Cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is a treatment for some people who have heart failure. It helps the heart chambers squeeze in a better and more organized way. CRT helps the heart better pump blood to the body.

The therapy uses a device called a biventricular pacemaker, also called a cardiac resynchronization device. The device sends electrical signals to the lower chambers of the heart, called the ventricles. The signals tell the ventricles to squeeze at the same time.

Some CRT devices also have a device called an implantable cardioverter-defibrillator (ICD). An ICD fixes a dangerous heart rhythm.

Why it's done

Cardiac resynchronization therapy (CRT) treats some people with moderate to severe heart failure. Healthcare teams usually try other treatments, including medicines, before they recommend CRT.

Your healthcare team may suggest CRT if:

  • You have heart failure and an irregular heart signaling condition such as left bundle branch block.
  • You need a pacemaker or defibrillator due to a heart condition.

Cardiac resynchronization therapy may help lessen symptoms of heart failure such as shortness of breath. When used with other treatments, CRT may:

  • Improve your quality of life.
  • Lower your risk of a hospital stay due to heart failure.
  • Help prevent heart failure complications.

CRT is not meant for people who have only mild heart failure symptoms.

Risks

Risks of cardiac resynchronization therapy (CRT) depend on your overall health and the type of CRT device you have.

Risks related to the device and surgery to place the device may include:

  • Infection.
  • Bleeding.
  • A collapsed lung.
  • A hole in a heart chamber, which can cause fluid and blood to collect in the sac surrounding the heart.
  • Failure of the device.
  • Movement of device parts, which may require another procedure to fix.

What you can expect

Cardiac resynchronization therapy (CRT) requires a minor surgery to place a device in the chest. CRT devices are:

  • Cardiac resynchronization therapy pacemaker (CRT-P). This device is for people who have certain stages of heart failure and irregular heart signaling. It sends signals that make the lower heart chambers, called the ventricles, beat at the same time. It helps the heart properly fill with blood.
  • Cardiac resynchronization therapy defibrillator (CRT-D). This combination device uses a pacemaker and an implantable cardioverter-defibrillator (ICD). It may help people with heart failure who are at risk of sudden cardiac death. It can find harmful heart rhythms and fix them. It can pace the heartbeat or give a shock to stop a dangerous heart rhythm.

Before

A member of your healthcare team puts a needle with a flexible tube attached to it, called an IV line, into a vein in your forearm or hand. Medicine called a sedative goes through the IV. It helps you relax.

Usually, you get medicine to numb the skin where the CRT device will go. This is called local anesthesia. During the surgery to place the device, you may be fully awake or lightly sedated.

During

The surgery to place the CRT device usually takes a few hours.

How the surgery is done may depend on the type of CRT device you get.

For example, to place a pacemaker, a heart doctor makes a small cut, called an incision, just below your collarbone. Your doctor then inserts one or more wires, called leads, into a major vein in your chest. The doctor moves the leads to the heart using X-ray images as a guide. One end of each wire connects to the proper area in the heart. The other end attaches to the part of the CRT device that sends electrical pulses.

After

You usually stay in the hospital overnight after getting a cardiac resynchronization therapy (CRT) device. Make plans to have someone drive you home from the hospital.

Most people can go back to their usual activities a few days after they get a CRT device. Your care team gives you specific instructions to follow. You may need to limit upper body and arm activities. Your healthcare team also may tell you not to do hard exercise or lift heavy items for about a month.

June 04, 2025
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