplements that can thin your blood
  • when it may be safe to take other prescription medications for your heart or other conditions

Depending on the severity of your condition, your doctor may decide to do the CRT implementation as part of a hospital stay or as an outpatient procedure.

During the procedure

Implantation of the CRT device is usually done with local anesthesia and takes between 3 to 5 hours to complete. It does not require open heart surgery.

You will be given medication to help you relax and feel sleepy. During the procedure, your healthcare team will monitor your heartbeat, blood pressure, and oxygen level.

Here’s how the procedure itself will go:

  1. Once the local anesthesia has taken effect, your doctor will cut a 2-inch incision and make a pocket just under the skin below your collarbone.
  2. Your doctor will then guide two leads (wires) through a large vein heading to your heart and place the leads on either side of your heart.
  3. Your doctor will then send a mild electric signal through the leads to make sure they work.
  4. If the test is successful, the leads will be attached to the CRT pacemaker. (The CRT pacemaker itself is about 2 inches by 2 inches in size.)
  5. Your doctor will place the pacemaker into the pocket through the incision.
  6. Your doctor will then close the incision and apply a dressing to help keep the incision dry and clean.
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  • In the hours immediately after the procedure, you’ll be observed in a recovery area and given pain-relieving medications as the anesthesia wears off.
  • Depending on the severity of your heart failure, you may need to spend 1 or 2 days in the hospital. During that time, healthcare professionals will check the settings on your CRT and monitor your heart health regularly.
  • Before you leave the hospital or out-patient surgery center, you’ll be given instructions on how to care for your incision. You’ll also be given instructions about what to do if you experience any complications once you get home.
  • Once you’re home, you should avoid heavy lifting and doing strenuous activities for several weeks. It’s important to follow your doctor’s instructions carefully and to go to all follow-up appointments.
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A CRT pacemaker battery can last up to 8 years. Your doctor will be able to tell months before the battery is likely to run out so that you can schedule a replacement procedure.

You will also need to carry a CRT identification card to let all other doctors know your status. It’s also helpful if you need to go through a metal detector at the airport or other locations.

What is the outlook?

Many factors contribute to the outlook after someone undergoes CRT. Age and overall health, including comorbidities (other health conditions), are two key considerations.

A 2021 study of people who got their CRT devices between 2011 and 2013 suggests that the average 5-year survival is about 58%.

However, a separate 2018 study using patient data from 2009 to 2017 suggests that relative survival continues to improve year after year, and that survival rates were notably higher in 2015 to 2017 than they were in 2009 to 2011.

A 2019 report suggests that ongoing developments in device leads and cardiac imaging are allowing doctors to be even more precise with this procedure, which may result in even greater heart function improvements.

Like any medical procedure, CRT implantation carries some risks. But complications such as bleeding or infections are unusual. In rare cases, the therapy can trigger an arrhythmia.

Mechanical problems, such as a lead coming loose or the device not sending impulses properly or consistently, can sometimes occur. As a result, you may need a second procedure to replace the device or lead. In general, though, CRT is considered a safe, low risk treatment for appropriate individuals.

The device should also be implanted only if your doctor believes it will provide a significant improvement. Some people with heart failure are too weak or ill to undergo the procedure and benefit from resynchronization therapy.

If you have HFpEF, or there are no arrhythmias detected with your type of heart failure, CRT should not be a consideration.

While CRT can help many people with heart failure resume some of their usual activities and improve their quality of life, it is not a cure. Though you can often manage heart failure, it cannot be cured.

It’s worth noting that CRT is usually just one component of heart failure treatment. If you have heart failure, you may also be prescribed anti-hypertensive medications to lower blood pressure, including beta blockers, which slow the heart rate and ease the burden on the heart muscle.

Other medications you may be prescribed include digoxin (Lanoxin), which strengthens heart contractions. And, if you have high cholesterol, you may need to take a statin to lower your LDL (“bad”) cholesterol levels.

Depending on the cause, heart failure may be treated with other procedures. For instance, if you have valve disease, surgery or catheter-based procedures to replace or repair a valve may improve your symptoms.

CRT can be a helpful option for many people with heart failure. In particular, it’s a suitable treatment for people with HFrEF who have an arrhythmia that keeps their heart from beating in a regular rhythm.

CRT uses a pacemaker to help the heart’s upper chambers beat in a coordinated rhythm with the lower chambers. In turn, this helps blood to flow more efficiently throughout the body.

CRT won’t cure heart failure, but it’s a therapy that’s extending the lives of many people with heart failure and enabling a quality of life that wasn’t possible just a few decades ago.

If you do undergo CRT, lifelong monitoring and regular checkups with your cardiologist will be necessary.