Cardiac resynchronization therapy is a procedure to implant a device in your chest to make your heart's chambers contract in a more organized and efficient way.

Cardiac resynchronization therapy uses a device called a biventricular pacemaker that delivers electrical signals to both of the lower chambers of your heart (ventricles). The signals tell your ventricles to contract at the same time, maximizing the amount of blood that's pumped out of your heart.

Sometimes the device also contains an implantable cardioverter-defibrillator (ICD), which can deliver stronger electrical shocks if your heart rhythm becomes dangerously erratic.

Why it's done

Cardiac resynchronization therapy is a treatment for heart failure in people whose ventricles don't contract at the same time.

If you have heart failure, your heart muscle is weakened and may not be able to pump out enough blood to support your body. This can be worsened if your heart's chambers aren't in sync with each other.

Cardiac resynchronization therapy delivers electrical signals that cause your heart to beat in a way that maximizes the amount of blood that's pumped out of your heart. This treatment may reduce your symptoms of heart failure and reduce your risk of heart failure complications, including death.

What you can expect

Cardiac resynchronization therapy requires a minor surgical procedure to implant a device in your chest.

You'll likely be awake during the procedure, though the area where the pacemaker is implanted is numbed and you'll receive medication to help you relax (conscious sedation). The procedure typically takes a few hours.

During surgery, insulated wires (leads, or electrodes) are inserted into a major vein under or near your collarbone and guided to your heart with the help of X-ray images. One end of each wire is secured to the appropriate position in your heart, while the other end is attached to a pulse generator, which is usually implanted under the skin beneath your collarbone.

Types of cardiac resynchronization therapy devices include:

  • Cardiac resynchronization therapy with a pacemaker (CRT-P). The device used for cardiac resynchronization therapy has three leads that connect the pacemaker to the right upper chamber of your heart (right atria) and both lower chambers (ventricles).
  • Cardiac resynchronization therapy with a pacemaker and an ICD (CRT-D). People with heart failure who also have a risk of sudden cardiac death may benefit from an ICD that can detect dangerous heart rhythms and deliver a stronger correcting shock of energy than a pacemaker can deliver. In these cases, a cardiac resynchronization therapy device that works as both a pacemaker and an ICD may be recommended.

You'll usually stay overnight in the hospital after cardiac resynchronization therapy. Your doctor will test your device to make sure it's programmed correctly before you leave the hospital. Most people can return to their usual activities after a few days.

Last Updated: 12-28-2017
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